Programs & Examples On #Transactionmanager

A transaction manager is the part of an application that is responsible for coordinating transactions across one or more resources.

Failed to load ApplicationContext (with annotation)

Your test requires a ServletContext: add @WebIntegrationTest

@RunWith(SpringJUnit4ClassRunner.class)
@ContextConfiguration(classes = AppConfig.class, loader = AnnotationConfigContextLoader.class)
@WebIntegrationTest
public class UserServiceImplIT

...or look here for other options: https://docs.spring.io/spring-boot/docs/current/reference/html/boot-features-testing.html

UPDATE In Spring Boot 1.4.x and above @WebIntegrationTest is no longer preferred. @SpringBootTest or @WebMvcTest

Disable all Database related auto configuration in Spring Boot

Way out for me was to add

@EnableAutoConfiguration(exclude = {DataSourceAutoConfiguration.class, DataSourceTransactionManagerAutoConfiguration.class, HibernateJpaAutoConfiguration.class})

annotation to class running Spring boot (marked with `@SpringBootApplication).

Finally, it looks like:

@SpringBootApplication
@EnableAutoConfiguration(exclude = {DataSourceAutoConfiguration.class, DataSourceTransactionManagerAutoConfiguration.class, HibernateJpaAutoConfiguration.class})
public class Application{

    public static void main(String[] args) {
        SpringApplication.run(Application.class, args);
    }
 }

Spring boot - configure EntityManager

Hmmm you can find lot of examples for configuring spring framework. Anyways here is a sample

@Configuration
@Import({PersistenceConfig.class})
@ComponentScan(basePackageClasses = { 
    ServiceMarker.class,
    RepositoryMarker.class }
)
public class AppConfig {

}

PersistenceConfig

@Configuration
@PropertySource(value = { "classpath:database/jdbc.properties" })
@EnableTransactionManagement
public class PersistenceConfig {

    private static final String PROPERTY_NAME_HIBERNATE_DIALECT = "hibernate.dialect";
    private static final String PROPERTY_NAME_HIBERNATE_MAX_FETCH_DEPTH = "hibernate.max_fetch_depth";
    private static final String PROPERTY_NAME_HIBERNATE_JDBC_FETCH_SIZE = "hibernate.jdbc.fetch_size";
    private static final String PROPERTY_NAME_HIBERNATE_JDBC_BATCH_SIZE = "hibernate.jdbc.batch_size";
    private static final String PROPERTY_NAME_HIBERNATE_SHOW_SQL = "hibernate.show_sql";
    private static final String[] ENTITYMANAGER_PACKAGES_TO_SCAN = {"a.b.c.entities", "a.b.c.converters"};

    @Autowired
    private Environment env;

     @Bean(destroyMethod = "close")
     public DataSource dataSource() {
         BasicDataSource dataSource = new BasicDataSource();
         dataSource.setDriverClassName(env.getProperty("jdbc.driverClassName"));
         dataSource.setUrl(env.getProperty("jdbc.url"));
         dataSource.setUsername(env.getProperty("jdbc.username"));
         dataSource.setPassword(env.getProperty("jdbc.password"));
         return dataSource;
     }

     @Bean
     public JpaTransactionManager jpaTransactionManager() {
         JpaTransactionManager transactionManager = new JpaTransactionManager();
         transactionManager.setEntityManagerFactory(entityManagerFactoryBean().getObject());
         return transactionManager;
     }

    private HibernateJpaVendorAdapter vendorAdaptor() {
         HibernateJpaVendorAdapter vendorAdapter = new HibernateJpaVendorAdapter();
         vendorAdapter.setShowSql(true);
         return vendorAdapter;
    }

    @Bean
    public LocalContainerEntityManagerFactoryBean entityManagerFactoryBean() {

         LocalContainerEntityManagerFactoryBean entityManagerFactoryBean = new LocalContainerEntityManagerFactoryBean();
         entityManagerFactoryBean.setJpaVendorAdapter(vendorAdaptor());
         entityManagerFactoryBean.setDataSource(dataSource());
         entityManagerFactoryBean.setPersistenceProviderClass(HibernatePersistenceProvider.class);
         entityManagerFactoryBean.setPackagesToScan(ENTITYMANAGER_PACKAGES_TO_SCAN);             
         entityManagerFactoryBean.setJpaProperties(jpaHibernateProperties());

         return entityManagerFactoryBean;
     }

     private Properties jpaHibernateProperties() {

         Properties properties = new Properties();

         properties.put(PROPERTY_NAME_HIBERNATE_MAX_FETCH_DEPTH, env.getProperty(PROPERTY_NAME_HIBERNATE_MAX_FETCH_DEPTH));
         properties.put(PROPERTY_NAME_HIBERNATE_JDBC_FETCH_SIZE, env.getProperty(PROPERTY_NAME_HIBERNATE_JDBC_FETCH_SIZE));
         properties.put(PROPERTY_NAME_HIBERNATE_JDBC_BATCH_SIZE, env.getProperty(PROPERTY_NAME_HIBERNATE_JDBC_BATCH_SIZE));
         properties.put(PROPERTY_NAME_HIBERNATE_SHOW_SQL, env.getProperty(PROPERTY_NAME_HIBERNATE_SHOW_SQL));

         properties.put(AvailableSettings.SCHEMA_GEN_DATABASE_ACTION, "none");
         properties.put(AvailableSettings.USE_CLASS_ENHANCER, "false");      
         return properties;       
     }

}

Main

public static void main(String[] args) { 
    try (GenericApplicationContext springContext = new AnnotationConfigApplicationContext(AppConfig.class)) {
        MyService myService = springContext.getBean(MyServiceImpl.class);
        try {
            myService.handleProcess(fromDate, toDate);
        } catch (Exception e) {
            logger.error("Exception occurs", e);
            myService.handleException(fromDate, toDate, e);
        }
    } catch (Exception e) {
        logger.error("Exception occurs in loading Spring context: ", e);
    }
}

MyService

@Service
public class MyServiceImpl implements MyService {

    @Inject
    private MyDao myDao;

    @Override
    public void handleProcess(String fromDate, String toDate) {
        List<Student> myList = myDao.select(fromDate, toDate);
    }
}

MyDaoImpl

@Repository
@Transactional
public class MyDaoImpl implements MyDao {

    @PersistenceContext
    private EntityManager entityManager;

    public Student select(String fromDate, String toDate){

        TypedQuery<Student> query = entityManager.createNamedQuery("Student.findByKey", Student.class);
        query.setParameter("fromDate", fromDate);
        query.setParameter("toDate", toDate);
        List<Student> list = query.getResultList();
        return CollectionUtils.isEmpty(list) ? null : list;
    }

}

Assuming maven project: Properties file should be in src/main/resources/database folder

jdbc.properties file

jdbc.driverClassName=com.mysql.jdbc.Driver
jdbc.url=your db url
jdbc.username=your Username
jdbc.password=Your password

hibernate.max_fetch_depth = 3
hibernate.jdbc.fetch_size = 50
hibernate.jdbc.batch_size = 10
hibernate.show_sql = true

ServiceMarker and RepositoryMarker are just empty interfaces in your service or repository impl package.

Let's say you have package name a.b.c.service.impl. MyServiceImpl is in this package and so is ServiceMarker.

public interface ServiceMarker {

}

Same for repository marker. Let's say you have a.b.c.repository.impl or a.b.c.dao.impl package name. Then MyDaoImpl is in this this package and also Repositorymarker

public interface RepositoryMarker {

}

a.b.c.entities.Student

//dummy class and dummy query
@Entity
@NamedQueries({
@NamedQuery(name="Student.findByKey", query="select s from Student s where s.fromDate=:fromDate" and s.toDate = :toDate)
})
public class Student implements Serializable {

    private LocalDateTime fromDate;
    private LocalDateTime toDate;

    //getters setters

}

a.b.c.converters

@Converter(autoApply = true)
public class LocalDateTimeConverter implements AttributeConverter<LocalDateTime, Timestamp> {

    @Override
    public Timestamp convertToDatabaseColumn(LocalDateTime dateTime) {

        if (dateTime == null) {
            return null;
        }
        return Timestamp.valueOf(dateTime);
    }

    @Override
    public LocalDateTime convertToEntityAttribute(Timestamp timestamp) {

        if (timestamp == null) {
            return null;
        }    
        return timestamp.toLocalDateTime();
    }
}

pom.xml

<properties>
    <java-version>1.8</java-version>
    <org.springframework-version>4.2.1.RELEASE</org.springframework-version>
    <hibernate-entitymanager.version>5.0.2.Final</hibernate-entitymanager.version>
    <commons-dbcp2.version>2.1.1</commons-dbcp2.version>
    <mysql-connector-java.version>5.1.36</mysql-connector-java.version>
     <junit.version>4.12</junit.version> 
</properties>

<dependencies>
    <dependency>
        <groupId>junit</groupId>
        <artifactId>junit</artifactId>
        <version>${junit.version}</version>
        <scope>test</scope>
    </dependency>

    <!-- Spring -->
    <dependency>
        <groupId>org.springframework</groupId>
        <artifactId>spring-context</artifactId>
        <version>${org.springframework.version}</version>
    </dependency>

    <dependency>
        <groupId>org.springframework</groupId>
        <artifactId>spring-jdbc</artifactId>
        <version>${org.springframework.version}</version>
    </dependency>

    <dependency>
        <groupId>javax.inject</groupId>
        <artifactId>javax.inject</artifactId>
        <version>1</version>
        <scope>compile</scope>
    </dependency>

    <dependency>
        <groupId>org.springframework</groupId>
        <artifactId>spring-tx</artifactId>
        <version>${org.springframework-version}</version>
    </dependency>

    <dependency>
        <groupId>org.springframework</groupId>
        <artifactId>spring-orm</artifactId>
        <version>${org.springframework-version}</version>
    </dependency>

    <dependency>
        <groupId>org.hibernate</groupId>
        <artifactId>hibernate-entitymanager</artifactId>
        <version>${hibernate-entitymanager.version}</version>
    </dependency>

    <dependency>
        <groupId>mysql</groupId>
        <artifactId>mysql-connector-java</artifactId>
        <version>${mysql-connector-java.version}</version>
    </dependency>

    <dependency>
        <groupId>org.apache.commons</groupId>
        <artifactId>commons-dbcp2</artifactId>
        <version>${commons-dbcp2.version}</version>
    </dependency>
</dependencies>

<build>
     <finalName>${project.artifactId}</finalName>
     <plugins>
         <plugin>
            <groupId>org.apache.maven.plugins</groupId>
            <artifactId>maven-compiler-plugin</artifactId>
            <version>3.3</version>
            <configuration>
                <source>${java-version}</source>
                <target>${java-version}</target>
                <compilerArgument>-Xlint:all</compilerArgument>
                <showWarnings>true</showWarnings>
                <showDeprecation>true</showDeprecation>
            </configuration>
        </plugin>
     </plugins>
</build>

Hope it helps. Thanks

Spring - No EntityManager with actual transaction available for current thread - cannot reliably process 'persist' call

Without @Transactional annotation you can achieve the same goal with finding the entity from the DB and then removing that entity you got from the DB.

CrudRepositor -> void delete(T var1);

UnsatisfiedDependencyException: Error creating bean with name 'entityManagerFactory'

Well, you're getting a java.lang.NoClassDefFoundError. In your pom.xml, hibernate-core version is 3.3.2.GA and declared after hibernate-entitymanager, so it prevails. You can remove that dependency, since will be inherited version 3.6.7.Final from hibernate-entitymanager.

You're using spring-boot as parent, so no need to declare version of some dependencies, since they are managed by spring-boot.

Also, hibernate-commons-annotations is inherited from hibernate-entitymanager and hibernate-annotations is an old version of hibernate-commons-annotations, you can remove both.

Finally, your pom.xml can look like this:

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>

    <groupId>org.elsys.internetprogramming.trafficspy.server</groupId>
    <artifactId>TrafficSpyService</artifactId>
    <version>0.1.0</version>

    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>1.2.3.RELEASE</version>
    </parent>

    <dependencies>
        <!-- Spring -->
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-cloud-connectors</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-jdbc</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-data-jpa</artifactId>
        </dependency>

        <dependency>
            <groupId>org.eclipse.persistence</groupId>
            <artifactId>javax.persistence</artifactId>
            <version>2.0.0</version>
        </dependency>

        <!-- Hibernate -->
        <dependency>
            <groupId>org.hibernate</groupId>
            <artifactId>hibernate-entitymanager</artifactId>
        </dependency>
        <dependency>
            <groupId>org.hibernate</groupId>
            <artifactId>hibernate-validator</artifactId>
        </dependency>

        <dependency>
            <groupId>javax.servlet</groupId>
            <artifactId>jstl</artifactId>
        </dependency>
        <dependency>
            <groupId>commons-dbcp</groupId>
            <artifactId>commons-dbcp</artifactId>
        </dependency>
        <dependency>
            <groupId>commons-pool</groupId>
            <artifactId>commons-pool</artifactId>
        </dependency>

        <!-- MySQL -->
        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
        </dependency>
    </dependencies>

    <properties>
        <java.version>1.7</java.version>
    </properties>

    <build>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
                <executions>
                    <execution>
                        <goals>
                            <goal>repackage</goal>
                        </goals>
                    </execution>
                </executions>
            </plugin>
        </plugins>
    </build>

    <repositories>
        <repository>
            <id>spring-releases</id>
            <url>https://repo.spring.io/libs-release</url>
        </repository>

        <repository>
            <id>codehaus</id>
            <url>http://repository.codehaus.org/org/codehaus</url>
        </repository>
    </repositories>
    <pluginRepositories>
        <pluginRepository>
            <id>spring-releases</id>
            <url>https://repo.spring.io/libs-release</url>
        </pluginRepository>
    </pluginRepositories>

</project>

Let me know if you have a problem.

Spring boot - Not a managed type

Faced similar issue. In my case the repository and the type being managed where not in same package.

org.hibernate.HibernateException: Access to DialectResolutionInfo cannot be null when 'hibernate.dialect' not set

First remove all of your configuration Spring Boot will start it for you.

Make sure you have an application.properties in your classpath and add the following properties.

spring.datasource.url=jdbc:postgresql://localhost:5432/teste?charSet=LATIN1
spring.datasource.username=klebermo
spring.datasource.password=123

spring.jpa.database-platform=org.hibernate.dialect.PostgreSQLDialect
spring.jpa.show-sql=false
spring.jpa.hibernate.ddl-auto=create

If you really need access to a SessionFactory and that is basically for the same datasource, then you can do the following (which is also documented here although for XML, not JavaConfig).

@Configuration        
public class HibernateConfig {

    @Bean
    public HibernateJpaSessionFactoryBean sessionFactory(EntityManagerFactory emf) {
         HibernateJpaSessionFactoryBean factory = new HibernateJpaSessionFactoryBean();
         factory.setEntityManagerFactory(emf);
         return factory;
    }
}

That way you have both an EntityManagerFactory and a SessionFactory.

UPDATE: As of Hibernate 5 the SessionFactory actually extends the EntityManagerFactory. So to obtain a SessionFactory you can simply cast the EntityManagerFactory to it or use the unwrap method to get one.

public class SomeHibernateRepository {

  @PersistenceUnit
  private EntityManagerFactory emf;

  protected SessionFactory getSessionFactory() {
    return emf.unwrap(SessionFactory.class);
  }

}

Assuming you have a class with a main method with @EnableAutoConfiguration you don't need the @EnableTransactionManagement annotation, as that will be enabled by Spring Boot for you. A basic application class in the com.spring.app package should be enough.

@Configuration
@EnableAutoConfiguration
@ComponentScan
public class Application {


    public static void main(String[] args) throws Exception {
        SpringApplication.run(Application.class, args);
    }

} 

Something like that should be enough to have all your classes (including entities and Spring Data based repositories) detected.

UPDATE: These annotations can be replaced with a single @SpringBootApplication in more recent versions of Spring Boot.

@SpringBootApplication
public class Application {

    public static void main(String[] args) throws Exception {
        SpringApplication.run(Application.class, args);
    }
} 

I would also suggest removing the commons-dbcp dependency as that would allow Spring Boot to configure the faster and more robust HikariCP implementation.

Spring Boot, Spring Data JPA with multiple DataSources

I checked the source code you provided on GitHub. There were several mistakes / typos in the configuration.

In CustomerDbConfig / OrderDbConfig you should refer to customerEntityManager and packages should point at existing packages:

@Configuration
@EnableJpaRepositories(
    entityManagerFactoryRef = "customerEntityManager",
    transactionManagerRef = "customerTransactionManager",
    basePackages = {"com.mm.boot.multidb.repository.customer"})
public class CustomerDbConfig {

The packages to scan in customerEntityManager and orderEntityManager were both not pointing at proper package:

em.setPackagesToScan("com.mm.boot.multidb.model.customer");

Also the injection of proper EntityManagerFactory did not work. It should be:

@Bean(name = "customerTransactionManager")
public PlatformTransactionManager transactionManager(EntityManagerFactory customerEntityManager){

}

The above was causing the issue and the exception. While providing the name in a @Bean method you are sure you get proper EMF injected.

The last thing I have done was to disable to automatic configuration of JpaRepositories:

@EnableAutoConfiguration(exclude = JpaRepositoriesAutoConfiguration.class)

And with all fixes the application starts as you probably expect!

TransactionRequiredException Executing an update/delete query

The same exception occurred to me in a somewhat different situation. Since I've been searching here for an answer, maybe it'll help somebody.

I my case the exception has been happening because I called the (properly annotated) @Transactional method from a SERVICE CONSTRUCTOR... Since my idea was simply to make this method run at the start, I annotated it as following, and stopped calling in a wrong way. Exception is gone, and code is better :)

@EventListener(ContextRefreshedEvent.class)
@Transactional
public void methodName() {...}

@Transactional import: import org.springframework.transaction.annotation.Transactional;

Spring data jpa- No bean named 'entityManagerFactory' is defined; Injection of autowired dependencies failed

I had this issue after migrating from spring-boot-starter-data-jpa ver. 1.5.7 to 2.0.2 (from old hibernate to hibernate 5.2). In my @Configuration class I injected entityManagerFactory and transactionManager.

//I've got my data source defined in application.yml config file, 
//so there is no need to configure it from java.
@Autowired
DataSource dataSource;

@Bean
public LocalContainerEntityManagerFactoryBean entityManagerFactory() {
    //JpaVendorAdapteradapter can be autowired as well if it's configured in application properties.
    HibernateJpaVendorAdapter vendorAdapter = new HibernateJpaVendorAdapter();
    vendorAdapter.setGenerateDdl(false);

    LocalContainerEntityManagerFactoryBean factory = new LocalContainerEntityManagerFactoryBean();
    factory.setJpaVendorAdapter(vendorAdapter);
    //Add package to scan for entities.
    factory.setPackagesToScan("com.company.domain");
    factory.setDataSource(dataSource);
    return factory;
}

@Bean
public PlatformTransactionManager transactionManager(EntityManagerFactory entityManagerFactory) {
    JpaTransactionManager txManager = new JpaTransactionManager();
    txManager.setEntityManagerFactory(entityManagerFactory);
    return txManager;
}

Also remember to add hibernate-entitymanager dependency to pom.xml otherwise EntityManagerFactory won't be found on classpath:

<dependency>
        <groupId>org.hibernate</groupId>
        <artifactId>hibernate-entitymanager</artifactId>
        <version>5.0.12.Final</version>
</dependency>

java.lang.ClassNotFoundException: org.springframework.core.io.Resource

Right-Click on your project -> Properties -> Deployment Assembly.

On the Left-hand panel Click 'Add' and add the 'Project and External Dependencies'.

'Project and External Dependencies' will have all the spring related jars deployed along with your application

Spring Boot - Cannot determine embedded database driver class for database type NONE

I'd the same problem and excluding the DataSourceAutoConfiguration solved the problem.

@SpringBootApplication
@EnableAutoConfiguration(exclude={DataSourceAutoConfiguration.class})
public class RecommendationEngineWithCassandraApplication {

    public static void main(String[] args) {
        SpringApplication.run(RecommendationEngineWithCassandraApplication.class, args);
    }
}

org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'MyController':

If nothing happens even if you added all the annotation needed, try to add this dependency to your pom.xml, I just faced the same problem and resolved it by adding this one here:

<dependency>
   <groupId>commons-configuration</groupId>
   <artifactId>commons-configuration</artifactId>
   <version>1.9</version>
</dependency>

How to test Spring Data repositories?

If you're using Spring Boot, you can simply use @SpringBootTest to load in your ApplicationContext (which is what your stacktrace is barking at you about). This allows you to autowire in your spring-data repositories. Be sure to add @RunWith(SpringRunner.class) so the spring-specific annotations are picked up:

@RunWith(SpringRunner.class)
@SpringBootTest
public class OrphanManagementTest {

  @Autowired
  private UserRepository userRepository;

  @Test
  public void saveTest() {
    User user = new User("Tom");
    userRepository.save(user);
    Assert.assertNotNull(userRepository.findOne("Tom"));
  }
}

You can read more about testing in spring boot in their docs.

How to resolve "could not execute statement; SQL [n/a]; constraint [numbering];"?

The solution at my end was to explicitly add a JoinColumn annotation like this:

@JoinColumn(name="mapping_type_id")

The column name is usually the table name + "_id" if there is an id field. Additionally, keep in mind which field it should be based on the relationship, OneToMany or ManyToOne.

Hope this helps.

Error creating bean with name 'entityManagerFactory

This sounds like a ClassLoader conflict. I'd bet you have the javax.persistence api 1.x on the classpath somewhere, whereas Spring is trying to access ValidationMode, which was only introduced in JPA 2.0.

Since you use Maven, do mvn dependency:tree, find the artifact:

<dependency>
    <groupId>javax.persistence</groupId>
    <artifactId>persistence-api</artifactId>
    <version>1.0</version>
</dependency>

And remove it from your setup. (See Excluding Dependencies)

AFAIK there is no such general distribution for JPA 2, but you can use this Hibernate-specific version:

<dependency>
    <groupId>org.hibernate.javax.persistence</groupId>
    <artifactId>hibernate-jpa-2.0-api</artifactId>
    <version>1.0.1.Final</version>
</dependency>

OK, since that doesn't work, you still seem to have some JPA-1 version in there somewhere. In a test method, add this code:

System.out.println(EntityManager.class.getProtectionDomain()
                                      .getCodeSource()
                                      .getLocation());

See where that points you and get rid of that artifact.


Ahh, now I finally see the problem. Get rid of this:

<dependency>
    <groupId>org.springframework</groupId>
    <artifactId>spring-jpa</artifactId>
    <version>2.0.8</version>
</dependency>

and replace it with

<dependency>
    <groupId>org.springframework</groupId>
    <artifactId>spring-orm</artifactId>
    <version>3.2.5.RELEASE</version>
</dependency>

On a different note, you should set all test libraries (spring-test, easymock etc.) to

<scope>test</scope>

Launching Spring application Address already in use

In Eclipse, if Spring Tool Suite is installed, you can go to Boot Dashboard and expand local in explorer and right click on the application that is running on port 8080 and stop it before you re run your application.

@Autowired - No qualifying bean of type found for dependency

The thing is that both the application context and the web application context are registered in the WebApplicationContext during server startup. When you run the test you must explicitly tell which contexts to load.

Try this:

@RunWith(SpringJUnit4ClassRunner.class)
@ContextConfiguration(locations = {"classpath:/beans.xml", "/mvc-dispatcher-servlet.xml"})

could not extract ResultSet in hibernate

Another potential cause, for other people coming across the same error message is that this error will occur if you are accessing a table in a different schema from the one you have authenticated with.

In this case you would need to add the schema name to your entity entry:

@Table(name= "catalog", schema = "targetSchemaName")

Spring Data JPA - "No Property Found for Type" Exception

it looks like your custom JpaRepository method name does not match any Variable in your entity classs. Make sure your method name matches a variable in your entity class

for example: you got a variable name called "active" and your custom JpaRepository method says "findByActiveStatus" and since there is no variable called "activeStatus" it will throw"PropertyReferenceException"

UnexpectedRollbackException: Transaction rolled back because it has been marked as rollback-only

The answer of Shyam was right. I already faced with this issue before. It's not a problem, it's a SPRING feature. "Transaction rolled back because it has been marked as rollback-only" is acceptable.

Conclusion

  • USE REQUIRES_NEW if you want to commit what did you do before exception (Local commit)
  • USE REQUIRED if you want to commit only when all processes are done (Global commit) And you just need to ignore "Transaction rolled back because it has been marked as rollback-only" exception. But you need to try-catch out side the caller processNextRegistrationMessage() to have a meaning log.

Let's me explain more detail:

Question: How many Transaction we have? Answer: Only one

Because you config the PROPAGATION is PROPAGATION_REQUIRED so that the @Transaction persist() is using the same transaction with the caller-processNextRegistrationMessage(). Actually, when we get an exception, the Spring will set rollBackOnly for the TransactionManager so the Spring will rollback just only one Transaction.

Question: But we have a try-catch outside (), why does it happen this exception? Answer Because of unique Transaction

  1. When persist() method has an exception
  2. Go to the catch outside

    Spring will set the rollBackOnly to true -> it determine we must 
    rollback the caller (processNextRegistrationMessage) also.
    
  3. The persist() will rollback itself first.

  4. Throw an UnexpectedRollbackException to inform that, we need to rollback the caller also.
  5. The try-catch in run() will catch UnexpectedRollbackException and print the stack trace

Question: Why we change PROPAGATION to REQUIRES_NEW, it works?

Answer: Because now the processNextRegistrationMessage() and persist() are in the different transaction so that they only rollback their transaction.

Thanks

Transaction marked as rollback only: How do I find the cause

disable the transactionmanager in your Bean.xml

<tx:annotation-driven proxy-target-class="true" transaction-manager="transactionManager"/>
    <bean id="transactionManager"
        class="org.springframework.jdbc.datasource.DataSourceTransactionManager">
        <property name="dataSource" ref="dataSource"></property>
    </bean>

comment out these lines, and you'll see the exception causing the rollback ;)

An Authentication object was not found in the SecurityContext - Spring 3.2.2

I encountered the same error while using SpringBoot 2.1.4, along with Spring Security 5 (I believe). After one day of trying everything that Google had to offer, I discovered the cause of error in my case. I had a setup of micro-services, with the Auth server being different from the Resource Server. I had the following lines in my application.yml which prevented 'auto-configuration' despite of having included dependencies spring-boot-starter-security, spring-security-oauth2 and spring-security-jwt. I had included the following in the properties (during development) which caused the error.

spring:
  autoconfigure:
    exclude: org.springframework.boot.autoconfigure.security.servlet.SecurityAutoConfiguration

Commenting it out solved it for me.

#spring:
#  autoconfigure:
#    exclude: org.springframework.boot.autoconfigure.security.servlet.SecurityAutoConfiguration

Hope, it helps someone.

How to load Spring Application Context

Add this at the start of main

ApplicationContext context = new ClassPathXmlApplicationContext("path/to/applicationContext.xml");

JobLauncher launcher=(JobLauncher)context.getBean("launcher");
Job job=(Job)context.getBean("job");

//Get as many beans you want
//Now do the thing you were doing inside test method
StopWatch sw = new StopWatch();
sw.start();
launcher.run(job, jobParameters);
sw.stop();
//initialize the log same way inside main
logger.info(">>> TIME ELAPSED:" + sw.prettyPrint());

Autowiring fails: Not an managed Type

If anyone is strugling with the same problem I solved it by adding @EntityScan in my main class. Just add your model package to the basePackages property.

SQLException: No suitable Driver Found for jdbc:oracle:thin:@//localhost:1521/orcl

i have changed my old path: jdbc:odbc:thin:@localhost:1521:orcl

to new : jdbc:oracle:thin:@//localhost:1521/orcl

and it worked for me.....hurrah!! image

Could not autowire field in spring. why?

I was getting this same error and searching for it led me here. My fix appeared to be simply to add @Component annotation to the implementation of the abstract service.

In this case, that would look like:

import org.springframework.stereotype.Component;

...

@Component
public class ContactServiceImpl implements ContactService {

Injection of autowired dependencies failed; nested exception is org.springframework.beans.factory.BeanCreationException:

Use component scanning as given below, if com.project.action.PasswordHintAction is annotated with stereotype annotations

<context:component-scan base-package="com.project.action"/>

EDIT

I see your problem, in PasswordHintActionTest you are autowiring PasswordHintAction. But you did not create bean configuration for PasswordHintAction to autowire. Add one of stereotype annotation(@Component, @Service, @Controller) to PasswordHintAction like

@Component
public class PasswordHintAction extends BaseAction {
    private static final long serialVersionUID = -4037514607101222025L;
    private String username;

or create xml configuration in applicationcontext.xml like

<bean id="passwordHintAction" class="com.project.action.PasswordHintAction" />

deleted object would be re-saved by cascade (remove deleted object from associations)

You need to remove association on the mapping object:

playList.getPlaylistadMaps().setPlayList(null);
session.delete(playList);

org.springframework.beans.factory.NoSuchBeanDefinitionException: No bean named 'customerService' is defined

Just another possibility: Spring initializes bean by type not by name if you don't define bean with a name, which is ok if you use it by its type:

Producer:

@Service
public void FooServiceImpl implements FooService{}

Consumer:

@Autowired
private FooService fooService;

or

@Autowired
private void setFooService(FooService fooService) {}

but not ok if you use it by name:

ApplicationContext ctx = new ClassPathXmlApplicationContext("applicationContext.xml");
ctx.getBean("fooService");

It would complain: org.springframework.beans.factory.NoSuchBeanDefinitionException: No bean named 'fooService' is defined In this case, assigning name to @Service("fooService") would make it work.

No matching bean of type ... found for dependency

I had a similar issue but I was missing the (@Service or @Component) from the implementation of com.example.my.services.myUser.MyUserServiceImpl

Row was updated or deleted by another transaction (or unsaved-value mapping was incorrect)

First check your imports, when you use session, transaction it should be org.hibernate and remove @Transactinal annotation. and most important in Entity class if you have used @GeneratedValue(strategy=GenerationType.AUTO) or any other then at the time of model object creation/entity object creation should not create id. final conclusion is if you want pass id filed i.e PK then remove @GeneratedValue from entity class.

Annotation @Transactional. How to rollback?

For me rollbackFor was not enough, so I had to put this and it works as expected:

@Transactional(propagation = Propagation.REQUIRED, readOnly = false, rollbackFor = Exception.class)

I hope it helps :-)

org.springframework.beans.factory.BeanCreationException: Error creating bean with name

According to the stack trace, your issue is that your app cannot find org.apache.commons.dbcp.BasicDataSource, as per this line:

java.lang.ClassNotFoundException: org.apache.commons.dbcp.BasicDataSource

I see that you have commons-dbcp in your list of jars, but for whatever reason, your app is not finding the BasicDataSource class in it.

The matching wildcard is strict, but no declaration can be found for element 'tx:annotation-driven'

Make sure that Spring version and xsd version both are same.In my case I am using Spring 4.1.1 so my all xsd should be version *-4.1.xsd

Is this very likely to create a memory leak in Tomcat?

I added the following to @PreDestroy method in my CDI @ApplicationScoped bean, and when I shutdown TomEE 1.6.0 (tomcat7.0.39, as of today), it clears the thread locals.

/*
 * To change this template, choose Tools | Templates
 * and open the template in the editor.
 */
package pf;

import java.lang.ref.WeakReference;
import java.lang.reflect.Array;
import java.lang.reflect.Field;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

/**
 *
 * @author Administrator
 * 
 * google-gson issue # 402: Memory Leak in web application; comment # 25
 * https://code.google.com/p/google-gson/issues/detail?id=402
 */
public class ThreadLocalImmolater {

    final Logger logger = LoggerFactory.getLogger(ThreadLocalImmolater.class);

    Boolean debug;

    public ThreadLocalImmolater() {
        debug = true;
    }

    public Integer immolate() {
        int count = 0;
        try {
            final Field threadLocalsField = Thread.class.getDeclaredField("threadLocals");
            threadLocalsField.setAccessible(true);
            final Field inheritableThreadLocalsField = Thread.class.getDeclaredField("inheritableThreadLocals");
            inheritableThreadLocalsField.setAccessible(true);
            for (final Thread thread : Thread.getAllStackTraces().keySet()) {
                    count += clear(threadLocalsField.get(thread));
                    count += clear(inheritableThreadLocalsField.get(thread));
            }
            logger.info("immolated " + count + " values in ThreadLocals");
        } catch (Exception e) {
            throw new Error("ThreadLocalImmolater.immolate()", e);
        }
        return count;
    }

    private int clear(final Object threadLocalMap) throws Exception {
        if (threadLocalMap == null)
                return 0;
        int count = 0;
        final Field tableField = threadLocalMap.getClass().getDeclaredField("table");
        tableField.setAccessible(true);
        final Object table = tableField.get(threadLocalMap);
        for (int i = 0, length = Array.getLength(table); i < length; ++i) {
            final Object entry = Array.get(table, i);
            if (entry != null) {
                final Object threadLocal = ((WeakReference)entry).get();
                if (threadLocal != null) {
                    log(i, threadLocal);
                    Array.set(table, i, null);
                    ++count;
                }
            }
        }
        return count;
    }

    private void log(int i, final Object threadLocal) {
        if (!debug) {
            return;
        }
        if (threadLocal.getClass() != null &&
            threadLocal.getClass().getEnclosingClass() != null &&
            threadLocal.getClass().getEnclosingClass().getName() != null) {

            logger.info("threadLocalMap(" + i + "): " +
                        threadLocal.getClass().getEnclosingClass().getName());
        }
        else if (threadLocal.getClass() != null &&
                 threadLocal.getClass().getName() != null) {
            logger.info("threadLocalMap(" + i + "): " + threadLocal.getClass().getName());
        }
        else {
            logger.info("threadLocalMap(" + i + "): cannot identify threadlocal class name");
        }
    }

}

No Hibernate Session bound to thread, and configuration does not allow creation of non-transactional one here

after I add the property:

<prop key="hibernate.current_session_context_class">thread</prop> I get the exception like:

org.hibernate.HibernateException: createQuery is not valid without active transaction
org.hibernate.HibernateException: save is not valid without active transaction.

so I think setting that property is not a good solution.

finally I solve "No Hibernate Session bound to thread" problem :

1.<!-- <prop key="hibernate.current_session_context_class">thread</prop> -->
2.add <tx:annotation-driven /> to servlet-context.xml or dispatcher-servlet.xml
3.add @Transactional after @Service and @Repository

Android Fragments and animation

I'd highly suggest you use this instead of creating the animation file because it's a much better solution. Android Studio already provides default animation you can use without creating any new XML file. The animations' names are android.R.anim.slide_in_left and android.R.anim.slide_out_right and you can use them as follows:

fragmentTransaction.setCustomAnimations(android.R.anim.slide_in_left, android.R.anim.slide_out_right);

FragmentManager fragmentManager = getSupportFragmentManager();
FragmentTransaction fragmentTransaction = fragmentManager.beginTransaction();              
fragmentTransaction.setCustomAnimations(android.R.anim.slide_in_left, android.R.anim.slide_out_right);
fragmentManager.addOnBackStackChangedListener(this);
fragmentTransaction.replace(R.id.frame, firstFragment, "h");
fragmentTransaction.addToBackStack("h");
fragmentTransaction.commit();

Output:

enter image description here

JUnit tests pass in Eclipse but fail in Maven Surefire

I had the same issue, but the problem for me was that Java assertions (e.g. assert(num > 0)) were not enabled for Eclipse, but were enabled when running maven.

Therefore running the jUnit tests from Eclipse did not catch trigger the assertion error.

This is made clear when using jUnit 4.11 (as opposed to the older version I was using) because it prints out the assertion error, e.g.

java.lang.AssertionError: null
    at com.company.sdk.components.schema.views.impl.InputViewHandler.<init>(InputViewHandler.java:26)
    at test.com.company.sdk.util.TestSchemaExtractor$MockInputViewHandler.<init>(TestSchemaExtractor.java:31)
    at test.com.company.sdk.util.TestSchemaExtractor.testCreateViewToFieldsMap(TestSchemaExtractor.java:48)

Hibernate - Batch update returned unexpected row count from update: 0 actual row count: 0 expected: 1

In my case, it's because a trigger is triggered before a insert cause, (actually it means to split a big table in several tables using timestamp), and then return null. So I met this problem when I used springboot jpa save() function.

In addition to change the trigger to SET NOCOUNT ON; Mr. TA mentioned above, the solution can also be using native query.

insert into table values(nextval('table_id_seq'), value1)

Error : java.lang.NoSuchMethodError: org.objectweb.asm.ClassWriter.<init>(I)V

I had the same error when initializing Spring on startup, using some different library versions, but everything worked when I got my versions in this order in the classpath (the other libraries in the cp were not important):

  1. asm-3.1.jar
  2. cglib-nodep-2.1_3.jar
  3. asm-attrs-1.5.3.jar

How to inject JPA EntityManager using spring

Yes, although it's full of gotchas, since JPA is a bit peculiar. It's very much worth reading the documentation on injecting JPA EntityManager and EntityManagerFactory, without explicit Spring dependencies in your code:

http://static.springsource.org/spring/docs/3.0.x/spring-framework-reference/html/orm.html#orm-jpa

This allows you to either inject the EntityManagerFactory, or else inject a thread-safe, transactional proxy of an EntityManager directly. The latter makes for simpler code, but means more Spring plumbing is required.

Spring JPA and persistence.xml

Just to confirm though you probably did...

Did you include the

<!--  tell spring to use annotation based congfigurations -->
<context:annotation-config />
<!--  tell spring where to find the beans -->
<context:component-scan base-package="zz.yy.abcd" />

bits in your application context.xml?

Also I'm not so sure you'd be able to use a jta transaction type with this kind of setup? Wouldn't that require a data source managed connection pool? So try RESOURCE_LOCAL instead.

Cause of No suitable driver found for

If you look at your original connection string:

<property name="url" value="jdbc:hsqldb:hsql://localhost"/>

The Hypersonic docs suggest that you're missing an alias after localhost:

http://hsqldb.org/doc/guide/ch04.html

How do I enable MSDTC on SQL Server?

MSDTC must be enabled on both systems, both server and client.
Also, make sure that there isn't a firewall between the systems that blocks RPC.
DTCTest is a nice litt app that helps you to troubleshoot any other problems.

Unit Tests not discovered in Visual Studio 2017

I was facing the same issue, in my case in order to resolved

  1. I opened the windows console (windows key + cmd).
  2. Navigate to the folder where the project was created.
  3. Executed the command "dotnet test" it is basically the same test that visual studio executes but when you run it thru console it allows you to see the complete trace.
  4. I got this error message "TestClass attribute defined on non-public class MSTest.TestController.BaseTest"
  5. So I went to the test case and mark it as public, build again and my tests are being displayed correctly

How to calculate the difference between two dates using PHP?

This is my function. Required PHP >= 5.3.4. It use DateTime class. Very fast, quick and can do the difference between two dates or even the so called "time since".

if(function_exists('grk_Datetime_Since') === FALSE){
    function grk_Datetime_Since($From, $To='', $Prefix='', $Suffix=' ago', $Words=array()){
        #   Est-ce qu'on calcul jusqu'à un moment précis ? Probablement pas, on utilise maintenant
        if(empty($To) === TRUE){
            $To = time();
        }

        #   On va s'assurer que $From est numérique
        if(is_int($From) === FALSE){
            $From = strtotime($From);
        };

        #   On va s'assurer que $To est numérique
        if(is_int($To) === FALSE){
            $To = strtotime($To);
        }

        #   On a une erreur ?
        if($From === FALSE OR $From === -1 OR $To === FALSE OR $To === -1){
            return FALSE;
        }

        #   On va créer deux objets de date
        $From = new DateTime(@date('Y-m-d H:i:s', $From), new DateTimeZone('GMT'));
        $To   = new DateTime(@date('Y-m-d H:i:s', $To), new DateTimeZone('GMT'));

        #   On va calculer la différence entre $From et $To
        if(($Diff = $From->diff($To)) === FALSE){
            return FALSE;
        }

        #   On va merger le tableau des noms (par défaut, anglais)
        $Words = array_merge(array(
            'year'      => 'year',
            'years'     => 'years',
            'month'     => 'month',
            'months'    => 'months',
            'week'      => 'week',
            'weeks'     => 'weeks',
            'day'       => 'day',
            'days'      => 'days',
            'hour'      => 'hour',
            'hours'     => 'hours',
            'minute'    => 'minute',
            'minutes'   => 'minutes',
            'second'    => 'second',
            'seconds'   => 'seconds'
        ), $Words);

        #   On va créer la chaîne maintenant
        if($Diff->y > 1){
            $Text = $Diff->y.' '.$Words['years'];
        } elseif($Diff->y == 1){
            $Text = '1 '.$Words['year'];
        } elseif($Diff->m > 1){
            $Text = $Diff->m.' '.$Words['months'];
        } elseif($Diff->m == 1){
            $Text = '1 '.$Words['month'];
        } elseif($Diff->d > 7){
            $Text = ceil($Diff->d/7).' '.$Words['weeks'];
        } elseif($Diff->d == 7){
            $Text = '1 '.$Words['week'];
        } elseif($Diff->d > 1){
            $Text = $Diff->d.' '.$Words['days'];
        } elseif($Diff->d == 1){
            $Text = '1 '.$Words['day'];
        } elseif($Diff->h > 1){
            $Text = $Diff->h.' '.$Words['hours'];
        } elseif($Diff->h == 1){
            $Text = '1 '.$Words['hour'];
        } elseif($Diff->i > 1){
            $Text = $Diff->i.' '.$Words['minutes'];
        } elseif($Diff->i == 1){
            $Text = '1 '.$Words['minute'];
        } elseif($Diff->s > 1){
            $Text = $Diff->s.' '.$Words['seconds'];
        } else {
            $Text = '1 '.$Words['second'];
        }

        return $Prefix.$Text.$Suffix;
    }
}

Multiple variables in a 'with' statement?

I think you want to do this instead:

from __future__ import with_statement

with open("out.txt","wt") as file_out:
    with open("in.txt") as file_in:
        for line in file_in:
            file_out.write(line)

Writing image to local server

I have an easier solution using fs.readFileSync(./my_local_image_path.jpg)

This is for reading images from Azure Cognative Services's Vision API

const subscriptionKey = 'your_azure_subscrition_key';
const uriBase = // **MUST change your location (mine is 'eastus')**
    'https://eastus.api.cognitive.microsoft.com/vision/v2.0/analyze';

// Request parameters.
const params = {
    'visualFeatures': 'Categories,Description,Adult,Faces',
    'maxCandidates': '2',
    'details': 'Celebrities,Landmarks',
    'language': 'en'
};

const options = {
    uri: uriBase,
    qs: params,
    body: fs.readFileSync(./my_local_image_path.jpg),
    headers: {
        'Content-Type': 'application/octet-stream',
        'Ocp-Apim-Subscription-Key' : subscriptionKey
    }
};

request.post(options, (error, response, body) => {
if (error) {
    console.log('Error: ', error);
    return;
}
let jsonString = JSON.stringify(JSON.parse(body), null, '  ');
body = JSON.parse(body);
if (body.code) // err
{
    console.log("AZURE: " + body.message)
}

console.log('Response\n' + jsonString);

Check whether a path is valid

private bool IsValidPath(string path)
{
    Regex driveCheck = new Regex(@"^[a-zA-Z]:\\$");
    if (!driveCheck.IsMatch(path.Substring(0, 3))) return false;
    string strTheseAreInvalidFileNameChars = new string(Path.GetInvalidPathChars());
    strTheseAreInvalidFileNameChars += @":/?*" + "\"";
    Regex containsABadCharacter = new Regex("[" + Regex.Escape(strTheseAreInvalidFileNameChars) + "]");
    if (containsABadCharacter.IsMatch(path.Substring(3, path.Length - 3)))
        return false;

    DirectoryInfo dir = new DirectoryInfo(Path.GetFullPath(path));
    if (!dir.Exists)
        dir.Create();
    return true;
}

How to SHA1 hash a string in Android?

You don't need andorid for this. You can just do it in simple java.

Have you tried a simple java example and see if this returns the right sha1.

import java.io.UnsupportedEncodingException;
import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;

public class AeSimpleSHA1 {
    private static String convertToHex(byte[] data) {
        StringBuilder buf = new StringBuilder();
        for (byte b : data) {
            int halfbyte = (b >>> 4) & 0x0F;
            int two_halfs = 0;
            do {
                buf.append((0 <= halfbyte) && (halfbyte <= 9) ? (char) ('0' + halfbyte) : (char) ('a' + (halfbyte - 10)));
                halfbyte = b & 0x0F;
            } while (two_halfs++ < 1);
        }
        return buf.toString();
    }

    public static String SHA1(String text) throws NoSuchAlgorithmException, UnsupportedEncodingException {
        MessageDigest md = MessageDigest.getInstance("SHA-1");
        byte[] textBytes = text.getBytes("iso-8859-1");
        md.update(textBytes, 0, textBytes.length);
        byte[] sha1hash = md.digest();
        return convertToHex(sha1hash);
    }
}

Also share what your expected sha1 should be. Maybe ObjectC is doing it wrong.

How to select unique records by SQL

If you only need to remove duplicates then use DISTINCT. GROUP BY should be used to apply aggregate operators to each group

GROUP BY v DISTINCT

C# An established connection was aborted by the software in your host machine

An established connection was aborted by the software in your host machine

That is a boiler-plate error message, it comes out of Windows. The underlying error code is WSAECONNABORTED. Which really doesn't mean more than "connection was aborted". You have to be a bit careful about the "your host machine" part of the phrase. In the vast majority of Windows application programs, it is indeed the host that the desktop app is connected to that aborted the connection. Usually a server somewhere else.

The roles are reversed however when you implement your own server. Now you need to read the error message as "aborted by the application at the other end of the wire". Which is of course not uncommon when you implement a server, client programs that use your server are not unlikely to abort a connection for whatever reason. It can mean that a fire-wall or a proxy terminated the connection but that's not very likely since they typically would not allow the connection to be established in the first place.

You don't really know why a connection was aborted unless you have insight what is going on at the other end of the wire. That's of course hard to come by. If your server is reachable through the Internet then don't discount the possibility that you are being probed by a port scanner. Or your customers, looking for a game cheat.

angular2 manually firing click event on particular element

Angular4

Instead of

    this.renderer.invokeElementMethod(
        this.fileInput.nativeElement, 'dispatchEvent', [event]);

use

    this.fileInput.nativeElement.dispatchEvent(event);

because invokeElementMethod won't be part of the renderer anymore.

Angular2

Use ViewChild with a template variable to get a reference to the file input, then use the Renderer to invoke dispatchEvent to fire the event:

import { Component, Renderer, ElementRef, ViewChild } from '@angular/core';
@Component({
  ...
  template: `
...
<input #fileInput type="file" id="imgFile" (click)="onChange($event)" >
...`
})
class MyComponent {
  @ViewChild('fileInput') fileInput:ElementRef;

  constructor(private renderer:Renderer) {}

  showImageBrowseDlg() {
    // from http://stackoverflow.com/a/32010791/217408
    let event = new MouseEvent('click', {bubbles: true});
    this.renderer.invokeElementMethod(
        this.fileInput.nativeElement, 'dispatchEvent', [event]);
  }
}

Update

Since direct DOM access isn't discouraged anymore by the Angular team this simpler code can be used as well

this.fileInput.nativeElement.click()

See also https://developer.mozilla.org/en-US/docs/Web/API/EventTarget/dispatchEvent

Getting full-size profile picture

I think I use the simplest method to get the full profile picture. You can get full profile picture or you can set the profile picture dimension yourself:

$facebook->api(me?fields=picture.width(800).height(800))

You can set width and height as per your need. Though Facebook doesn't return the exact size asked for, It returns the closest dimension picture available with them.

Using %s in C correctly - very basic level

%s is the representation of an array of char

char string[10] // here is a array of chars, they max length is 10;
char character; // just a char 1 letter/from the ascii map

character = 'a'; // assign 'a' to character
printf("character %c  ",a); //we will display 'a' to stout

so string is an array of char we can assign multiple character per space of memory

string[0]='h';
string[1]='e';
string[2]='l';
string[3]='l';
string[4]='o';
string[5]=(char) 0;//asigning the last element of the 'word' a mark so the string ends

this assignation can be done at initialization like char word="this is a word" // the word array of chars got this string now and is statically defined

toy can also assign values to the array of chars assigning it with functions like strcpy;

strcpy(string,"hello" );

this do the same as the example and automatically add the (char) 0 at the end

so if you print it with %S printf("my string %s",string);

and how string is a array we can just display part of it

//                         the array    one char
printf("first letter of wrd %s     is    :%c ",string,string[1]  );

Django: ImproperlyConfigured: The SECRET_KEY setting must not be empty

I ran into the same problem after restructuring the settings as per the instructions from Daniel Greenfield's book Two scoops of Django.

I resolved the issue by setting

os.environ.setdefault("DJANGO_SETTINGS_MODULE", "project_name.settings.local")

in manage.py and wsgi.py.

Update:

In the above solution, local is the file name (settings/local.py) inside my settings folder, which holds the settings for my local environment.

Another way to resolve this issue is to keep all your common settings inside settings/base.py and then create 3 separate settings files for your production, staging and dev environments.

Your settings folder will look like:

settings/
    __init__.py
    base.py
    local.py
    prod.py
    stage.py

and keep the following code in your settings/__init__.py

from .base import *

env_name = os.getenv('ENV_NAME', 'local')

if env_name == 'prod':
    from .prod import *
elif env_name == 'stage':
    from .stage import *
else:
    from .local import *

Error in Swift class: Property not initialized at super.init call

From the docs

Safety check 1

A designated initializer must ensure that all of the properties introduced by its class are initialized before it delegates up to a superclass initializer.


Why do we need a safety check like this?

To answer this lets go though the initialization process in swift.

Two-Phase Initialization

Class initialization in Swift is a two-phase process. In the first phase, each stored property is assigned an initial value by the class that introduced it. Once the initial state for every stored property has been determined, the second phase begins, and each class is given the opportunity to customize its stored properties further before the new instance is considered ready for use.

The use of a two-phase initialization process makes initialization safe, while still giving complete flexibility to each class in a class hierarchy. Two-phase initialization prevents property values from being accessed before they are initialized, and prevents property values from being set to a different value by another initializer unexpectedly.

So, to make sure the two step initialization process is done as defined above, there are four safety checks, one of them is,

Safety check 1

A designated initializer must ensure that all of the properties introduced by its class are initialized before it delegates up to a superclass initializer.

Now, the two phase initialization never talks about order, but this safety check, introduces super.init to be ordered, after the initialization of all the properties.

Safety check 1 might seem irrelevant as, Two-phase initialization prevents property values from being accessed before they are initialized can be satisfied, without this safety check 1.

Like in this sample

class Shape {
    var name: String
    var sides : Int
    init(sides:Int, named: String) {
        self.sides = sides
        self.name = named
    }
}

class Triangle: Shape {
    var hypotenuse: Int
    init(hypotenuse:Int) {
        super.init(sides: 3, named: "Triangle") 
        self.hypotenuse = hypotenuse
    }
}

Triangle.init has initialized, every property before being used. So Safety check 1 seems irrelevant,

But then there could be another scenario, a little bit complex,

class Shape {
    var name: String
    var sides : Int
    init(sides:Int, named: String) {
        self.sides = sides
        self.name = named
        printShapeDescription()
    }
    func printShapeDescription() {
        print("Shape Name :\(self.name)")
        print("Sides :\(self.sides)")
    }
}

class Triangle: Shape {
    var hypotenuse: Int
    init(hypotenuse:Int) {
        self.hypotenuse = hypotenuse
        super.init(sides: 3, named: "Triangle")
    }

    override func printShapeDescription() {
        super.printShapeDescription()
        print("Hypotenuse :\(self.hypotenuse)")
    }
}

let triangle = Triangle(hypotenuse: 12)

Output :

Shape Name :Triangle
Sides :3
Hypotenuse :12

Here if we had called the super.init before setting the hypotenuse, the super.init call would then have called the printShapeDescription() and since that has been overridden it would first fallback to Triangle class implementation of printShapeDescription(). The printShapeDescription() of Triangle class access the hypotenuse a non optional property that still has not been initialised. And this is not allowed as Two-phase initialization prevents property values from being accessed before they are initialized

So make sure the Two phase initialization is done as defined, there needs to be a specific order of calling super.init, and that is, after initializing all the properties introduced by self class, thus we need a Safety check 1

Restart pods when configmap updates in Kubernetes?

Signalling a pod on config map update is a feature in the works (https://github.com/kubernetes/kubernetes/issues/22368).

You can always write a custom pid1 that notices the confimap has changed and restarts your app.

You can also eg: mount the same config map in 2 containers, expose a http health check in the second container that fails if the hash of config map contents changes, and shove that as the liveness probe of the first container (because containers in a pod share the same network namespace). The kubelet will restart your first container for you when the probe fails.

Of course if you don't care about which nodes the pods are on, you can simply delete them and the replication controller will "restart" them for you.

How do I check if a PowerShell module is installed?

try {
    Import-Module SomeModule
    Write-Host "Module exists"
} 
catch {
    Write-Host "Module does not exist"
}

It should be pointed out that your cmdlet Import-Module has no terminating error, therefore the exception isnt being caught so no matter what your catch statement will never return the new statement you have written.

(https://docs.microsoft.com/en-us/powershell/module/microsoft.powershell.core/about/about_try_catch_finally?view=powershell-6

From The Above:

"A terminating error stops a statement from running. If PowerShell does not handle a terminating error in some way, PowerShell also stops running the function or script using the current pipeline. In other languages, such as C#, terminating errors are referred to as exceptions. For more information about errors, see about_Errors."

It should be written as:

Try {
    Import-Module SomeModule -Force -Erroraction stop
    Write-Host "yep"
}
Catch {
    Write-Host "nope"
}

Which returns:

nope

And if you really wanted to be thorough you should add in the other suggested cmdlets Get-Module -ListAvailable -Name and Get-Module -Name to be extra cautious, before running other functions/cmdlets. And if its installed from psgallery or elsewhere you could also run a Find-Module cmdlet to see if there is a new version available.

Differences between cookies and sessions?

Google JSESSIONID. This will explain how the Servlet API initially uses URL re-writing and then, if cookies are enabled, cookies to manage sessions.

HTTP is stateless so the client browser must send the id of its session to the server with each request. The server, through whatever means, uses this id to retrieve any data for that session making it available for the lifetime of the request.

How to create windows service from java jar?

[2020 Update]

Actually, after spending some times trying the different option provided here which are quite old, I found that the easiest way to do it was to use a small paid tool built for that purpose : FireDaemon Pro. I was trying to run Selenium standalone server as a service and none of the free option worked instantly.

The tool is quite cheap (50 USD one-time-licence, 30 days trial) and it took me 5 minutes to set up the server service instead of a half a day of reading/troubleshooting. So far, it works like a charm.

I have absolutely no link with FusionPro, this is a pure disinterested advice, but feel free to delete if it violates forum rules.

This app won't run unless you update Google Play Services (via Bazaar)

This app won't run unless you update Google Play Services. I have tried it for such a long much time, but still I didn't get the map... Only a blank screen is appearing, even if I modified my Google Play Service given by the below comment..


Check your play services manifest file and check the version code for the APK file com.google.android.gms. In the below, it is "3136110". Download these APK files and install from a DOS prompt, but before installation run your target emulator.

package="com.google.android.gms"
android:versionCode="3136110"
android:versionName="3.1.36 (673201-10)

I got these APK files from this link.

Reading string from input with space character?

#include<stdio.h>
int main()
{
   char name[100];
   printf("Enter your name: ");
   scanf("%[^\n]s",name);
   printf("Your Name is: %s",name);
   return 0;
}

Intel HAXM installation error - This computer does not support Intel Virtualization Technology (VT-x)

I already tried all of the possible solutions on stackoverflow and didn't work What I tried:

  1. Disable Hyper-V in windows feature
  2. Disable Hyper-V with command
  3. Disable Device Guard
  4. etc etc Above solution still give me information about Hyper-V in System Information and the HAXM still failed to install.

But finally I found the solution, you have to disable Hyper-V from System Configuration:

  1. Open System Configuration
  2. Click Service tab
  3. Uncheck all of Hyper-V related

Check System Information then Hyper-V is off now

how to mysqldump remote db from local machine

One can invoke mysqldump locally against a remote server.

Example that worked for me:

mysqldump -h hostname-of-the-server -u mysql_user -p database_name > file.sql

I followed the mysqldump documentation on connection options.

Wait for Angular 2 to load/resolve model before rendering view/template

A nice solution that I've found is to do on UI something like:

<div *ngIf="vendorServicePricing && quantityPricing && service">
 ...Your page...
</div

Only when: vendorServicePricing, quantityPricing and service are loaded the page is rendered.

Xamarin 2.0 vs Appcelerator Titanium vs PhoneGap

Overview

As reported by Tim Anderson

Cross-platform development is a big deal, and will continue to be so until a day comes when everyone uses the same platform. Android? HTML? WebKit? iOS? Windows? Xamarin? Titanum? PhoneGap? Corona? ecc.

Sometimes I hear it said that there are essentially two approaches to cross-platform mobile apps. You can either use an embedded browser control and write a web app wrapped as a native app, as in Adobe PhoneGap/Cordova or the similar approach taken by Sencha, or you can use a cross-platform tool that creates native apps, such as Xamarin Studio, Appcelerator Titanium, or Embarcardero FireMonkey.

Within the second category though, there is diversity. In particular, they vary concerning the extent to which they abstract the user interface.

Here is the trade-off. If you design your cross-platform framework you can have your application work almost the same way on every platform. If you are sharing the UI design across all platforms, it is hard to make your design feel equally right in all cases. It might be better to take the approach adopted by most games, using a design that is distinctive to your app and make a virtue of its consistency across platforms, even though it does not have the native look and feel on any platform.

edit Xamarin v3 in 2014 started offering choice of Xamarin.Forms as well as pure native that still follows the philosophy mentioned here (took liberty of inline edit because such a great answer)

Xamarin Studio on the other hand makes no attempt to provide a shared GUI framework:

We don’t try to provide a user interface abstraction layer that works across all the platforms. We think that’s a bad approach that leads to lowest common denominator user interfaces. (Nat Friedman to Tim Anderson)

This is right; but the downside is the effort involved in maintaining two or more user interface designs for your app.

Comparison about PhoneGap and Titanium it's well reported in Kevin Whinnery blog.

PhoneGap

The purpose of PhoneGap is to allow HTML-based web applications to be deployed and installed as native applications. PhoneGap web applications are wrapped in a native application shell, and can be installed via the native app stores for multiple platforms. Additionally, PhoneGap strives to provide a common native API set which is typically unavailable to web applications, such as basic camera access, device contacts, and sensors not already exposed in the browser.

To develop PhoneGap applications, developers will create HTML, CSS, and JavaScript files in a local directory, much like developing a static website. Approaching native-quality UI performance in the browser is a non-trivial task - Sencha employs a large team of web programming experts dedicated full-time to solving this problem. Even so, on most platforms, in most browsers today, reaching native-quality UI performance and responsiveness is simply not possible, even with a framework as advanced as Sencha Touch. Is the browser already “good enough” though? It depends on your requirements and sensibilities, but it is unquestionably less good than native UI. Sometimes much worse, depending on the browser.

PhoneGap is not as truly cross-platform as one might believe, not all features are equally supported on all platforms.

  • Javascript is not an application scale programming language, too many global scope interactions, different libraries don't often co-exist nicely. We spent many hours trying to get knockout.js and jQuery.mobile play well together, and we still have problems.

  • Fragmented landscape for frameworks and libraries. Too many choices, and too many are not mature enough.

  • Strangely enough, for the needs of our app, decent performance could be achieved (not with jQuery.Mobile, though). We tried jqMobi (not very mature, but fast).

  • Very limited capability for interaction with other apps or cdevice capabilities, and this would not be cross-platform anyway, as there aren't any standards in HTML5 except for a few, like geolocation, camera and local databases.

by Karl Waclawek

Appcelerator Titanium

The goal of Titanium Mobile is to provide a high level, cross-platform JavaScript runtime and API for mobile development (today we support iOS, Android and Windows Phone. Titanium actually has more in common with MacRuby/Hot Cocoa, PHP, or node.js than it does with PhoneGap, Adobe AIR, Corona, or Rhomobile. Titanium is built on two assertions about mobile development: - There is a core of mobile development APIs which can be normalized across platforms. These areas should be targeted for code reuse. - There are platform-specific APIs, UI conventions, and features which developers should incorporate when developing for that platform. Platform-specific code should exist for these use cases to provide the best possible experience.

So for those reasons, Titanium is not an attempt at “write once, run everywhere”. Same as Xamarin.

Titanium are going to do a further step in the direction similar to that of Xamarin. In practice, they will do two layers of different depths: the layer Titanium (in JS), which gives you a bee JS-of-Titanium. If you want to go more low-level, have created an additional layer (called Hyperloop), where (always with JS) to call you back directly to native APIs of SO

Xamarin (+ MVVMCross)

AZDevelop.net

Xamarin (originally a division of Novell) in the last 18 months has brought to market its own IDE and snap-in for Visual Studio. The underlining premise of Mono is to create disparate mobile applications using C# while maintaining native UI development strategies.

In addition to creating a visual design platform to develop native applications, they have integrated testing suites, incorporated native library support and a Nuget style component store. Recently they provided iOS visual design through their IDE freeing the developer from opening XCode. In Visual Studio all three platforms are now supported and a cloud testing suite is on the horizon.

From the get go, Xamarin has provided a rich Android visual design experience. I have yet to download or open Eclipse or any other IDE besides Xamarin. What is truly amazing is that I am able to use LINQ to work with collections as well as create custom delegates and events that free me from objective-C and Java limitations. Many of the libraries I have been spoiled with, like Newtonsoft JSON.Net, work perfectly in all three environments.

In my opinion there are several HUGE advantages including

  • native performance
  • easier to read code (IMO)
  • testability
  • shared code between client and server
  • support (although Xam could do better on bugzilla)

Upgrade for me is use Xamarin and MVVMCross combined. It's still quite a new framework, but it's born from experience of several other frameworks (such as MvvmLight and monocross) and it's now been used in at several released cross platform projects.

Conclusion

My choice after knowing all these framwework, was to select development tool based on product needs. In general, however if you start to use a tool with which you feel comfortable (even if it requires a higher initial overhead) after you'll use it forever.

I chose Xamarin + MVVMCross and I must say to be happy with this choice. I'm not afraid of approach Native SDK for software updates or seeing limited functionality of a system or the most trivial thing a feature graphics. Write code fairly structured (DDD + SOA) is very useful to have a core project shared with native C# views implementation.

References and links

What is the OAuth 2.0 Bearer Token exactly?

Bearer Token
A security token with the property that any party in possession of the token (a "bearer") can use the token in any way that any other party in possession of it can. Using a bearer token does not require a bearer to prove possession of cryptographic key material (proof-of-possession).

The Bearer Token is created for you by the Authentication server. When a user authenticates your application (client) the authentication server then goes and generates for you a Token. Bearer Tokens are the predominant type of access token used with OAuth 2.0. A Bearer token basically says "Give the bearer of this token access".

The Bearer Token is normally some kind of opaque value created by the authentication server. It isn't random; it is created based upon the user giving you access and the client your application getting access.

In order to access an API for example you need to use an Access Token. Access tokens are short lived (around an hour). You use the bearer token to get a new Access token. To get an access token you send the Authentication server this bearer token along with your client id. This way the server knows that the application using the bearer token is the same application that the bearer token was created for. Example: I can't just take a bearer token created for your application and use it with my application it wont work because it wasn't generated for me.

Google Refresh token looks something like this: 1/mZ1edKKACtPAb7zGlwSzvs72PvhAbGmB8K1ZrGxpcNM

copied from comment: I don't think there are any restrictions on the bearer tokens you supply. Only thing I can think of is that its nice to allow more than one. For example a user can authenticate the application up to 30 times and the old bearer tokens will still work. oh and if one hasn't been used for say 6 months I would remove it from your system. It's your authentication server that will have to generate them and validate them so how it's formatted is up to you.

Update:

A Bearer Token is set in the Authorization header of every Inline Action HTTP Request. For example:

POST /rsvp?eventId=123 HTTP/1.1
Host: events-organizer.com
Authorization: Bearer AbCdEf123456
Content-Type: application/x-www-form-urlencoded
User-Agent: Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/1.0 (KHTML, like Gecko; Gmail Actions)

rsvpStatus=YES

The string "AbCdEf123456" in the example above is the bearer authorization token. This is a cryptographic token produced by the authentication server. All bearer tokens sent with actions have the issue field, with the audience field specifying the sender domain as a URL of the form https://. For example, if the email is from [email protected], the audience is https://example.com.

If using bearer tokens, verify that the request is coming from the authentication server and is intended for the the sender domain. If the token doesn't verify, the service should respond to the request with an HTTP response code 401 (Unauthorized).

Bearer Tokens are part of the OAuth V2 standard and widely adopted by many APIs.

SELECT INTO USING UNION QUERY

select *
into new_table
from table_A
UNION
Select * 
From table_B

This only works if Table_A and Table_B have the same schemas

Bootstrap 3 unable to display glyphicon properly

I ended up switching to Font-Awesome Icons. They are just as good if not better, and all you need to do is link in the font, happy days.

How to configure CORS in a Spring Boot + Spring Security application?

Found an easy solution for Spring-Boot, Spring-Security and Java-based config:

@Configuration
@EnableWebSecurity
@EnableGlobalMethodSecurity(prePostEnabled = true)
public class WebSecurityConfig extends WebSecurityConfigurerAdapter {

    @Override
    protected void configure(HttpSecurity httpSecurity) throws Exception {
        httpSecurity.cors().configurationSource(new CorsConfigurationSource() {
            @Override
            public CorsConfiguration getCorsConfiguration(HttpServletRequest request) {
                return new CorsConfiguration().applyPermitDefaultValues();
            }
        });
    }
}

How can I copy columns from one sheet to another with VBA in Excel?

The following works fine for me in Excel 2007. It is simple, and performs a full copy (retains all formatting, etc.):

Sheets("Sheet1").Columns(1).Copy Destination:=Sheets("Sheet2").Columns(2)

"Columns" returns a Range object, and so this is utilizing the "Range.Copy" method. "Destination" is an option to this method - if not provided the default is to copy to the paste buffer. But when provided, it is an easy way to copy.

As when manually copying items in Excel, the size and geometry of the destination must support the range being copied.

Binding a list in @RequestParam

It wasn't obvious to me that although you can accept a Collection as a request param, but on the consumer side you still have to pass in the collection items as comma separated values.

For example if the server side api looks like this:

@PostMapping("/post-topics")
public void handleSubscriptions(@RequestParam("topics") Collection<String> topicStrings) {

    topicStrings.forEach(topic -> System.out.println(topic));
}

Directly passing in a collection to the RestTemplate as a RequestParam like below will result in data corruption

public void subscribeToTopics() {

    List<String> topics = Arrays.asList("first-topic", "second-topic", "third-topic");

    RestTemplate restTemplate = new RestTemplate();
    restTemplate.postForEntity(
            "http://localhost:8088/post-topics?topics={topics}",
            null,
            ResponseEntity.class,
            topics);
}

Instead you can use

public void subscribeToTopics() {

    List<String> topicStrings = Arrays.asList("first-topic", "second-topic", "third-topic");
    String topics = String.join(",",topicStrings);

    RestTemplate restTemplate = new RestTemplate();
    restTemplate.postForEntity(
            "http://localhost:8088/post-topics?topics={topics}",
            null,
            ResponseEntity.class,
            topics);
}

The complete example can be found here, hope it saves someone the headache :)

How do I declare an array with a custom class?

you just need to add a default constructor to your class to look like this:

class name {
  public:
    string first;
    string last;

  name() {
  }

  name(string a, string b){
    first = a;
    last = b;
  }
};

Differences between time complexity and space complexity?

The way in which the amount of storage space required by an algorithm varies with the size of the problem it is solving. Space complexity is normally expressed as an order of magnitude, e.g. O(N^2) means that if the size of the problem (N) doubles then four times as much working storage will be needed.

What data type to use for hashed password field and what length?

Always use a password hashing algorithm: Argon2, scrypt, bcrypt or PBKDF2.

Argon2 won the 2015 password hashing competition. Scrypt, bcrypt and PBKDF2 are older algorithms that are considered less preferred now, but still fundamentally sound, so if your platform doesn't support Argon2 yet, it's ok to use another algorithm for now.

Never store a password directly in a database. Don't encrypt it, either: otherwise, if your site gets breached, the attacker gets the decryption key and so can obtain all passwords. Passwords MUST be hashed.

A password hash has different properties from a hash table hash or a cryptographic hash. Never use an ordinary cryptographic hash such as MD5, SHA-256 or SHA-512 on a password. A password hashing algorithm uses a salt, which is unique (not used for any other user or in anybody else's database). The salt is necessary so that attackers can't just pre-calculate the hashes of common passwords: with a salt, they have to restart the calculation for every account. A password hashing algorithm is intrinsically slow — as slow as you can afford. Slowness hurts the attacker a lot more than you because the attacker has to try many different passwords. For more information, see How to securely hash passwords.

A password hash encodes four pieces of information:

  • An indicator of which algorithm is used. This is necessary for agility: cryptographic recommendations change over time. You need to be able to transition to a new algorithm.
  • A difficulty or hardness indicator. The higher this value, the more computation is needed to calculate the hash. This should be a constant or a global configuration value in the password change function, but it should increase over time as computers get faster, so you need to remember the value for each account. Some algorithms have a single numerical value, others have more parameters there (for example to tune CPU usage and RAM usage separately).
  • The salt. Since the salt must be globally unique, it has to be stored for each account. The salt should be generated randomly on each password change.
  • The hash proper, i.e. the output of the mathematical calculation in the hashing algorithm.

Many libraries include a pair functions that conveniently packages this information as a single string: one that takes the algorithm indicator, the hardness indicator and the password, generates a random salt and returns the full hash string; and one that takes a password and the full hash string as input and returns a boolean indicating whether the password was correct. There's no universal standard, but a common encoding is

$algorithm$parameters$salt$output

where algorithm is a number or a short alphanumeric string encoding the choice of algorithm, parameters is a printable string, and salt and output are encoded in Base64 without terminating =.

16 bytes are enough for the salt and the output. (See e.g. recommendations for Argon2.) Encoded in Base64, that's 21 characters each. The other two parts depend on the algorithm and parameters, but 20–40 characters are typical. That's a total of about 82 ASCII characters (CHAR(82), and no need for Unicode), to which you should add a safety margin if you think it's going to be difficult to enlarge the field later.

If you encode the hash in a binary format, you can get it down to 1 byte for the algorithm, 1–4 bytes for the hardness (if you hard-code some of the parameters), and 16 bytes each for the salt and output, for a total of 37 bytes. Say 40 bytes (BINARY(40)) to have at least a couple of spare bytes. Note that these are 8-bit bytes, not printable characters, in particular the field can include null bytes.

Note that the length of the hash is completely unrelated to the length of the password.

Node.js + Nginx - What now?

We can easily setup a Nodejs app by Nginx acting as a reverse proxy.
The following configuration assumes the NodeJS application is running on 127.0.0.1:8080,

  server{
     server_name domain.com sub.domain.com; # multiple domains

     location /{ 
      proxy_pass http://127.0.0.1:8080;  
      proxy_set_header Host $host;
      proxy_pass_request_headers on;  
     }

     location /static/{
       alias /absolute/path/to/static/files; # nginx will handle js/css
     }
   } 

in above setup your Nodejs app will,

  • get HTTP_HOST header where you can apply domain specific logic to serve the response. '
  • Your Application must be managed by a process manager like pm2 or supervisor for handling situations/reusing sockets or resources etc.

  • Setup an error reporting service for getting production errors like sentry or rollbar

NOTE: you can setup logic for handing domain specific request routes, create a middleware for expressjs application

How to declare a Fixed length Array in TypeScript

The Tuple approach :

This solution provides a strict FixedLengthArray (ak.a. SealedArray) type signature based in Tuples.

Syntax example :

// Array containing 3 strings
let foo : FixedLengthArray<[string, string, string]> 

This is the safest approach, considering it prevents accessing indexes out of the boundaries.

Implementation :

type ArrayLengthMutationKeys = 'splice' | 'push' | 'pop' | 'shift' | 'unshift' | number
type ArrayItems<T extends Array<any>> = T extends Array<infer TItems> ? TItems : never
type FixedLengthArray<T extends any[]> =
  Pick<T, Exclude<keyof T, ArrayLengthMutationKeys>>
  & { [Symbol.iterator]: () => IterableIterator< ArrayItems<T> > }

Tests :

var myFixedLengthArray: FixedLengthArray< [string, string, string]>

// Array declaration tests
myFixedLengthArray = [ 'a', 'b', 'c' ]  // ? OK
myFixedLengthArray = [ 'a', 'b', 123 ]  // ? TYPE ERROR
myFixedLengthArray = [ 'a' ]            // ? LENGTH ERROR
myFixedLengthArray = [ 'a', 'b' ]       // ? LENGTH ERROR

// Index assignment tests 
myFixedLengthArray[1] = 'foo'           // ? OK
myFixedLengthArray[1000] = 'foo'        // ? INVALID INDEX ERROR

// Methods that mutate array length
myFixedLengthArray.push('foo')          // ? MISSING METHOD ERROR
myFixedLengthArray.pop()                // ? MISSING METHOD ERROR

// Direct length manipulation
myFixedLengthArray.length = 123         // ? READ-ONLY ERROR

// Destructuring
var [ a ] = myFixedLengthArray          // ? OK
var [ a, b ] = myFixedLengthArray       // ? OK
var [ a, b, c ] = myFixedLengthArray    // ? OK
var [ a, b, c, d ] = myFixedLengthArray // ? INVALID INDEX ERROR

(*) This solution requires the noImplicitAny typescript configuration directive to be enabled in order to work (commonly recommended practice)


The Array(ish) approach :

This solution behaves as an augmentation of the Array type, accepting an additional second parameter(Array length). Is not as strict and safe as the Tuple based solution.

Syntax example :

let foo: FixedLengthArray<string, 3> 

Keep in mind that this approach will not prevent you from accessing an index out of the declared boundaries and set a value on it.

Implementation :

type ArrayLengthMutationKeys = 'splice' | 'push' | 'pop' | 'shift' |  'unshift'
type FixedLengthArray<T, L extends number, TObj = [T, ...Array<T>]> =
  Pick<TObj, Exclude<keyof TObj, ArrayLengthMutationKeys>>
  & {
    readonly length: L 
    [ I : number ] : T
    [Symbol.iterator]: () => IterableIterator<T>   
  }

Tests :

var myFixedLengthArray: FixedLengthArray<string,3>

// Array declaration tests
myFixedLengthArray = [ 'a', 'b', 'c' ]  // ? OK
myFixedLengthArray = [ 'a', 'b', 123 ]  // ? TYPE ERROR
myFixedLengthArray = [ 'a' ]            // ? LENGTH ERROR
myFixedLengthArray = [ 'a', 'b' ]       // ? LENGTH ERROR

// Index assignment tests 
myFixedLengthArray[1] = 'foo'           // ? OK
myFixedLengthArray[1000] = 'foo'        // ? SHOULD FAIL

// Methods that mutate array length
myFixedLengthArray.push('foo')          // ? MISSING METHOD ERROR
myFixedLengthArray.pop()                // ? MISSING METHOD ERROR

// Direct length manipulation
myFixedLengthArray.length = 123         // ? READ-ONLY ERROR

// Destructuring
var [ a ] = myFixedLengthArray          // ? OK
var [ a, b ] = myFixedLengthArray       // ? OK
var [ a, b, c ] = myFixedLengthArray    // ? OK
var [ a, b, c, d ] = myFixedLengthArray // ? SHOULD FAIL

CURRENT_TIMESTAMP in milliseconds

In PostgreSQL you can use :

SELECT extract(epoch from now());

on MySQL :

SELECT unix_timestamp(now());

Creating a pandas DataFrame from columns of other DataFrames with similar indexes

You can use concat:

In [11]: pd.concat([df1['c'], df2['c']], axis=1, keys=['df1', 'df2'])
Out[11]: 
                 df1       df2
2014-01-01       NaN -0.978535
2014-01-02 -0.106510 -0.519239
2014-01-03 -0.846100 -0.313153
2014-01-04 -0.014253 -1.040702
2014-01-05  0.315156 -0.329967
2014-01-06 -0.510577 -0.940901
2014-01-07       NaN -0.024608
2014-01-08       NaN -1.791899

[8 rows x 2 columns]

The axis argument determines the way the DataFrames are stacked:

df1 = pd.DataFrame([1, 2, 3])
df2 = pd.DataFrame(['a', 'b', 'c'])

pd.concat([df1, df2], axis=0)
   0
0  1
1  2
2  3
0  a
1  b
2  c

pd.concat([df1, df2], axis=1)

   0  0
0  1  a
1  2  b
2  3  c

What is the use of rt.jar file in java?

rt.jar contains all of the compiled class files for the base Java Runtime environment. You should not be messing with this jar file.

For MacOS it is called classes.jar and located under /System/Library/Frameworks/<java_version>/Classes . Same not messing with it rule applies there as well :).

http://javahowto.blogspot.com/2006/05/what-does-rtjar-stand-for-in.html

how to call a onclick function in <a> tag?

Use the onclick as an attribute of your a, not part of the href

<a onclick='window.open("lead_data.php?leadid=1", myWin, scrollbars=yes, width=400, height=650);'>1</a>

Fiddle: http://jsfiddle.net/Wt5La/

How to concatenate strings with padding in sqlite

SQLite has a printf function which does exactly that:

SELECT printf('%s-%.2d-%.4d', col1, col2, col3) FROM mytable

How do I set up access control in SVN?

In your svn\repos\YourRepo\conf folder you will find two files, authz and passwd. These are the two you need to adjust.

In the passwd file you need to add some usernames and passwords. I assume you have already done this since you have people using it:

[users]
User1=password1
User2=password2

Then you want to assign permissions accordingly with the authz file:

Create the conceptual groups you want, and add people to it:

[groups]
allaccess = user1
someaccess = user2

Then choose what access they have from both the permissions and project level.

So let's give our "all access" guys all access from the root:

[/]
@allaccess = rw

But only give our "some access" guys read-only access to some lower level project:

[/someproject]
@someaccess = r

You will also find some simple documentation in the authz and passwd files.

How to fix ReferenceError: primordials is not defined in node

I suggest you first make sure NPM install is not your problem. Then you downgrade node and gulp versions. I used node 10.16.1 and gulp 3.9.1.

To downgrade your gulp you can try

npm install gulp@^3.9.1

What Java FTP client library should I use?

Yes, EnterpriseDT's edtFTPj is stable (first released in 2000), has all the features you might need, and is open source as well.

It's used in a bunch of open source projects (as well as in many commercial projects), and is acknowledged to be one of the fastest client libraries around.

As another poster noted, if you do wish to upgrade to SFTP and/or FTPS, it is a simple upgrade path with very few code changes required.

Using jQuery, Restricting File Size Before Uploading

I found that Apache2 (you might want to also check Apache 1.5) has a way to restrict this before uploading by dropping this in your .htaccess file:

LimitRequestBody 2097152

This restricts it to 2 megabytes (2 * 1024 * 1024) on file upload (if I did my byte math properly).

Note when you do this, the Apache error log will generate this entry when you exceed this limit on a form post or get request:

Requested content-length of 4000107 is larger than the configured limit of 2097152

And it will also display this message back in the web browser:

<h1>Request Entity Too Large</h1>

So, if you're doing AJAX form posts with something like the Malsup jQuery Form Plugin, you could trap for the H1 response like this and show an error result.

By the way, the error number returned is 413. So, you could use a directive in your .htaccess file like...

Redirect 413 413.html

...and provide a more graceful error result back.

Skip a submodule during a Maven build

there is now (from 1.1.1 version) a 'skip' flag in pit.

So you can do things like :

    <profile>
        <id>pit</id>
        <build>
            <plugins>
                <plugin>
                    <groupId>org.pitest</groupId>
                    <artifactId>pitest-maven</artifactId>
                    <configuration>
                        <skip>true</skip>
                    </configuration>
                </plugin>
            </plugins>
        </build>
    </profile>

in your module, and pit will skip

[INFO] --- pitest-maven:1.1.3:mutationCoverage (default-cli) @ module-selenium --- [INFO] Skipping project

Remove DEFINER clause from MySQL Dumps

I don't think there is a way to ignore adding DEFINERs to the dump. But there are ways to remove them after the dump file is created.

  1. Open the dump file in a text editor and replace all occurrences of DEFINER=root@localhost with an empty string ""

  2. Edit the dump (or pipe the output) using perl:

    perl -p -i.bak -e "s/DEFINER=\`\w.*\`@\`\d[0-3].*[0-3]\`//g" mydatabase.sql
    
  3. Pipe the output through sed:

    mysqldump ... | sed -e 's/DEFINER[ ]*=[ ]*[^*]*\*/\*/' > triggers_backup.sql
    

How to determine an object's class?

I use the blow function in my GeneralUtils class, check it may be useful

    public String getFieldType(Object o) {
    if (o == null) {
        return "Unable to identify the class name";
    }
    return o.getClass().getName();
}

Is it safe to shallow clone with --depth 1, create commits, and pull updates again?

Note that Git 1.9/2.0 (Q1 2014) has removed that limitation.
See commit 82fba2b, from Nguy?n Thái Ng?c Duy (pclouds):

Now that git supports data transfer from or to a shallow clone, these limitations are not true anymore.

The documentation now reads:

--depth <depth>::

Create a 'shallow' clone with a history truncated to the specified number of revisions.

That stems from commits like 0d7d285, f2c681c, and c29a7b8 which support clone, send-pack /receive-pack with/from shallow clones.
smart-http now supports shallow fetch/clone too.

All the details are in "shallow.c: the 8 steps to select new commits for .git/shallow".

Update June 2015: Git 2.5 will even allow for fetching a single commit!
(Ultimate shallow case)


Update January 2016: Git 2.8 (Mach 2016) now documents officially the practice of getting a minimal history.
See commit 99487cf, commit 9cfde9e (30 Dec 2015), commit 9cfde9e (30 Dec 2015), commit bac5874 (29 Dec 2015), and commit 1de2e44 (28 Dec 2015) by Stephen P. Smith (``).
(Merged by Junio C Hamano -- gitster -- in commit 7e3e80a, 20 Jan 2016)

This is "Documentation/user-manual.txt"

A <<def_shallow_clone,shallow clone>> is created by specifying the git-clone --depth switch.
The depth can later be changed with the git-fetch --depth switch, or full history restored with --unshallow.

Merging inside a <<def_shallow_clone,shallow clone>> will work as long as a merge base is in the recent history.
Otherwise, it will be like merging unrelated histories and may have to result in huge conflicts.
This limitation may make such a repository unsuitable to be used in merge based workflows.

Update 2020:

  • git 2.11.1 introduced option git fetch --shallow-exclude= to prevent fetching all history
  • git 2.11.1 introduced option git fetch --shallow-since= to prevent fetching old commits.

For more on the shallow clone update process, see "How to update a git shallow clone?".


As commented by Richard Michael:

to backfill history: git pull --unshallow

And Olle Härstedt adds in the comments:

To backfill part of the history: git fetch --depth=100.

Gradle: Could not determine java version from '11.0.2'

I had the same problem here. In my case I need to use an old version of JDK and I'm using sdkmanager to manage the versions of JDK, so, I changed the version of the virtual machine to 1.8.

sdk use java 8.0.222.j9-adpt

After that, the app runs as expected here.

Using ffmpeg to encode a high quality video

Make sure the PNGs are fully opaque before creating the video

e.g. with imagemagick, give them a black background:

convert 0.png -background black -flatten +matte 0_opaque.png

From my tests, no bitrate or codec is sufficient to make the video look good if you feed ffmpeg PNGs with transparency

MVC 4 Data Annotations "Display" Attribute

In addition to the other answers, there is a big benefit to using the DisplayAttribute when you want to localize the fields. You can lookup the name in a localization database using the DisplayAttribute and it will use whatever translation you wish.

Also, you can let MVC generate the templates for you by using Html.EditorForModel() and it will generate the correct label for you.

Ultimately, it's up to you. But the MVC is very "Model-centric", which is why data attributes are applied to models, so that metadata exists in a single place. It's not like it's a huge amount of extra typing you have to do.

What's the simplest way to print a Java array?

This is nice to know, however, as for "always check the standard libraries first" I'd never have stumbled upon the trick of Arrays.toString( myarray )

--since I was concentrating on the type of myarray to see how to do this. I didn't want to have to iterate through the thing: I wanted an easy call to make it come out similar to what I see in the Eclipse debugger and myarray.toString() just wasn't doing it.

import java.util.Arrays;
.
.
.
System.out.println( Arrays.toString( myarray ) );

HTML/CSS font color vs span style

Use style. The font tag is deprecated (W3C Wiki).

org.hibernate.exception.ConstraintViolationException: Could not execute JDBC batch update

Your Event.hbm.xml says:

<set name="attendees" cascade="all">
    <key column="attendeeId" />
    <one-to-many class="Attendee" />
</set>

In plain english, this means that the column Attendee.attendeeId is the foreign key for the association attendees and points to the primary key of Event.

When you add those Attendees to the event, hibernate updates the foreign key to express the changed association. Since that same column is also the primary key of Attendee, this violates the primary key constraint.

Since an Attendee's identity and event participation are independent, you should use separate columns for the primary and foreign key.

Edit: The selects might be because you don't appear to have a version property configured, making it impossible for hibernate to know whether the attendees already exists in the database (they might have been loaded in a previous session), so hibernate emits selects to check. As for the update statements, it was probably easier to implement that way. If you want to get rid of these separate updates, I recommend mapping the association from both ends, and declare the Event-end as inverse.

Google Chrome forcing download of "f.txt" file

This issue appears to be causing ongoing consternation, so I will attempt to give a clearer answer than the previously posted answers, which only contain partial hints as to what's happening.

  • Some time around the summer of 2014, IT Security Engineer Michele Spagnuolo (apparently employed at Google Zurich) developed a proof-of-concept exploit and supporting tool called Rosetta Flash that demonstrated a way for hackers to run malicious Flash SWF files from a remote domain in a manner which tricks browsers into thinking it came from the same domain the user was currently browsing. This allows bypassing of the "same-origin policy" and can permit hackers a variety of exploits. You can read the details here: https://miki.it/blog/2014/7/8/abusing-jsonp-with-rosetta-flash/
    • Known affected browsers: Chrome, IE
    • Possibly unaffected browsers: Firefox
  • Adobe has released at least 5 different fixes over the past year while trying to comprehensively fix this vulnerability, but various major websites also introduced their own fixes earlier on in order to prevent mass vulnerability to their userbases. Among the sites to do so: Google, Youtube, Facebook, Github, and others. One component of the ad-hoc mitigation implemented by these website owners was to force the HTTP Header Content-Disposition: attachment; filename=f.txt on the returns from JSONP endpoints. This has the annoyance of causing the browser to automatically download a file called f.txt that you didn't request—but it is far better than your browser automatically running a possibly malicious Flash file.
  • In conclusion, the websites you were visiting when this file spontaneously downloaded are not bad or malicious, but some domain serving content on their pages (usually ads) had content with this exploit inside it. Note that this issue will be random and intermittent in nature because even visiting the same pages consecutively will often produce different ad content. For example, the advertisement domain ad.doubleclick.net probably serves out hundreds of thousands of different ads and only a small percentage likely contain malicious content. This is why various users online are confused thinking they fixed the issue or somehow affected it by uninstalling this program or running that scan, when in fact it is all unrelated. The f.txt download just means you were protected from a recent potential attack with this exploit and you should have no reason to believe you were compromised in any way.
  • The only way I'm aware that you could stop this f.txt file from being downloaded again in the future would be to block the most common domains that appear to be serving this exploit. I've put a short list below of some of the ones implicated in various posts. If you wanted to block these domains from touching your computer, you could add them to your firewall or alternatively you could use the HOSTS file technique described in the second section of this link: http://www.chromefans.org/chrome-tutorial/how-to-block-a-website-in-google-chrome.htm
  • Short list of domains you could block (by no means a comprehensive list). Most of these are highly associated with adware and malware:
    • ad.doubleclick.net
    • adclick.g.doubleclick.net
    • secure-us.imrworldwide.com
    • d.turn.com
    • ad.turn.com
    • secure.insightexpressai.com
    • core.insightexpressai.com

TypeError: 'str' does not support the buffer interface

You can not serialize a Python 3 'string' to bytes without explict conversion to some encoding.

outfile.write(plaintext.encode('utf-8'))

is possibly what you want. Also this works for both python 2.x and 3.x.

How do I increment a DOS variable in a FOR /F loop?

The problem with your code snippet is the way variables are expanded. Variable expansion is usually done when a statement is first read. In your case the whole FOR loop and its block is read and all variables, except the loop variables are expanded to their current value.

This means %c% in your echo %%i, %c% expanded instantly and so is actually used as echo %%i, 1 in each loop iteration.

So what you need is the delayed variable expansion. Find some good explanation about it here.

Variables that should be delay expanded are referenced with !VARIABLE! instead of %VARIABLE%. But you need to activate this feature with setlocal ENABLEDELAYEDEXPANSION and reset it with a matching endlocal.

Your modified code would look something like that:

set TEXT_T="myfile.txt"

set /a c=1

setlocal ENABLEDELAYEDEXPANSION

FOR /F "tokens=1 usebackq" %%i in (%TEXT_T%) do (
  set /a c=c+1

  echo %%i, !c!
)

endlocal

How can I set the request header for curl?

Sometimes changing the header is not enough, some sites check the referer as well:

curl -v \
     -H 'Host: restapi.some-site.com' \
     -H 'Connection: keep-alive' \
     -H 'Accept: text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8' \
     -H 'Accept-Language: en-GB,en-US;q=0.8,en;q=0.6' \
     -e localhost \
     -A 'Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/29.0.1547.65 Safari/537.36' \
     'http://restapi.some-site.com/getsomething?argument=value&argument2=value'

In this example the referer (-e or --referer in curl) is 'localhost'.

How to set CATALINA_HOME variable in windows 7?

In order to set CATALINA_HOME:

  1. First, unzip and paste the apache-tomcat-7.1.100 folder in your C:// drive folder.

NOTE: Do not place your apache tomcat folder within any other folder or drive, place it directly in C:// drive folder only. (I did this mistake and none of the above-mentioned solutions were working).

  1. Open environment variable dialog box (windows key+ pause-break key --> advanced setting).

  2. Add a new variable name as "CATALINA_HOME" and add the variable path as "C://apache-tomcat-7.1.100"(as in my case), in System Variables.

  3. Edit PATH variable name add "%CATALINA_HOME%\bin" and press OK.

  4. Close the window and it will be saved.

  5. Open Command Prompt window and type command- "%CATALINA_HOME%\bin\startup.bat" to run and start the Tomcat server.

  6. END!

Quadratic and cubic regression in Excel

You need to use an undocumented trick with Excel's LINEST function:

=LINEST(known_y's, [known_x's], [const], [stats])

Background

A regular linear regression is calculated (with your data) as:

=LINEST(B2:B21,A2:A21)

which returns a single value, the linear slope (m) according to the formula:

enter image description here

which for your data:

enter image description here

is:

enter image description here

Undocumented trick Number 1

You can also use Excel to calculate a regression with a formula that uses an exponent for x different from 1, e.g. x1.2:

enter image description here

using the formula:

=LINEST(B2:B21, A2:A21^1.2)

which for you data:

enter image description here

is:

enter image description here

You're not limited to one exponent

Excel's LINEST function can also calculate multiple regressions, with different exponents on x at the same time, e.g.:

=LINEST(B2:B21,A2:A21^{1,2})

Note: if locale is set to European (decimal symbol ","), then comma should be replaced by semicolon and backslash, i.e. =LINEST(B2:B21;A2:A21^{1\2})

Now Excel will calculate regressions using both x1 and x2 at the same time:

enter image description here

How to actually do it

The impossibly tricky part there's no obvious way to see the other regression values. In order to do that you need to:

  • select the cell that contains your formula:

    enter image description here

  • extend the selection the left 2 spaces (you need the select to be at least 3 cells wide):

    enter image description here

  • press F2

  • press Ctrl+Shift+Enter

    enter image description here

You will now see your 3 regression constants:

  y = -0.01777539x^2 + 6.864151123x + -591.3531443

Bonus Chatter

I had a function that I wanted to perform a regression using some exponent:

y = m×xk + b

But I didn't know the exponent. So I changed the LINEST function to use a cell reference instead:

=LINEST(B2:B21,A2:A21^F3, true, true)

With Excel then outputting full stats (the 4th paramter to LINEST):

enter image description here

I tell the Solver to maximize R2:

enter image description here

And it can figure out the best exponent. Which for you data:

enter image description here

is:

enter image description here

MongoDb shuts down with Code 100

Please take following steps:

  1. As other friends mentioned, you should make a directory first for your database data to be stored. This folder could be something like:

    C:\mongo-data

  2. From command line navigate to where you have installed mongodb and where mongod.exe resides. In my case the full path is:

    C:\Program Files\MongoDB\Server\3.4\bin

  3. From here run mongod.exe and pass it the path to the folder you created in step one using the flag --dbpath as follows:

    mongod.exe --dbpath "C:\mongo-data"

Please Note: If you are on windows it is necessary to use double-quotes ("") in the above to run properly.

In this way you will get something like the following:

2017-06-14T12:45:59.892+0430 I NETWORK  [thread1] waiting for connections on port 27017

If you use single quotes (' ') on windows, you will get:

2017-06-14T01:13:45.965-0700 I CONTROL  [initandlisten] shutting down with code:100

Hope it helps to resolve the issue.

List of Python format characters

Here you go, Python documentation on old string formatting. tutorial -> 7.1.1. Old String Formatting -> "More information can be found in the [link] section".

Note that you should start using the new string formatting when possible.

How to check list A contains any value from list B?

I use this to count:

int cnt = 0;

foreach (var lA in listA)
{
    if (listB.Contains(lA))
    {
        cnt++;
    }
}

Fatal error: Call to a member function fetch_assoc() on a non-object

Most likely your query failed, and the query call returned a boolean FALSE (or an error object of some sort), which you then try to use as if was a resultset object, causing the error. Try something like var_dump($result) to see what you really got.

Check for errors after EVERY database query call. Even if the query itself is syntactically valid, there's far too many reasons for it to fail anyways - checking for errors every time will save you a lot of grief at some point.

How to convert a string with Unicode encoding to a string of letters

The Apache Commons Lang StringEscapeUtils.unescapeJava() can decode it properly.

import org.apache.commons.lang.StringEscapeUtils;

@Test
public void testUnescapeJava() {
    String sJava="\\u0048\\u0065\\u006C\\u006C\\u006F";
    System.out.println("StringEscapeUtils.unescapeJava(sJava):\n" + StringEscapeUtils.unescapeJava(sJava));
}


 output:
 StringEscapeUtils.unescapeJava(sJava):
 Hello

How to develop a soft keyboard for Android?

first of all you should define an .xml file and make keyboard UI in it:

<?xml version="1.0" encoding="utf-8"?>
<Keyboard xmlns:android="http://schemas.android.com/apk/res/android"
android:keyWidth="12.50%p"
android:keyHeight="7%p">
<!--
android:horizontalGap="0.50%p"
android:verticalGap="0.50%p"
NOTE When we add a horizontalGap in pixels, this interferes with keyWidth in percentages adding up to 100%
NOTE When we have a horizontalGap (on Keyboard level) of 0, this make the horizontalGap (on Key level) to move from after the key to before the key... (I consider this a bug) 
-->
<Row>
    <Key android:codes="-5" android:keyLabel="remove"  android:keyEdgeFlags="left" />
    <Key android:codes="48"    android:keyLabel="0" />
    <Key android:codes="55006" android:keyLabel="clear" />
</Row>
<Row>
    <Key android:codes="49"    android:keyLabel="1"  android:keyEdgeFlags="left" />
    <Key android:codes="50"    android:keyLabel="2" />
    <Key android:codes="51"    android:keyLabel="3" />
</Row>
<Row>
    <Key android:codes="52"    android:keyLabel="4"  android:keyEdgeFlags="left" />
    <Key android:codes="53"    android:keyLabel="5" />
    <Key android:codes="54"    android:keyLabel="6" />
</Row>

<Row>
    <Key android:codes="55"    android:keyLabel="7"  android:keyEdgeFlags="left" />
    <Key android:codes="56"    android:keyLabel="8" />
    <Key android:codes="57"    android:keyLabel="9" />
</Row>

In this example you have 4 rows and in each row you have 3 keys. also you can put an icon in each key you want.

Then you should add xml tag in your activity UI like this:

<android.inputmethodservice.KeyboardView
        android:id="@+id/keyboardview1"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:background="@color/white"
        android:focusable="true"
        android:focusableInTouchMode="true"
        android:visibility="visible" />

Also in your .java activity file you should define the keyboard and assign it to a EditText:

CustomKeyboard mCustomKeyboard1 = new CustomKeyboard(this,
            R.id.keyboardview1, R.xml.horizontal_keyboard);
    mCustomKeyboard1.registerEditText(R.id.inputSearch);

This code asign inputSearch (which is a EditText) to your keyboard.

import android.app.Activity;
import android.inputmethodservice.Keyboard;
import android.inputmethodservice.KeyboardView;
import android.inputmethodservice.KeyboardView.OnKeyboardActionListener;
import android.text.Editable;
import android.text.InputType;
import android.view.MotionEvent;
import android.view.View;
import android.view.View.OnClickListener;
import android.view.View.OnFocusChangeListener;
import android.view.View.OnTouchListener;
import android.view.WindowManager;
import android.view.inputmethod.InputMethodManager;
import android.widget.EditText;


public class CustomKeyboard {

/** A link to the KeyboardView that is used to render this CustomKeyboard. */
private KeyboardView mKeyboardView;
/** A link to the activity that hosts the {@link #mKeyboardView}. */
private Activity mHostActivity;

/** The key (code) handler. */
private OnKeyboardActionListener mOnKeyboardActionListener = new OnKeyboardActionListener() {

    public final static int CodeDelete = -5; // Keyboard.KEYCODE_DELETE
    public final static int CodeCancel = -3; // Keyboard.KEYCODE_CANCEL
    public final static int CodePrev = 55000;
    public final static int CodeAllLeft = 55001;
    public final static int CodeLeft = 55002;
    public final static int CodeRight = 55003;
    public final static int CodeAllRight = 55004;
    public final static int CodeNext = 55005;
    public final static int CodeClear = 55006;

    @Override
    public void onKey(int primaryCode, int[] keyCodes) {
        // NOTE We can say '<Key android:codes="49,50" ... >' in the xml
        // file; all codes come in keyCodes, the first in this list in
        // primaryCode
        // Get the EditText and its Editable
        View focusCurrent = mHostActivity.getWindow().getCurrentFocus();
        if (focusCurrent == null
                || focusCurrent.getClass() != EditText.class)
            return;
        EditText edittext = (EditText) focusCurrent;
        Editable editable = edittext.getText();
        int start = edittext.getSelectionStart();
        // Apply the key to the edittext
        if (primaryCode == CodeCancel) {
            hideCustomKeyboard();
        } else if (primaryCode == CodeDelete) {
            if (editable != null && start > 0)
                editable.delete(start - 1, start);
        } else if (primaryCode == CodeClear) {
            if (editable != null)
                editable.clear();
        } else if (primaryCode == CodeLeft) {
            if (start > 0)
                edittext.setSelection(start - 1);
        } else if (primaryCode == CodeRight) {
            if (start < edittext.length())
                edittext.setSelection(start + 1);
        } else if (primaryCode == CodeAllLeft) {
            edittext.setSelection(0);
        } else if (primaryCode == CodeAllRight) {
            edittext.setSelection(edittext.length());
        } else if (primaryCode == CodePrev) {
            View focusNew = edittext.focusSearch(View.FOCUS_BACKWARD);
            if (focusNew != null)
                focusNew.requestFocus();
        } else if (primaryCode == CodeNext) {
            View focusNew = edittext.focusSearch(View.FOCUS_FORWARD);
            if (focusNew != null)
                focusNew.requestFocus();
        } else { // insert character
            editable.insert(start, Character.toString((char) primaryCode));
        }
    }

    @Override
    public void onPress(int arg0) {
    }

    @Override
    public void onRelease(int primaryCode) {
    }

    @Override
    public void onText(CharSequence text) {
    }

    @Override
    public void swipeDown() {
    }

    @Override
    public void swipeLeft() {
    }

    @Override
    public void swipeRight() {
    }

    @Override
    public void swipeUp() {
    }
};

/**
 * Create a custom keyboard, that uses the KeyboardView (with resource id
 * <var>viewid</var>) of the <var>host</var> activity, and load the keyboard
 * layout from xml file <var>layoutid</var> (see {@link Keyboard} for
 * description). Note that the <var>host</var> activity must have a
 * <var>KeyboardView</var> in its layout (typically aligned with the bottom
 * of the activity). Note that the keyboard layout xml file may include key
 * codes for navigation; see the constants in this class for their values.
 * Note that to enable EditText's to use this custom keyboard, call the
 * {@link #registerEditText(int)}.
 * 
 * @param host
 *            The hosting activity.
 * @param viewid
 *            The id of the KeyboardView.
 * @param layoutid
 *            The id of the xml file containing the keyboard layout.
 */
public CustomKeyboard(Activity host, int viewid, int layoutid) {
    mHostActivity = host;
    mKeyboardView = (KeyboardView) mHostActivity.findViewById(viewid);
    mKeyboardView.setKeyboard(new Keyboard(mHostActivity, layoutid));
    mKeyboardView.setPreviewEnabled(false); // NOTE Do not show the preview
                                            // balloons
    mKeyboardView.setOnKeyboardActionListener(mOnKeyboardActionListener);
    // Hide the standard keyboard initially
    mHostActivity.getWindow().setSoftInputMode(
            WindowManager.LayoutParams.SOFT_INPUT_STATE_ALWAYS_HIDDEN);
}

/** Returns whether the CustomKeyboard is visible. */
public boolean isCustomKeyboardVisible() {
    return mKeyboardView.getVisibility() == View.VISIBLE;
}

/**
 * Make the CustomKeyboard visible, and hide the system keyboard for view v.
 */
public void showCustomKeyboard(View v) {
    mKeyboardView.setVisibility(View.VISIBLE);
    mKeyboardView.setEnabled(true);
    if (v != null)
        ((InputMethodManager) mHostActivity
                .getSystemService(Activity.INPUT_METHOD_SERVICE))
                .hideSoftInputFromWindow(v.getWindowToken(), 0);
}

/** Make the CustomKeyboard invisible. */
public void hideCustomKeyboard() {
    mKeyboardView.setVisibility(View.GONE);
    mKeyboardView.setEnabled(false);
}

/**
 * Register <var>EditText<var> with resource id <var>resid</var> (on the
 * hosting activity) for using this custom keyboard.
 * 
 * @param resid
 *            The resource id of the EditText that registers to the custom
 *            keyboard.
 */
public void registerEditText(int resid) {
    // Find the EditText 'resid'
    EditText edittext = (EditText) mHostActivity.findViewById(resid);
    // Make the custom keyboard appear
    edittext.setOnFocusChangeListener(new OnFocusChangeListener() {
        // NOTE By setting the on focus listener, we can show the custom
        // keyboard when the edit box gets focus, but also hide it when the
        // edit box loses focus
        @Override
        public void onFocusChange(View v, boolean hasFocus) {
            if (hasFocus)
                showCustomKeyboard(v);
            else
                hideCustomKeyboard();
        }
    });
    edittext.setOnClickListener(new OnClickListener() {
        // NOTE By setting the on click listener, we can show the custom
        // keyboard again, by tapping on an edit box that already had focus
        // (but that had the keyboard hidden).
        @Override
        public void onClick(View v) {
            showCustomKeyboard(v);
        }
    });
    // Disable standard keyboard hard way
    // NOTE There is also an easy way:
    // 'edittext.setInputType(InputType.TYPE_NULL)' (but you will not have a
    // cursor, and no 'edittext.setCursorVisible(true)' doesn't work )
    edittext.setOnTouchListener(new OnTouchListener() {
        @Override
        public boolean onTouch(View v, MotionEvent event) {
            EditText edittext = (EditText) v;
            int inType = edittext.getInputType(); // Backup the input type
            edittext.setInputType(InputType.TYPE_NULL); // Disable standard
                                                        // keyboard
            edittext.onTouchEvent(event); // Call native handler
            edittext.setInputType(inType); // Restore input type
            return true; // Consume touch event
        }
    });
    // Disable spell check (hex strings look like words to Android)
    edittext.setInputType(edittext.getInputType()
            | InputType.TYPE_TEXT_FLAG_NO_SUGGESTIONS);
}

}

// NOTE How can we change the background color of some keys (like the
// shift/ctrl/alt)?
// NOTE What does android:keyEdgeFlags do/mean

Django -- Template tag in {% if %} block

You shouldn't use the double-bracket {{ }} syntax within if or ifequal statements, you can simply access the variable there like you would in normal python:

{% if title == source %}
   ...
{% endif %}

add scroll bar to table body

This is because you are adding your <tbody> tag before <td> in table you cannot print any data without <td>.

So for that you have to make a <div> say #header with position: fixed;

 header
 {
      position: fixed;
 }

make another <div> which will act as <tbody>

tbody
{
    overflow:scroll;
}

Now your header is fixed and the body will scroll. And the header will remain there.

Which characters need to be escaped when using Bash?

Using the print '%q' technique, we can run a loop to find out which characters are special:

#!/bin/bash
special=$'`!@#$%^&*()-_+={}|[]\\;\':",.<>?/ '
for ((i=0; i < ${#special}; i++)); do
    char="${special:i:1}"
    printf -v q_char '%q' "$char"
    if [[ "$char" != "$q_char" ]]; then
        printf 'Yes - character %s needs to be escaped\n' "$char"
    else
        printf 'No - character %s does not need to be escaped\n' "$char"
    fi
done | sort

It gives this output:

No, character % does not need to be escaped
No, character + does not need to be escaped
No, character - does not need to be escaped
No, character . does not need to be escaped
No, character / does not need to be escaped
No, character : does not need to be escaped
No, character = does not need to be escaped
No, character @ does not need to be escaped
No, character _ does not need to be escaped
Yes, character   needs to be escaped
Yes, character ! needs to be escaped
Yes, character " needs to be escaped
Yes, character # needs to be escaped
Yes, character $ needs to be escaped
Yes, character & needs to be escaped
Yes, character ' needs to be escaped
Yes, character ( needs to be escaped
Yes, character ) needs to be escaped
Yes, character * needs to be escaped
Yes, character , needs to be escaped
Yes, character ; needs to be escaped
Yes, character < needs to be escaped
Yes, character > needs to be escaped
Yes, character ? needs to be escaped
Yes, character [ needs to be escaped
Yes, character \ needs to be escaped
Yes, character ] needs to be escaped
Yes, character ^ needs to be escaped
Yes, character ` needs to be escaped
Yes, character { needs to be escaped
Yes, character | needs to be escaped
Yes, character } needs to be escaped

Some of the results, like , look a little suspicious. Would be interesting to get @CharlesDuffy's inputs on this.

what does Error "Thread 1:EXC_BAD_INSTRUCTION (code=EXC_I386_INVOP, subcode=0x0)" mean?

I got this on WatchOS Sim. The issue persisted even after:

  • Deleting the app
  • Restarting Xcode
  • Deleting Derived Data

...and was finally fixed by "Erase all Content and Settings" in the simulator.

UTF-8 all the way through

I recently discovered that using strtolower() can cause issues where the data is truncated after a special character.

The solution was to use

mb_strtolower($string, 'UTF-8');

mb_ uses MultiByte. It supports more characters but in general is a little slower.

sudo: docker-compose: command not found

Or, just add your binary path into the PATH. At the end of the bashrc:

... 
export PATH=$PATH:/home/user/.local/bin/

save the file and run:

source .bashrc

and the command will work.

SQL error "ORA-01722: invalid number"

An ORA-01722 error occurs when an attempt is made to convert a character string into a number, and the string cannot be converted into a number.

Without seeing your table definition, it looks like you're trying to convert the numeric sequence at the end of your values list to a number, and the spaces that delimit it are throwing this error. But based on the information you've given us, it could be happening on any field (other than the first one).

How to check the input is an integer or not in Java?

If the user input is a String then you can try to parse it as an integer using parseInt method, which throws NumberFormatException when the input is not a valid number string:

try {

    int intValue = Integer.parseInt(stringUserInput));
}(NumberFormatException e) {
    System.out.println("Input is not a valid integer");
}

How do HashTables deal with collisions?

I've heard in my degree classes that a HashTable will place a new entry into the 'next available' bucket if the new Key entry collides with another.

This is actually not true, at least for the Oracle JDK (it is an implementation detail that could vary between different implementations of the API). Instead, each bucket contains a linked list of entries prior to Java 8, and a balanced tree in Java 8 or above.

then how would the HashTable still return the correct Value if this collision occurs when calling for one back with the collision key?

It uses the equals() to find the actually matching entry.

If I implement my own hashing function and use it as part of a look-up table (i.e. a HashMap or Dictionary), what strategies exist for dealing with collisions?

There are various collision handling strategies with different advantages and disadvantages. Wikipedia's entry on hash tables gives a good overview.

generating variable names on fly in python

On an object, you can achieve this with setattr

>>> class A(object): pass
>>> a=A()
>>> setattr(a, "hello1", 5)
>>> a.hello1
5

How to calculate distance between two locations using their longitude and latitude value

public float getMesureLatLang(double lat,double lang) {

    Location loc1 = new Location("");
    loc1.setLatitude(getLatitute());// current latitude
    loc1.setLongitude(getLangitute());//current  Longitude

    Location loc2 = new Location("");
    loc2.setLatitude(lat);
    loc2.setLongitude(lang);

    return loc1.distanceTo(loc2);
 //  return distance(getLatitute(),getLangitute(),lat,lang);
}

How can I use querySelector on to pick an input element by name?

These examples seem a bit inefficient. Try this if you want to act upon the value:

<input id="cta" type="email" placeholder="Enter Email...">
<button onclick="return joinMailingList()">Join</button>

<script>
    const joinMailingList = () => {
        const email = document.querySelector('#cta').value
        console.log(email)
    }
</script>

You will encounter issue if you use this keyword with fat arrow (=>). If you need to do that, go old school:

<script>
    function joinMailingList() {
        const email = document.querySelector('#cta').value
        console.log(email)
    }
</script>

If you are working with password inputs, you should use type="password" so it will display ****** while the user is typing, and it is also more semantic.

The VMware Authorization Service is not running

I've also had this problem recently.

The solution that worked for me was to uninstall vmware, restart windows, and the reinstall vmware.

How can I set the opacity or transparency of a Panel in WinForms?

Don't forget to bring your Panel to the Front when dynamically creating it in the form constructor. Example of transparent panel overlay of tab control.

panel1 = new TransparentPanel();
panel1.BackColor = System.Drawing.Color.Transparent;
panel1.Location = new System.Drawing.Point(0, 0);
panel1.Name = "panel1";
panel1.Size = new System.Drawing.Size(717, 92);
panel1.TabIndex = 0;
tab2.Controls.Add(panel1);
panel1.BringToFront(); 

// <== otherwise the other controls paint over top of the transparent panel

How to implement a tree data-structure in Java?

Please check the below code, where I have used Tree data structures, without using Collection classes. The code may have bugs/improvements but please use this just for reference

package com.datastructure.tree;

public class BinaryTreeWithoutRecursion <T> {

    private TreeNode<T> root;


    public BinaryTreeWithoutRecursion (){
        root = null;
    }


    public void insert(T data){
        root =insert(root, data);

    }

    public TreeNode<T>  insert(TreeNode<T> node, T data ){

        TreeNode<T> newNode = new TreeNode<>();
        newNode.data = data;
        newNode.right = newNode.left = null;

        if(node==null){
            node = newNode;
            return node;
        }
        Queue<TreeNode<T>> queue = new Queue<TreeNode<T>>();
        queue.enque(node);
        while(!queue.isEmpty()){

            TreeNode<T> temp= queue.deque();
            if(temp.left!=null){
                queue.enque(temp.left);
            }else
            {
                temp.left = newNode;

                queue =null;
                return node;
            }
            if(temp.right!=null){
                queue.enque(temp.right);
            }else
            {
                temp.right = newNode;
                queue =null;
                return node;
            }
        }
        queue=null;
        return node; 


    }

    public void inOrderPrint(TreeNode<T> root){
        if(root!=null){

            inOrderPrint(root.left);
            System.out.println(root.data);
            inOrderPrint(root.right);
        }

    }

    public void postOrderPrint(TreeNode<T> root){
        if(root!=null){

            postOrderPrint(root.left);

            postOrderPrint(root.right);
            System.out.println(root.data);
        }

    }

    public void preOrderPrint(){
        preOrderPrint(root);
    }


    public void inOrderPrint(){
        inOrderPrint(root);
    }

    public void postOrderPrint(){
        inOrderPrint(root);
    }


    public void preOrderPrint(TreeNode<T> root){
        if(root!=null){
            System.out.println(root.data);
            preOrderPrint(root.left);
            preOrderPrint(root.right);
        }

    }

    /**
     * @param args
     */
    public static void main(String[] args) {
        // TODO Auto-generated method stub
        BinaryTreeWithoutRecursion <Integer> ls=  new BinaryTreeWithoutRecursion <>();
        ls.insert(1);
        ls.insert(2);
        ls.insert(3);
        ls.insert(4);
        ls.insert(5);
        ls.insert(6);
        ls.insert(7);
        //ls.preOrderPrint();
        ls.inOrderPrint();
        //ls.postOrderPrint();

    }

}

Executing a batch script on Windows shutdown

Create your own shutdown script - called Myshutdown.bat - and do whatever you were going to do in your script and then at the end of it call shutdown /a. Then execute your bat file instead of the normal shutdown.

(See http://www.w7forums.com/threads/run-batch-file-on-shutdown.11860/ for more info.)

Bootstrap change div order with pull-right, pull-left on 3 columns

Try this...

<div class="row">
    <div class="col-xs-3">
        Menu
    </div>
    <div class="col-xs-9">
        <div class="row">
          <div class="col-sm-4 col-sm-push-8">
          Right content
          </div>
          <div class="col-sm-8 col-sm-pull-4">
          Content
          </div>
       </div>
    </div>
</div>

Bootply

How to view log output using docker-compose run?

Update July 1st 2019

docker-compose logs <name-of-service>

From the documentation:

Usage: logs [options] [SERVICE...]

Options:

--no-color Produce monochrome output.

-f, --follow Follow log output.

-t, --timestamps Show timestamps.

--tail="all" Number of lines to show from the end of the logs for each container.

See docker logs

You can start Docker compose in detached mode and attach yourself to the logs of all container later. If you're done watching logs you can detach yourself from the logs output without shutting down your services.

  1. Use docker-compose up -d to start all services in detached mode (-d) (you won't see any logs in detached mode)
  2. Use docker-compose logs -f -t to attach yourself to the logs of all running services, whereas -f means you follow the log output and the -t option gives you timestamps (See Docker reference)
  3. Use Ctrl + z or Ctrl + c to detach yourself from the log output without shutting down your running containers

If you're interested in logs of a single container you can use the docker keyword instead:

  1. Use docker logs -t -f <name-of-service>

Save the output

To save the output to a file you add the following to your logs command:

  1. docker-compose logs -f -t >> myDockerCompose.log

jQuery: enabling/disabling datepicker

This is what worked for me

$("#from").attr("disabled", true);

How to create a simple checkbox in iOS?

Yeah, no checkbox for you in iOS (-:

Here, this is what I did to create a checkbox:

UIButton *checkbox;
BOOL checkBoxSelected;
checkbox = [[UIButton alloc] initWithFrame:CGRectMake(x,y,20,20)];
// 20x20 is the size of the checkbox that you want
// create 2 images sizes 20x20 , one empty square and
// another of the same square with the checkmark in it
// Create 2 UIImages with these new images, then:

[checkbox setBackgroundImage:[UIImage imageNamed:@"notselectedcheckbox.png"]
                    forState:UIControlStateNormal];
[checkbox setBackgroundImage:[UIImage imageNamed:@"selectedcheckbox.png"]
                    forState:UIControlStateSelected];
[checkbox setBackgroundImage:[UIImage imageNamed:@"selectedcheckbox.png"]
                    forState:UIControlStateHighlighted];
checkbox.adjustsImageWhenHighlighted=YES;
[checkbox addTarget:(nullable id) action:(nonnull SEL) forControlEvents:(UIControlEvents)];
[self.view addSubview:checkbox];

Now in the target method do the following:

-(void)checkboxSelected:(id)sender
{
    checkBoxSelected = !checkBoxSelected; /* Toggle */
    [checkbox setSelected:checkBoxSelected];
}

That's it!

Set View Width Programmatically

in code add below line:

spin27.setLayoutParams(new LinearLayout.LayoutParams(200, 120));

How to format Joda-Time DateTime to only mm/dd/yyyy?

I am adding this here even though the other answers are completely acceptable. JodaTime has parsers pre built in DateTimeFormat:

dateTime.toString(DateTimeFormat.longDate());

This is most of the options printed out with their format:

shortDate:         11/3/16
shortDateTime:     11/3/16 4:25 AM
mediumDate:        Nov 3, 2016
mediumDateTime:    Nov 3, 2016 4:25:35 AM
longDate:          November 3, 2016
longDateTime:      November 3, 2016 4:25:35 AM MDT
fullDate:          Thursday, November 3, 2016
fullDateTime:      Thursday, November 3, 2016 4:25:35 AM Mountain Daylight Time

Check if page gets reloaded or refreshed in JavaScript

I found some information here Javascript Detecting Page Refresh

function UnLoadWindow() {
    return 'We strongly recommends NOT closing this window yet.'
}

window.onbeforeunload = UnLoadWindow;

mailto link with HTML body

As you can see in RFC 6068, this is not possible at all:

The special <hfname> "body" indicates that the associated <hfvalue> is the body of the message. The "body" field value is intended to contain the content for the first text/plain body part of the message. The "body" pseudo header field is primarily intended for the generation of short text messages for automatic processing (such as "subscribe" messages for mailing lists), not for general MIME bodies.

Does :before not work on img elements?

Try this code

.button:after {
    content: ""
    position: absolute
    width: 70px
    background-image: url('../../images/frontapp/mid-icon.svg')
    display: inline-block
    background-size: contain
    background-repeat: no-repeat
    right: 0
    bottom: 0
}

index.php not loading by default

After reading all this and trying to fix it, I got a simple solution on ubuntu forum (https://help.ubuntu.com/community/ApacheMySQLPHP). The problem lies with libapache2-mod-php5 module. Thats why the browser downloads the index.php file rather than showing the web page. Do the following. If sudo a2enmod php5 returns module does not exist then the problem is with libapache2-mod-php5. Purge remove the module with command sudo apt-get --purge remove libapache2-mod-php5 Then install it again sudo apt-get install libapache2-mod-php5

Adding local .aar files to Gradle build using "flatDirs" is not working

This line includes all aar and jar files from libs folder:

implementation fileTree(include: ['*.jar', '*.aar'], dir: 'libs/')

Direct casting vs 'as' operator?

If you already know what type it can cast to, use a C-style cast:

var o = (string) iKnowThisIsAString; 

Note that only with a C-style cast can you perform explicit type coercion.

If you don't know whether it's the desired type and you're going to use it if it is, use as keyword:

var s = o as string;
if (s != null) return s.Replace("_","-");

//or for early return:
if (s==null) return;

Note that as will not call any type conversion operators. It will only be non-null if the object is not null and natively of the specified type.

Use ToString() to get a human-readable string representation of any object, even if it can't cast to string.

How to clear cache of Eclipse Indigo

I think you can find the answer you want in these two posts. They are mentioning Flash Builder, but essentially, the talk is about its Eclipse base.

Clear improperly cached compile errors in FlexBuilder: http://blog.aherrman.com/2010/05/clear-improperly-cached-compile-errors.html

How to fix Flash Builder broken workspace: http://va.lent.in/how-to-fix-flash-builder-broken-workspace/

Regex not operator

No, there's no direct not operator. At least not the way you hope for.

You can use a zero-width negative lookahead, however:

\((?!2001)[0-9a-zA-z _\.\-:]*\)

The (?!...) part means "only match if the text following (hence: lookahead) this doesn't (hence: negative) match this. But it doesn't actually consume the characters it matches (hence: zero-width).

There are actually 4 combinations of lookarounds with 2 axes:

  • lookbehind / lookahead : specifies if the characters before or after the point are considered
  • positive / negative : specifies if the characters must match or must not match.

Build tree array from flat array in javascript

You can handle this question with just two line coding:

_(flatArray).forEach(f=>
           {f.nodes=_(flatArray).filter(g=>g.parentId==f.id).value();});

var resultArray=_(flatArray).filter(f=>f.parentId==null).value();

Test Online (see the browser console for created tree)

Requirements:

1- Install lodash 4 (a Javascript library for manipulating objects and collections with performant methods => like the Linq in c#) Lodash

2- A flatArray like below:

    var flatArray=
    [{
      id:1,parentId:null,text:"parent1",nodes:[]
    }
   ,{
      id:2,parentId:null,text:"parent2",nodes:[]
    }
    ,
    {
      id:3,parentId:1,text:"childId3Parent1",nodes:[]
    }
    ,
    {
      id:4,parentId:1,text:"childId4Parent1",nodes:[]
    }
    ,
    {
      id:5,parentId:2,text:"childId5Parent2",nodes:[]
    }
    ,
    {
      id:6,parentId:2,text:"childId6Parent2",nodes:[]
    }
    ,
    {
      id:7,parentId:3,text:"childId7Parent3",nodes:[]
    }
    ,
    {
      id:8,parentId:5,text:"childId8Parent5",nodes:[]
    }];

Thank Mr. Bakhshabadi

Good luck

Array vs. Object efficiency in JavaScript

It depends on usage. If the case is lookup objects is very faster.

Here is a Plunker example to test performance of array and object lookups.

https://plnkr.co/edit/n2expPWVmsdR3zmXvX4C?p=preview

You will see that; Looking up for 5.000 items in 5.000 length array collection, take over 3000 milisecons

However Looking up for 5.000 items in object has 5.000 properties, take only 2 or 3 milisecons

Also making object tree don't make huge difference

Change output format for MySQL command line results to CSV

How about using sed? It comes standard with most (all?) Linux OS.

sed 's/\t/<your_field_delimiter>/g'.

This example uses GNU sed (Linux). For POSIX sed (AIX/Solaris)I believe you would type a literal TAB instead of \t

Example (for CSV output):

#mysql mysql -B -e "select * from user" | while read; do sed 's/\t/,/g'; done

localhost,root,,Y,Y,Y,Y,Y,Y,Y,Y,Y,Y,Y,Y,Y,Y,Y,Y,Y,Y,Y,Y,Y,Y,Y,Y,Y,Y,Y,Y,Y,,,,,0,0,0,0,,
localhost,bill,*2470C0C06DEE42FD1618BB99005ADCA2EC9D1E19,N,N,N,N,N,N,N,N,N,N,N,N,N,N,N,N,N,N,N,N,N,N,N,N,N,N,N,N,N,,,,,0,0,0,0,,
127.0.0.1,root,,Y,Y,Y,Y,Y,Y,Y,Y,Y,Y,Y,Y,Y,Y,Y,Y,Y,Y,Y,Y,Y,Y,Y,Y,Y,Y,Y,Y,Y,,,,,0,0,0,0,,
::1,root,,Y,Y,Y,Y,Y,Y,Y,Y,Y,Y,Y,Y,Y,Y,Y,Y,Y,Y,Y,Y,Y,Y,Y,Y,Y,Y,Y,Y,Y,,,,,0,0,0,0,,
%,jim,*2470C0C06DEE42FD1618BB99005ADCA2EC9D1E19,N,N,N,N,N,N,N,N,N,N,N,N,N,N,N,N,N,N,N,N,N,N,N,N,N,N,N,N,N,,,,,0,0,0,0,,

Positioning <div> element at center of screen

If there are anyone looking for a solution,

I found this,

Its the best solution i found yet!

div {
  width: 100px;
  height: 100px;
  background-color: red;
  position: absolute;
  top:0;
  bottom: 0;
  left: 0;
  right: 0;
  margin: auto;
}

http://dabblet.com/gist/2872671

Hope you enjoy!

How to type in textbox using Selenium WebDriver (Selenium 2) with Java?

You should replace WebDriver wb = new FirefoxDriver(); with driver = new FirefoxDriver(); in your @Before Annotation.

As you are accessing driver object with null or you can make wb reference variable as global variable.

How to JUnit test that two List<E> contain the same elements in the same order?

For excellent code-readability, Fest Assertions has nice support for asserting lists

So in this case, something like:

Assertions.assertThat(returnedComponents).containsExactly("One", "Two", "Three");

Or make the expected list to an array, but I prefer the above approach because it's more clear.

Assertions.assertThat(returnedComponents).containsExactly(argumentComponents.toArray());

GetType used in PowerShell, difference between variables

Select-Object creates a new psobject and copies the properties you requested to it. You can verify this with GetType():

PS > $a.GetType().fullname
System.DayOfWeek

PS > $b.GetType().fullname
System.Management.Automation.PSCustomObject

AngularJs ReferenceError: angular is not defined

I think this will happen if you'll use 'async defer' for (the file that contains the filter) while working with angularjs:

<script src="js/filter.js" type="text/javascript" async defer></script>

if you do, just remove 'async defer'.

Commenting out a set of lines in a shell script

As per this site:

#!/bin/bash
foo=bar
: '
This is a test comment
Author foo bar
Released under GNU 
'

echo "Init..."
# rest of script

Creating a constant Dictionary in C#

Just another idea since I am binding to a winforms combobox:

public enum DateRange {
    [Display(Name = "None")]
    None = 0,
    [Display(Name = "Today")]
    Today = 1,
    [Display(Name = "Tomorrow")]
    Tomorrow = 2,
    [Display(Name = "Yesterday")]
    Yesterday = 3,
    [Display(Name = "Last 7 Days")]
    LastSeven = 4,
    [Display(Name = "Custom")]
    Custom = 99
    };

int something = (int)DateRange.None;

To get the int value from the display name from:

public static class EnumHelper<T>
{
    public static T GetValueFromName(string name)
    {
        var type = typeof(T);
        if (!type.IsEnum) throw new InvalidOperationException();

        foreach (var field in type.GetFields())
        {
            var attribute = Attribute.GetCustomAttribute(field,
                typeof(DisplayAttribute)) as DisplayAttribute;
            if (attribute != null)
            {
                if (attribute.Name == name)
                {
                    return (T)field.GetValue(null);
                }
            }
            else
            {
                if (field.Name == name)
                    return (T)field.GetValue(null);
            }
        }

        throw new ArgumentOutOfRangeException("name");
    }
}

usage:

var z = (int)EnumHelper<DateRange>.GetValueFromName("Last 7 Days");

PHP regular expressions: No ending delimiter '^' found in

PHP regex strings need delimiters. Try:

$numpattern="/^([0-9]+)$/";

Also, note that you have a lower case o, not a zero. In addition, if you're just validating, you don't need the capturing group, and can simplify the regex to /^\d+$/.

Example: http://ideone.com/Ec3zh

See also: PHP - Delimiters

How do I filter date range in DataTables?

Following one is working fine with moments js 2.10 and above

$.fn.dataTableExt.afnFiltering.push(
        function( settings, data, dataIndex ) {
            var min  = $('#min-date').val()
            var max  = $('#max-date').val()
            var createdAt = data[0] || 0; // Our date column in the table
            //createdAt=createdAt.split(" ");
            var startDate   = moment(min, "DD/MM/YYYY");
            var endDate     = moment(max, "DD/MM/YYYY");
            var diffDate = moment(createdAt, "DD/MM/YYYY");
            //console.log(startDate);
            if (
              (min == "" || max == "") ||
              (diffDate.isBetween(startDate, endDate))


            ) {  return true;  }
            return false;

        }
    );

What SOAP client libraries exist for Python, and where is the documentation for them?

Could this help: http://users.skynet.be/pascalbotte/rcx-ws-doc/python.htm#SOAPPY

I found it by searching for wsdl and python, with the rational being, that you would need a wsdl description of a SOAP server to do any useful client wrappers....

How are people unit testing with Entity Framework 6, should you bother?

In order to unit test code that relies on your database you need to setup a database or mock for each and every test.

  1. Having a database (real or mocked) with a single state for all your tests will bite you quickly; you cannot test all records are valid and some aren't from the same data.
  2. Setting up an in-memory database in a OneTimeSetup will have issues where the old database is not cleared down before the next test starts up. This will show as tests working when you run them individually, but failing when you run them all.
  3. A Unit test should ideally only set what affects the test

I am working in an application that has a lot of tables with a lot of connections and some massive Linq blocks. These need testing. A simple grouping missed, or a join that results in more than 1 row will affect results.

To deal with this I have setup a heavy Unit Test Helper that is a lot of work to setup, but enables us to reliably mock the database in any state, and running 48 tests against 55 interconnected tables, with the entire database setup 48 times takes 4.7 seconds.

Here's how:

  1. In the Db context class ensure each table class is set to virtual

    public virtual DbSet<Branch> Branches { get; set; }
    public virtual DbSet<Warehouse> Warehouses { get; set; }
    
  2. In a UnitTestHelper class create a method to setup your database. Each table class is an optional parameter. If not supplied, it will be created through a Make method

    internal static Db Bootstrap(bool onlyMockPassedTables = false, List<Branch> branches = null, List<Products> products = null, List<Warehouses> warehouses = null)
    {
        if (onlyMockPassedTables == false) {
            branches ??= new List<Branch> { MakeBranch() };
            warehouses ??= new List<Warehouse>{ MakeWarehouse() };
        }
    
  3. For each table class, each object in it is mapped to the other lists

        branches?.ForEach(b => {
            b.Warehouse = warehouses.FirstOrDefault(w => w.ID == b.WarehouseID);
        });
    
        warehouses?.ForEach(w => {
            w.Branches = branches.Where(b => b.WarehouseID == w.ID);
        });
    
  4. And add it to the DbContext

         var context = new Db(new DbContextOptionsBuilder<Db>().UseInMemoryDatabase(Guid.NewGuid().ToString()).Options);
         context.Branches.AddRange(branches);
         context.Warehouses.AddRange(warehouses);
         context.SaveChanges();
         return context;
     }
    
  5. Define a list of IDs to make is easier to reuse them and make sure joins are valid

     internal const int BranchID = 1;
     internal const int WarehouseID = 2;
    
  6. Create a Make for each table to setup the most basic, but connected version it can be

     internal static Branch MakeBranch(int id = BranchID, string code = "The branch", int warehouseId = WarehouseID) => new Branch { ID = id, Code = code, WarehouseID = warehouseId };
     internal static Warehouse MakeWarehouse(int id = WarehouseID, string code = "B", string name = "My Big Warehouse") => new Warehouse { ID = id, Code = code, Name = name };
    

It's a lot of work, but it only needs doing once, and then your tests can be very focused because the rest of the database will be setup for it.

[Test]
[TestCase(new string [] {"ABC", "DEF"}, "ABC", ExpectedResult = 1)]
[TestCase(new string [] {"ABC", "BCD"}, "BC", ExpectedResult = 2)]
[TestCase(new string [] {"ABC"}, "EF", ExpectedResult = 0)]
[TestCase(new string[] { "ABC", "DEF" }, "abc", ExpectedResult = 1)]
public int Given_SearchingForBranchByName_Then_ReturnCount(string[] codesInDatabase, string searchString)
{
    // Arrange
    var branches = codesInDatabase.Select(x => UnitTestHelpers.MakeBranch(code: $"qqqq{x}qqq")).ToList();
    var db = UnitTestHelpers.Bootstrap(branches: branches);
    var service = new BranchService(db);

    // Act
    var result = service.SearchByName(searchString);

    // Assert
    return result.Count();
}

For Loop on Lua

By reading online (tables tutorial) it seems tables behave like arrays so you're looking for:

Way1

names = {'John', 'Joe', 'Steve'}
for i = 1,3 do print( names[i] ) end

Way2

names = {'John', 'Joe', 'Steve'}
for k,v in pairs(names) do print(v) end

Way1 uses the table index/key , on your table names each element has a key starting from 1, for example:

names = {'John', 'Joe', 'Steve'}
print( names[1] ) -- prints John

So you just make i go from 1 to 3.

On Way2 instead you specify what table you want to run and assign a variable for its key and value for example:

names = {'John', 'Joe', myKey="myValue" }
for k,v in pairs(names) do print(k,v) end

prints the following:

1   John
2   Joe
myKey   myValue

Access denied for user 'root'@'localhost' (using password: Yes) after password reset LINUX

You can try this solution :-

To have mysql asking you for a password, you also need to specify the -p-option: (try with space between -p and password)

mysql -u root -p new_password

MySQLl access denied

In the Second link someone has commented the same problem.

How to remove duplicate white spaces in string using Java?

Try this - You have to import java.util.regex.*;

    Pattern pattern = Pattern.compile("\\s+");
    Matcher matcher = pattern.matcher(string);
    boolean check = matcher.find();
    String str = matcher.replaceAll(" ");

Where string is your string on which you need to remove duplicate white spaces

Updating state on props change in React Form

From react documentation : https://reactjs.org/blog/2018/06/07/you-probably-dont-need-derived-state.html

Erasing state when props change is an Anti Pattern

Since React 16, componentWillReceiveProps is deprecated. From react documentation, the recommended approach in this case is use

  1. Fully controlled component: the ParentComponent of the ModalBody will own the start_time state. This is not my prefer approach in this case since i think the modal should own this state.
  2. Fully uncontrolled component with a key: this is my prefer approach. An example from react documentation : https://codesandbox.io/s/6v1znlxyxn . You would fully own the start_time state from your ModalBody and use getInitialState just like you have already done. To reset the start_time state, you simply change the key from the ParentComponent

How to configure port for a Spring Boot application

You can set that in application.properties under /src/main/resources/

server.port = 8090

How do you use a variable in a regular expression?

Instead of using the /regex/g syntax, you can construct a new RegExp object:

var replace = "regex";
var re = new RegExp(replace,"g");

You can dynamically create regex objects this way. Then you will do:

"mystring".replace(re, "newstring");

document.all vs. document.getElementById

document.all is very old, you don't have to use it anymore.

To quote Nicholas Zakas:

For instance, when the DOM was young, not all browsers supported getElementById(), and so there was a lot of code that looked like this:

if(document.getElementById){  //DOM
    element = document.getElementById(id);
} else if (document.all) {  //IE
    element = document.all[id];
} else if (document.layers){  //Netscape < 6
    element = document.layers[id];
}

Running a cron every 30 seconds

in dir /etc/cron.d/

new create a file excute_per_30s

* * * * * yourusername  /bin/date >> /home/yourusername/temp/date.txt
* * * * * yourusername sleep 30; /bin/date >> /home/yourusername/temp/date.txt

will run cron every 30 seconds

Creating a Shopping Cart using only HTML/JavaScript

Here's a one page cart written in Javascript with localStorage. Here's a full working pen. Previously found on Codebox

cart.js

var cart = {
  // (A) PROPERTIES
  hPdt : null, // HTML products list
  hItems : null, // HTML current cart
  items : {}, // Current items in cart

  // (B) LOCALSTORAGE CART
  // (B1) SAVE CURRENT CART INTO LOCALSTORAGE
  save : function () {
    localStorage.setItem("cart", JSON.stringify(cart.items));
  },

  // (B2) LOAD CART FROM LOCALSTORAGE
  load : function () {
    cart.items = localStorage.getItem("cart");
    if (cart.items == null) { cart.items = {}; }
    else { cart.items = JSON.parse(cart.items); }
  },

  // (B3) EMPTY ENTIRE CART
  nuke : function () {
    if (confirm("Empty cart?")) {
      cart.items = {};
      localStorage.removeItem("cart");
      cart.list();
    }
  },

  // (C) INITIALIZE
  init : function () {
    // (C1) GET HTML ELEMENTS
    cart.hPdt = document.getElementById("cart-products");
    cart.hItems = document.getElementById("cart-items");

    // (C2) DRAW PRODUCTS LIST
    cart.hPdt.innerHTML = "";
    let p, item, part;
    for (let id in products) {
      // WRAPPER
      p = products[id];
      item = document.createElement("div");
      item.className = "p-item";
      cart.hPdt.appendChild(item);

      // PRODUCT IMAGE
      part = document.createElement("img");
      part.src = "images/" +p.img;
      part.className = "p-img";
      item.appendChild(part);

      // PRODUCT NAME
      part = document.createElement("div");
      part.innerHTML = p.name;
      part.className = "p-name";
      item.appendChild(part);

      // PRODUCT DESCRIPTION
      part = document.createElement("div");
      part.innerHTML = p.desc;
      part.className = "p-desc";
      item.appendChild(part);

      // PRODUCT PRICE
      part = document.createElement("div");
      part.innerHTML = "$" + p.price;
      part.className = "p-price";
      item.appendChild(part);

      // ADD TO CART
      part = document.createElement("input");
      part.type = "button";
      part.value = "Add to Cart";
      part.className = "cart p-add";
      part.onclick = cart.add;
      part.dataset.id = id;
      item.appendChild(part);
    }

    // (C3) LOAD CART FROM PREVIOUS SESSION
    cart.load();

    // (C4) LIST CURRENT CART ITEMS
    cart.list();
  },

  // (D) LIST CURRENT CART ITEMS (IN HTML)
  list : function () {
    // (D1) RESET
    cart.hItems.innerHTML = "";
    let item, part, pdt;
    let empty = true;
    for (let key in cart.items) {
      if(cart.items.hasOwnProperty(key)) { empty = false; break; }
    }

    // (D2) CART IS EMPTY
    if (empty) {
      item = document.createElement("div");
      item.innerHTML = "Cart is empty";
      cart.hItems.appendChild(item);
    }

    // (D3) CART IS NOT EMPTY - LIST ITEMS
    else {
      let p, total = 0, subtotal = 0;
      for (let id in cart.items) {
        // ITEM
        p = products[id];
        item = document.createElement("div");
        item.className = "c-item";
        cart.hItems.appendChild(item);

        // NAME
        part = document.createElement("div");
        part.innerHTML = p.name;
        part.className = "c-name";
        item.appendChild(part);

        // REMOVE
        part = document.createElement("input");
        part.type = "button";
        part.value = "X";
        part.dataset.id = id;
        part.className = "c-del cart";
        part.addEventListener("click", cart.remove);
        item.appendChild(part);

        // QUANTITY
        part = document.createElement("input");
        part.type = "number";
        part.value = cart.items[id];
        part.dataset.id = id;
        part.className = "c-qty";
        part.addEventListener("change", cart.change);
        item.appendChild(part);

        // SUBTOTAL
        subtotal = cart.items[id] * p.price;
        total += subtotal;
      }

      // EMPTY BUTTONS
      item = document.createElement("input");
      item.type = "button";
      item.value = "Empty";
      item.addEventListener("click", cart.nuke);
      item.className = "c-empty cart";
      cart.hItems.appendChild(item);

      // CHECKOUT BUTTONS
      item = document.createElement("input");
      item.type = "button";
      item.value = "Checkout - " + "$" + total;
      item.addEventListener("click", cart.checkout);
      item.className = "c-checkout cart";
      cart.hItems.appendChild(item);
    }
  },

  // (E) ADD ITEM INTO CART
  add : function () {
    if (cart.items[this.dataset.id] == undefined) {
      cart.items[this.dataset.id] = 1;
    } else {
      cart.items[this.dataset.id]++;
    }
    cart.save();
    cart.list();
  },

  // (F) CHANGE QUANTITY
  change : function () {
    if (this.value == 0) {
      delete cart.items[this.dataset.id];
    } else {
      cart.items[this.dataset.id] = this.value;
    }
    cart.save();
    cart.list();
  },
  
  // (G) REMOVE ITEM FROM CART
  remove : function () {
    delete cart.items[this.dataset.id];
    cart.save();
    cart.list();
  },
  
  // (H) CHECKOUT
  checkout : function () {
    // SEND DATA TO SERVER
    // CHECKS
    // SEND AN EMAIL
    // RECORD TO DATABASE
    // PAYMENT
    // WHATEVER IS REQUIRED
    alert("TO DO");

    /*
    var data = new FormData();
    data.append('cart', JSON.stringify(cart.items));
    data.append('products', JSON.stringify(products));
    var xhr = new XMLHttpRequest();
    xhr.open("POST", "SERVER-SCRIPT");
    xhr.onload = function(){ ... };
    xhr.send(data);
    */
  }
};
window.addEventListener("DOMContentLoaded", cart.init);

ISO time (ISO 8601) in Python

Here is what I use to convert to the XSD datetime format:

from datetime import datetime
datetime.now().replace(microsecond=0).isoformat()
# You get your ISO string

I came across this question when looking for the XSD date time format (xs:dateTime). I needed to remove the microseconds from isoformat.

Error : No resource found that matches the given name (at 'icon' with value '@drawable/icon')

You need to add icon.png through visual.

Resouces... / Dravable/ Add ///

Finding the id of a parent div using Jquery

http://jsfiddle.net/qVGwh/6/ Check this

   $("#MadonwebTest").click(function () {
    var id = $("#MadonwebTest").closest("div").attr("id");
    alert(id);
    });

High Quality Image Scaling Library

You can try dotImage, one of my company's products, which includes an object for resampling images that has 18 filter types for various levels of quality.

Typical usage is:

// BiCubic is one technique available in PhotoShop
ResampleCommand resampler = new ResampleCommand(newSize, ResampleMethod.BiCubic);
AtalaImage newImage = resampler.Apply(oldImage).Image;

in addition, dotImage includes 140 some odd image processing commands including many filters similar to those in PhotoShop, if that's what you're looking for.

How do I access an access array item by index in handlebars?

If you want to use dynamic variables

This won't work:

{{#each obj[key]}}
...
{{/each}}

You need to do:

{{#each (lookup obj key)}}
...
{{/each}}

see handlebars lookup helper and handlebars subexpressions.

Draw an X in CSS

You can make a pretty nice X with CSS gradients:

screenshot

demo: https://codepen.io/JasonWoof/pen/rZyRKR

code:

<span class="close-x"></span>
<style>
    .close-x {
        display: inline-block;
        width: 20px;
        height: 20px;
        border: 7px solid #f56b00;
        background:
            linear-gradient(45deg, rgba(0,0,0,0) 0%,rgba(0,0,0,0) 43%,#fff 45%,#fff 55%,rgba(0,0,0,0) 57%,rgba(0,0,0,0) 100%),
            linear-gradient(135deg, #f56b00 0%,#f56b00 43%,#fff 45%,#fff 55%,#f56b00 57%,#f56b00 100%);
    }
</style>

Why can't I use a list as a dict key in python?

The issue is that tuples are immutable, and lists are not. Consider the following

d = {}
li = [1,2,3]
d[li] = 5
li.append(4)

What should d[li] return? Is it the same list? How about d[[1,2,3]]? It has the same values, but is a different list?

Ultimately, there is no satisfactory answer. For example, if the only key that works is the original key, then if you have no reference to that key, you can never again access the value. With every other allowed key, you can construct a key without a reference to the original.

If both of my suggestions work, then you have very different keys that return the same value, which is more than a little surprising. If only the original contents work, then your key will quickly go bad, since lists are made to be modified.

Python logging not outputting anything

Many years later there seems to still be a usability problem with the Python logger. Here's some explanations with examples:

import logging
# This sets the root logger to write to stdout (your console).
# Your script/app needs to call this somewhere at least once.
logging.basicConfig()

# By default the root logger is set to WARNING and all loggers you define
# inherit that value. Here we set the root logger to NOTSET. This logging
# level is automatically inherited by all existing and new sub-loggers
# that do not set a less verbose level.
logging.root.setLevel(logging.NOTSET)

# The following line sets the root logger level as well.
# It's equivalent to both previous statements combined:
logging.basicConfig(level=logging.NOTSET)


# You can either share the `logger` object between all your files or the
# name handle (here `my-app`) and call `logging.getLogger` with it.
# The result is the same.
handle = "my-app"
logger1 = logging.getLogger(handle)
logger2 = logging.getLogger(handle)
# logger1 and logger2 point to the same object:
# (logger1 is logger2) == True


# Convenient methods in order of verbosity from highest to lowest
logger.debug("this will get printed")
logger.info("this will get printed")
logger.warning("this will get printed")
logger.error("this will get printed")
logger.critical("this will get printed")


# In large applications where you would like more control over the logging,
# create sub-loggers from your main application logger.
component_logger = logger.getChild("component-a")
component_logger.info("this will get printed with the prefix `my-app.component-a`")

# If you wish to control the logging levels, you can set the level anywhere 
# in the hierarchy:
#
# - root
#   - my-app
#     - component-a
#

# Example for development:
logger.setLevel(logging.DEBUG)

# If that prints too much, enable debug printing only for your component:
component_logger.setLevel(logging.DEBUG)


# For production you rather want:
logger.setLevel(logging.WARNING)

A common source of confusion comes from a badly initialised root logger. Consider this:

import logging
log = logging.getLogger("myapp")
log.warning("woot")
logging.basicConfig()
log.warning("woot")

Output:

woot
WARNING:myapp:woot

Depending on your runtime environment and logging levels, the first log line (before basic config) might not show up anywhere.

How do you make Git work with IntelliJ?

GitHub for Windows on Windows 7 currently installs Git in a path similar to this:

C:\Users\{username}\AppData\Local\GitHub\PortableGit_93e8418133eb85e81a81e5e19c272776524496c6\bin\git.exe

The guid after PortableGit_ may well be different on your system.

Session variables not working php

I had similar issue and with the cookie domain:

    ini_set('session.cookie_domain', '.domain.com');

the domain was setup wrong so all sessions were ignored because the user cookie was never set right hope this will help someone.

What are callee and caller saved registers?

Caller-Saved (AKA volatile or call-clobbered) Registers

  • The values in caller-saved registers are short term and are not preserved from call to call  
  • It holds temporary (i.e. short term) data

Callee-Saved (AKA non-volatile or call-preserved) Registers

  • The callee-saved registers hold values across calls and are long term
  • It holds non-temporary (i.e. long term) data that is used through multiple functions/calls

Java Object Null Check for method

First you should check if books itself isn't null, then simply check whether books[i] != null:

if(books==null) throw new IllegalArgumentException();

for (int i = 0; i < books.length; i++){
   if(books[i] != null){
        total += books[i].getPrice();
   }
}

Unable to connect to SQL Server instance remotely

I know this is almost 1.5 years old, but I hope I can help someone with what I found.

I had built both a console app and a UWP app and my console connnected fine, but not my UWP. After hours of banging my head against the desk - if it's a intranet server hosting the SQL database you must enable "Private Networks (Client & Server)". It's under Package.appxmanifest and the Capabilities tab.Screenshot

Better way to convert an int to a boolean

Joking aside, if you're only expecting your input integer to be a zero or a one, you should really be checking that this is the case.

int yourInteger = whatever;
bool yourBool;
switch (yourInteger)
{
    case 0: yourBool = false; break;
    case 1: yourBool = true;  break;
    default:
        throw new InvalidOperationException("Integer value is not valid");
}

The out-of-the-box Convert won't check this; nor will yourInteger (==|!=) (0|1).

Android: Clear the back stack

intent.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK | Intent.FLAG_ACTIVITY_CLEAR_TASK);
startActivity(intent);

Exporting result of select statement to CSV format in DB2

According to the docs, you want to export of type del (the default delimiter looks like a comma, which is what you want). See the doc page for more information on the EXPORT command.

PHP - Insert date into mysql

$date=$year."-".$month."-".$day; 
$new_date=date('Y-m-d', strtotime($dob)); 
$status=0;  
$insert_date = date("Y-m-d H:i:s");  
$latest_insert_id=0; 

$insertSql="insert into participationDetail (formId,name,city,emailId,dob,mobile,status,social_media1,social_media2,visa_status,tnc_status,data,gender,insertDate)values('".$formid."','".$name."','".$city."','".$email."','".$new_date."','".$mobile."','".$status."','".$link1."','".$link2."','".$visa_check."','".$tnc_check."','".json_encode($detail_arr,JSON_HEX_APOS)."','".$gender."','".$insert_date."')";

How to fix "Incorrect string value" errors?

Hi i also got this error when i use my online databases from godaddy server i think it has the mysql version of 5.1 or more. but when i do from my localhost server (version 5.7) it was fine after that i created the table from local server and copied to the online server using mysql yog i think the problem is with character set

Screenshot Here

OSX El Capitan: sudo pip install OSError: [Errno: 1] Operation not permitted

pip install --ignore-installed six

This will do the job, then you can try your first command.

Via http://github.com/pypa/pip/issues/3165

Python Pandas replicate rows in dataframe

Appending and concatenating is usually slow in Pandas so I recommend just making a new list of the rows and turning that into a dataframe (unless appending a single row or concatenating a few dataframes).

import pandas as pd

df = pd.DataFrame([
[1,1,'2010-02-05',24924.5,False],
[1,1,'2010-02-12',46039.49,True],
[1,1,'2010-02-19',41595.55,False],
[1,1,'2010-02-26',19403.54,False],
[1,1,'2010-03-05',21827.9,False],
[1,1,'2010-03-12',21043.39,False],
[1,1,'2010-03-19',22136.64,False],
[1,1,'2010-03-26',26229.21,False],
[1,1,'2010-04-02',57258.43,False]
], columns=['Store','Dept','Date','Weekly_Sales','IsHoliday'])

temp_df = []
for row in df.itertuples(index=False):
    if row.IsHoliday:
        temp_df.extend([list(row)]*5)
    else:
        temp_df.append(list(row))

df = pd.DataFrame(temp_df, columns=df.columns)

Ajax post request in laravel 5 return error 500 (Internal Server Error)

Laravel 7.X In bootstrap.js, in axios related code, add:

window.axios.defaults.headers.common['X-CSRF-TOKEN'] = $('meta[name="csrf-token"]').attr('content');

Solved lot of unexplained 500 ajax errors. Of course it's for those who use axios

when do you need .ascx files and how would you use them?

If you have a block of code+html that appears on several pages and is sort of independent of that page (say a block of latest news items), you could copy/paste the code to every page.

It is however better to put that code in its own block and just include that block on every page that needs it. That "block" is an ascx file.

Permanently Set Postgresql Schema Path

(And if you have no admin access to the server)

ALTER ROLE <your_login_role> SET search_path TO a,b,c;

Two important things to know about:

  1. When a schema name is not simple, it needs to be wrapped in double quotes.
  2. The order in which you set default schemas a, b, c matters, as it is also the order in which the schemas will be looked up for tables. So if you have the same table name in more than one schema among the defaults, there will be no ambiguity, the server will always use the table from the first schema you specified for your search_path.

Spring application context external properties?

One way to do it is to add your external config folder to the classpath of the java process. That's how I've often done it in the past.

Read entire file in Scala?

I've been told that Source.fromFile is problematic. Personally, I have had problems opening large files with Source.fromFile and have had to resort to Java InputStreams.

Another interesting solution is using scalax. Here's an example of some well commented code that opens a log file using ManagedResource to open a file with scalax helpers: http://pastie.org/pastes/420714

ASP.NET custom error page - Server.GetLastError() is null

Looking more closely at my web.config set up, one of the comments in this post is very helpful

in asp.net 3.5 sp1 there is a new parameter redirectMode

So we can amend customErrors to add this parameter:

<customErrors mode="RemoteOnly" defaultRedirect="~/errors/GeneralError.aspx" redirectMode="ResponseRewrite" />

the ResponseRewrite mode allows us to load the «Error Page» without redirecting the browser, so the URL stays the same, and importantly for me, exception information is not lost.

Delete/Reset all entries in Core Data?

iOS9+, Swift 2

Delete all objects in all entities

func clearCoreDataStore() {
    let entities = managedObjectModel.entities
    for entity in entities {
        let fetchRequest = NSFetchRequest(entityName: entity.name!)
        let deleteReqest = NSBatchDeleteRequest(fetchRequest: fetchRequest)
        do {
            try context.executeRequest(deleteReqest)
        } catch {
            print(error)
        }
    }
}

Creating pdf files at runtime in c#

iTextSharp is no longer licensed under the MIT/LGPL license. Versions greater than 4.1.6 are licensed under the Affero GPL, meaning you can't even use it in a SaaS (Software as a Service) scenario without licensing your code under the GPL, or a GPL-compatible license.

Other opensource PDF implementations in native .NET include

There's also a couple of Java PDF libraries (like PDFBox) you can convert to .NET using IKVM.

Rebuild all indexes in a Database

DECLARE @Database NVARCHAR(255)   
DECLARE @Table NVARCHAR(255)  
DECLARE @cmd NVARCHAR(1000)  

DECLARE DatabaseCursor CURSOR READ_ONLY FOR  
SELECT name FROM master.sys.databases   
WHERE name NOT IN ('master','msdb','tempdb','model','distribution')  -- databases to exclude
--WHERE name IN ('DB1', 'DB2') -- use this to select specific databases and comment out line above
AND state = 0 -- database is online
AND is_in_standby = 0 -- database is not read only for log shipping
ORDER BY 1  

OPEN DatabaseCursor  

FETCH NEXT FROM DatabaseCursor INTO @Database  
WHILE @@FETCH_STATUS = 0  
BEGIN  

   SET @cmd = 'DECLARE TableCursor CURSOR READ_ONLY FOR SELECT ''['' + table_catalog + ''].['' + table_schema + ''].['' +  
   table_name + '']'' as tableName FROM [' + @Database + '].INFORMATION_SCHEMA.TABLES WHERE table_type = ''BASE TABLE'''   

   -- create table cursor  
   EXEC (@cmd)  
   OPEN TableCursor   

   FETCH NEXT FROM TableCursor INTO @Table   
   WHILE @@FETCH_STATUS = 0   
   BEGIN
      BEGIN TRY   
         SET @cmd = 'ALTER INDEX ALL ON ' + @Table + ' REBUILD' 
         --PRINT @cmd -- uncomment if you want to see commands
         EXEC (@cmd) 
      END TRY
      BEGIN CATCH
         PRINT '---'
         PRINT @cmd
         PRINT ERROR_MESSAGE() 
         PRINT '---'
      END CATCH

      FETCH NEXT FROM TableCursor INTO @Table   
   END   

   CLOSE TableCursor   
   DEALLOCATE TableCursor  

   FETCH NEXT FROM DatabaseCursor INTO @Database  
END  
CLOSE DatabaseCursor   
DEALLOCATE DatabaseCursor

Understanding timedelta

Because timedelta is defined like:

class datetime.timedelta([days,] [seconds,] [microseconds,] [milliseconds,] [minutes,] [hours,] [weeks])

All arguments are optional and default to 0.

You can easily say "Three days and four milliseconds" with optional arguments that way.

>>> datetime.timedelta(days=3, milliseconds=4)
datetime.timedelta(3, 0, 4000)
>>> datetime.timedelta(3, 0, 0, 4) #no need for that.
datetime.timedelta(3, 0, 4000)

And for str casting, it returns a nice formatted value instead of __repr__ to improve readability. From docs:

str(t) Returns a string in the form [D day[s], ][H]H:MM:SS[.UUUUUU], where D is negative for negative t. (5)

>>> datetime.timedelta(seconds = 42).__repr__()
'datetime.timedelta(0, 42)'
>>> datetime.timedelta(seconds = 42).__str__()
'0:00:42'

Checkout documentation:

http://docs.python.org/library/datetime.html#timedelta-objects

How to remove "href" with Jquery?

If you wanted to remove the href, change the cursor and also prevent clicking on it, this should work:

$("a").attr('href', '').css({'cursor': 'pointer', 'pointer-events' : 'none'});

What's the actual use of 'fail' in JUnit test case?

This is how I use the Fail method.

There are three states that your test case can end up in

  1. Passed : The function under test executed successfully and returned data as expected
  2. Not Passed : The function under test executed successfully but the returned data was not as expected
  3. Failed : The function did not execute successfully and this was not

intended (Unlike negative test cases that expect a exception to occur).

If you are using eclipse there three states are indicated by a Green, Blue and red marker respectively.

I use the fail operation for the the third scenario.

e.g. : public Integer add(integer a, Integer b) { return new Integer(a.intValue() + b.intValue())}

  1. Passed Case : a = new Interger(1), b= new Integer(2) and the function returned 3
  2. Not Passed Case: a = new Interger(1), b= new Integer(2) and the function returned soem value other than 3
  3. Failed Case : a =null , b= null and the function throws a NullPointerException

Posting a File and Associated Data to a RESTful WebService preferably as JSON

FormData Objects: Upload Files Using Ajax

XMLHttpRequest Level 2 adds support for the new FormData interface. FormData objects provide a way to easily construct a set of key/value pairs representing form fields and their values, which can then be easily sent using the XMLHttpRequest send() method.

function AjaxFileUpload() {
    var file = document.getElementById("files");
    //var file = fileInput;
    var fd = new FormData();
    fd.append("imageFileData", file);
    var xhr = new XMLHttpRequest();
    xhr.open("POST", '/ws/fileUpload.do');
    xhr.onreadystatechange = function () {
        if (xhr.readyState == 4) {
             alert('success');
        }
        else if (uploadResult == 'success')
             alert('error');
    };
    xhr.send(fd);
}

https://developer.mozilla.org/en-US/docs/Web/API/FormData

Merge two objects with ES6

You can use Object.assign() to merge them into a new object:

_x000D_
_x000D_
const response = {_x000D_
  lat: -51.3303,_x000D_
  lng: 0.39440_x000D_
}_x000D_
_x000D_
const item = {_x000D_
  id: 'qwenhee-9763ae-lenfya',_x000D_
  address: '14-22 Elder St, London, E1 6BT, UK'_x000D_
}_x000D_
_x000D_
const newItem = Object.assign({}, item, { location: response });_x000D_
_x000D_
console.log(newItem );
_x000D_
_x000D_
_x000D_

You can also use object spread, which is a Stage 4 proposal for ECMAScript:

_x000D_
_x000D_
const response = {_x000D_
  lat: -51.3303,_x000D_
  lng: 0.39440_x000D_
}_x000D_
_x000D_
const item = {_x000D_
  id: 'qwenhee-9763ae-lenfya',_x000D_
  address: '14-22 Elder St, London, E1 6BT, UK'_x000D_
}_x000D_
_x000D_
const newItem = { ...item, location: response }; // or { ...response } if you want to clone response as well_x000D_
_x000D_
console.log(newItem );
_x000D_
_x000D_
_x000D_

Mysql command not found in OS X 10.7

I have tried a lot of the suggestions on SO but this is the one that actually worked for me:

sudo sh -c 'echo /usr/local/mysql/bin > /etc/paths.d/mysql'

then you type

mysql

It will prompt you to enter your password.

How to make a script wait for a pressed key?

Cross Platform, Python 2/3 code:

# import sys, os

def wait_key():
    ''' Wait for a key press on the console and return it. '''
    result = None
    if os.name == 'nt':
        import msvcrt
        result = msvcrt.getch()
    else:
        import termios
        fd = sys.stdin.fileno()

        oldterm = termios.tcgetattr(fd)
        newattr = termios.tcgetattr(fd)
        newattr[3] = newattr[3] & ~termios.ICANON & ~termios.ECHO
        termios.tcsetattr(fd, termios.TCSANOW, newattr)

        try:
            result = sys.stdin.read(1)
        except IOError:
            pass
        finally:
            termios.tcsetattr(fd, termios.TCSAFLUSH, oldterm)

    return result

I removed the fctl/non-blocking stuff because it was giving IOErrors and I didn't need it. I'm using this code specifically because I want it to block. ;)

Addendum:

I implemented this in a package on PyPI with a lot of other goodies called console:

>>> from console.utils import wait_key

>>> wait_key()
'h'

Remove all values within one list from another list?

If you don't have repeated values, you could use set difference.

x = set(range(10))
y = x - set([2, 3, 7])
# y = set([0, 1, 4, 5, 6, 8, 9])

and then convert back to list, if needed.

Is it possible to insert multiple rows at a time in an SQLite database?

If you use the Sqlite manager firefox plugin, it supports bulk inserts from INSERT SQL statements.

Infact it doesn't support this, but Sqlite Browser does (works on Windows, OS X, Linux)

How do I change a tab background color when using TabLayout?

You can try this:

<style name="MyCustomTabLayout" parent="Widget.Design.TabLayout">
    <item name="tabBackground">@drawable/background</item>
</style>

In your background xml file:

<selector xmlns:android="http://schemas.android.com/apk/res/android">
    <item android:state_selected="true" android:drawable="@color/white" />
    <item android:drawable="@color/black" />
</selector>

E: gnupg, gnupg2 and gnupg1 do not seem to be installed, but one of them is required for this operation

In your Dockerfile, run this first:

apt-get update && apt-get install -y gnupg2

Speech input for visually impaired users without the need to tap the screen

The only way to get the iOS dictation is to sign up yourself through Nuance: http://dragonmobile.nuancemobiledeveloper.com/ - it's expensive, because it's the best. Presumably, Apple's contract prevents them from exposing an API.

The built in iOS accessibility features allow immobilized users to access dictation (and other keyboard buttons) through tools like VoiceOver and Assistive Touch. It may not be worth reinventing this if your users might be familiar with these tools.

Java and SSL - java.security.NoSuchAlgorithmException

Try javax.net.ssl.keyStorePassword instead of javax.net.ssl.keyPassword: the latter isn't mentioned in the JSSE ref guide.

The algorithms you mention should be there by default using the default security providers. NoSuchAlgorithmExceptions are often cause by other underlying exceptions (file not found, wrong password, wrong keystore type, ...). It's useful to look at the full stack trace.

You could also use -Djavax.net.debug=ssl, or at least -Djavax.net.debug=ssl,keymanager, to get more debugging information, if the information in the stack trace isn't sufficient.

Cannot open include file: 'stdio.h' - Visual Studio Community 2017 - C++ Error

Just in case you don't want to bump Windows SDK to Windows 10 (you could be for example working on an open source project where the decision isn't yours to make), you can solve this problem in a Windows SDK 8.1 project by navigating Tools -> Get Tools and Features... -> Individual Compontents tab and installing the individual components "Windows 8.1 SDK" (under SDKs, libraries and frameworks) and "Windows Universal CRT SDK" (under Compilers, build tools and runtimes):

Force IE9 to emulate IE8. Possible?

Yes. Recent versions of IE (IE8 or above) let you adjust that. Here's how:

  • Fire up Internet Explorer.
  • Click the 'Tools' menu, then click 'Developer Tools'. Alternatively, just press F12.

That should open the Developer Tools window. That window has two menu items that are of interest:

  • Browser Mode. This setting determines the value of the user-agent header sent for every request.
  • Document Mode. This setting determines how the rendering engine renders the page.

More at http://blogs.msdn.com/b/ie/archive/2010/06/16/ie-s-compatibility-features-for-site-developers.aspx

How to create a HTML Cancel button that redirects to a URL

cancel is not a valid value for a type attribute, so the button is probably defaulting to submit and continuing to submit the form. You probably mean type="button".

(The javascript: should be removed though, while it doesn't do any harm, it is an entirely useless label)

You don't have any button-like functionality though, so would be better off with:

<a href="http://stackoverflow.com"> Cancel </a>

… possibly with some CSS to make it look like a button.

How do I read all classes from a Java package in the classpath?

Scannotation and Reflections use class path scanning approach:

Reflections reflections = new Reflections("my.package");
Set<Class<? extends Object>> classes = reflections.getSubTypesOf(Object.class);

Another approach is to use Java Pluggable Annotation Processing API to write annotation processor which will collect all annotated classes at compile time and build the index file for runtime use. This mechanism is implemented in ClassIndex library:

Iterable<Class> classes = ClassIndex.getPackageClasses("my.package");

Print: Entry, ":CFBundleIdentifier", Does Not Exist

When you run npm install command some time internet issue problem, Files in node_modules\react-native\third-party is not properly downloaded so please check this is properly downloaded or not if no please remove node_modules and install it again

then run react-native run-ios command

Python - How do you run a .py file?

Usually you can double click the .py file in Windows explorer to run it. If this doesn't work, you can create a batch file in the same directory with the following contents:

C:\python23\python YOURSCRIPTNAME.py

Then double click that batch file. Or, you can simply run that line in the command prompt while your working directory is the location of your script.

python - if not in list

You better do this syntax

if not (item in mylist):  
    Code inside the if

write a shell script to ssh to a remote machine and execute commands

There is are multiple ways to execute the commands or script in the multiple remote Linux machines. One simple & easiest way is via pssh (parallel ssh program)

pssh: is a program for executing ssh in parallel on a number of hosts. It provides features such as sending input to all of the processes, passing a password to ssh, saving the output to files, and timing out.

Example & Usage:

Connect to host1 and host2, and print "hello, world" from each:

 pssh -i -H "host1 host2" echo "hello, world"

Run commands via a script on multiple servers:

pssh -h hosts.txt -P -I<./commands.sh

Usage & run a command without checking or saving host keys:

pssh -h hostname_ip.txt -x '-q -o StrictHostKeyChecking=no -o PreferredAuthentications=publickey -o PubkeyAuthentication=yes' -i  'uptime; hostname -f'

If the file hosts.txt has a large number of entries, say 100, then the parallelism option may also be set to 100 to ensure that the commands are run concurrently:

pssh -i -h hosts.txt -p 100 -t 0 sleep 10000

Options:
-I: Read input and sends to each ssh process.
-P: Tells pssh to display output as it arrives.
-h: Reads the host's file.
-H : [user@]host[:port] for single-host.
-i: Display standard output and standard error as each host completes
-x args: Passes extra SSH command-line arguments
-o option: Can be used to give options in the format used in the configuration file.(/etc/ssh/ssh_config) (~/.ssh/config)
-p parallelism: Use the given number as the maximum number of concurrent connections
-q Quiet mode: Causes most warning and diagnostic messages to be suppressed.
-t: Make connections time out after the given number of seconds. 0 means pssh will not timeout any connections

When ssh'ing to the remote machine, how to handle when it prompts for RSA fingerprint authentication.

Disable the StrictHostKeyChecking to handle the RSA authentication prompt.
-o StrictHostKeyChecking=no

Source: man pssh

Group query results by month and year in postgresql

I can't believe the accepted answer has so many upvotes -- it's a horrible method.

Here's the correct way to do it, with date_trunc:

   SELECT date_trunc('month', txn_date) AS txn_month, sum(amount) as monthly_sum
     FROM yourtable
 GROUP BY txn_month

It's bad practice but you might be forgiven if you use

 GROUP BY 1

in a very simple query.

You can also use

 GROUP BY date_trunc('month', txn_date)

if you don't want to select the date.

CSS Vertical align does not work with float

Vertical alignment doesn't work with floated elements, indeed. That's because float lifts the element from the normal flow of the document. You might want to use other vertical aligning techniques, like the ones based on transform, display: table, absolute positioning, line-height, js (last resort maybe) or even the plain old html table (maybe the first choice if the content is actually tabular). You'll find that there's a heated debate on this issue.

However, this is how you can vertically align YOUR 3 divs:

.wrap{
    width: 500px;
    overflow:hidden;    
    background: pink;
}

.left {
    width: 150px;       
    margin-right: 10px;
    background: yellow;  
    display:inline-block;
    vertical-align: middle; 
}

.left2 {
    width: 150px;    
    margin-right: 10px;
    background: aqua; 
    display:inline-block;
    vertical-align: middle; 
}

.right{
    width: 150px;
    background: orange;
    display:inline-block;
    vertical-align: middle; 
}

Not sure why you needed both fixed width, display: inline-block and floating.

Cannot declare instance members in a static class in C#

Have you tried using the 'static' storage class similar to?:

public static class employee
{
    static NameValueCollection appSetting = ConfigurationManager.AppSettings;    
}

Converting DateTime format using razor

In general, the written month is escaped as MMM, the 4-digit year as yyyy, so your format string should look like "dd MMM yyyy"

DateTime.ToString("dd MMM yyyy")

Case-Insensitive List Search

Based on Adam Sills answer above - here's a nice clean extensions method for Contains... :)

///----------------------------------------------------------------------
/// <summary>
/// Determines whether the specified list contains the matching string value
/// </summary>
/// <param name="list">The list.</param>
/// <param name="value">The value to match.</param>
/// <param name="ignoreCase">if set to <c>true</c> the case is ignored.</param>
/// <returns>
///   <c>true</c> if the specified list contais the matching string; otherwise, <c>false</c>.
/// </returns>
///----------------------------------------------------------------------
public static bool Contains(this List<string> list, string value, bool ignoreCase = false)
{
    return ignoreCase ?
        list.Any(s => s.Equals(value, StringComparison.OrdinalIgnoreCase)) :
        list.Contains(value);
}

Why do you need to invoke an anonymous function on the same line?

In summary of the previous comments:

function() {
  alert("hello");
}();

when not assigned to a variable, yields a syntax error. The code is parsed as a function statement (or definition), which renders the closing parentheses syntactically incorrect. Adding parentheses around the function portion tells the interpreter (and programmer) that this is a function expression (or invocation), as in

(function() {
  alert("hello");
})();

This is a self-invoking function, meaning it is created anonymously and runs immediately because the invocation happens in the same line where it is declared. This self-invoking function is indicated with the familiar syntax to call a no-argument function, plus added parentheses around the name of the function: (myFunction)();.

There is a good SO discussion JavaScript function syntax.

Byte and char conversion in Java

new String(byteArray, Charset.defaultCharset())

This will convert a byte array to the default charset in java. It may throw exceptions depending on what you supply with the byteArray.

How do I add all new files to SVN

In some shells like fish you can use the ** globbing to do that:

svn add **

How to check Grants Permissions at Run-Time?

original (not mine) post here

For special permissions, such as android.Manifest.permission.PACKAGE_USAGE_STATS used AppOpsManager:
Kotlin

private fun hasPermission(permission:String, permissionAppOpsManager:String): Boolean {
    var granted = false
    if (VERSION.SDK_INT >= VERSION_CODES.M) {
        // requires kitkat
        val appOps = applicationContext!!.getSystemService(Context.APP_OPS_SERVICE) as AppOpsManager

        // requires lollipop
        val mode = appOps.checkOpNoThrow(permissionAppOpsManager,
                              android.os.Process.myUid(), applicationContext!!.packageName)

        if (mode == AppOpsManager.MODE_DEFAULT) {
            granted = applicationContext!!.checkCallingOrSelfPermission(permission) == PackageManager.PERMISSION_GRANTED
        } else {
            granted = mode == AppOpsManager.MODE_ALLOWED
        }
    }

    return granted
}

and anywhere in code:

val permissionAppOpsManager = AppOpsManager.OPSTR_GET_USAGE_STATS
val permission = android.Manifest.permission.PACKAGE_USAGE_STATS
val permissionActivity = Settings.ACTION_USAGE_ACCESS_SETTINGS

if (hasPermission(permission, permissionAppOpsManager)) {
    Timber.i("has permission: $permission")
    // do here what needs permission
} else {
    Timber.e("has no permission: $permission")
    // start activity to get permission
    startActivity(Intent(permissionActivity))
}

Other permissions you can get with TedPermission library

Find objects between two dates MongoDB

db.collection.find({"createdDate":{$gte:new ISODate("2017-04-14T23:59:59Z"),$lte:new ISODate("2017-04-15T23:59:59Z")}}).count();

Replace collection with name of collection you want to execute query

"Undefined reference to" template class constructor

This link explains where you're going wrong:

[35.12] Why can't I separate the definition of my templates class from its declaration and put it inside a .cpp file?

Place the definition of your constructors, destructors methods and whatnot in your header file, and that will correct the problem.

This offers another solution:

How can I avoid linker errors with my template functions?

However this requires you to anticipate how your template will be used and, as a general solution, is counter-intuitive. It does solve the corner case though where you develop a template to be used by some internal mechanism, and you want to police the manner in which it is used.

How to get VM arguments from inside of Java application?

I haven't tried specifically getting the VM settings, but there is a wealth of information in the JMX utilities specifically the MXBean utilities. This would be where I would start. Hopefully you find something there to help you.

The sun website has a bunch on the technology:

http://java.sun.com/javase/6/docs/technotes/guides/management/mxbeans.html

Spring Data JPA and Exists query

It's gotten a lot easier these days!

@Repository
public interface PageRepository extends JpaRepository<Page, UUID> {

    Boolean existsByName(String name); //Checks if there are any records by name
    Boolean existsBy(); // Checks if there are any records whatsoever

}

LocalDate to java.util.Date and vice versa simplest conversion?

Date to LocalDate

Date date = new Date();
LocalDate localDate = date.toInstant().atZone(ZoneId.systemDefault()).toLocalDate();

LocalDate to Date

LocalDate localDate = LocalDate.now();
Date date = Date.from(localDate.atStartOfDay(ZoneId.systemDefault()).toInstant());

WSDL vs REST Pros and Cons

for enterprise systems in which your system is confined within your corporations, its easier and proper to use soap because you are almost in control of clients. it's easier since there a variety of tools which creates classes (proxies) and looks like you are doing your regular OOP which matches your java or .net environment (in which most corporates use).

I would use REST for internet facing applications for exposing interfaces (like twitter api) since clients can be using javascripts or html or others in which typing is not strict. REST being more liberal makes more sense.

Also for internet facing clients (world wide web), its easier to parse json or xml coming out of a rest interface rather than a purely xml coming from a soap interface. it's hard to use proxies on javascript and javascript does not naturally support objects. If you are using REST with javascript, you would just usually parse the json string and you're off. internet facing interfaces are usually very simple (so most of the time its simple parsing) and does not usually demand consistency that is why REST is adequate enough.

For enterprise applications I don't think REST is adequate because transactions, security, strict typing, schemas play a very important in enterprise applications development that is why SOAP is more suited for them.

My conclusion is that SOAP is for Enterprise systems, REST is for the Internet or WWW. You can use it interchangeably but you may find yourself having a difficult time eventually not using the correct tool for the job.

sorry for my bad english.

Split string with PowerShell and do something with each token

Another way to accomplish this is a combination of Justus Thane's and mklement0's answers. It doesn't make sense to do it this way when you look at a one liner example, but when you're trying to mass-edit a file or a bunch of filenames it comes in pretty handy:

$test = '   One      for the money   '
$option = [System.StringSplitOptions]::RemoveEmptyEntries
$($test.split(' ',$option)).foreach{$_}

This will come out as:

One
for
the
money

Bootstrap 4 card-deck with number of columns based on viewport

This answer is for those who are using Bootstrap 4.1+ and for those who care about IE 11 as well

Card-deck does not adapt the number visible of cards according to the viewport size.

Above methods work but do not support IE. With the below method, you can achieve similar functionality and responsive cards.

You can manage the number of cards to show/hide in different breakpoints.

In Bootstrap 4.1+ columns are same height by default, just make sure your card/content uses all available space. Run the snippet, you'll understand

_x000D_
_x000D_
<link rel="stylesheet" href="https://stackpath.bootstrapcdn.com/bootstrap/4.3.1/css/bootstrap.min.css">_x000D_
<script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.3.1/jquery.min.js"></script>_x000D_
_x000D_
<div class="container">_x000D_
    <div class="row">_x000D_
        <div class="col-sm-6 col-lg-4 mb-3">_x000D_
            <div class="card mb-3 h-100">_x000D_
_x000D_
                <div class="card-body">_x000D_
                    <h5 class="card-title">Card title</h5>_x000D_
                    <p class="card-text">This is a wider card with supporting text below as a natural lead-in to additional content. This content is a little bit longer.</p>_x000D_
                    <p class="card-text"><small class="text-muted">Last updated 3 mins ago</small></p>_x000D_
                </div>_x000D_
            </div>_x000D_
        </div>_x000D_
        <div class="col-sm-6 col-lg-4 mb-3">_x000D_
            <div class="card mb-3 h-100">_x000D_
                <div class="card-body">_x000D_
                    <h5 class="card-title">Card title</h5>_x000D_
                    <p class="card-text">This is a wider card with supporting text below as a natural lead-in to additional content. This content is a little bit longer.</p>_x000D_
                    <p class="card-text"><small class="text-muted">Last updated 3 mins ago</small></p>_x000D_
                </div>_x000D_
            </div>_x000D_
        </div>_x000D_
        <div class="col-sm-6 col-lg-4 mb-3">_x000D_
            <div class="card mb-3 h-100">_x000D_
                <div class="card-body">_x000D_
                    <h5 class="card-title">Card title</h5>_x000D_
                    <p class="card-text">This is a wider card with supporting text below as a natural lead-in to additional content. This content is a little bit longer.</p>_x000D_
                    <p class="card-text"><small class="text-muted">Last updated 3 mins ago</small></p>_x000D_
                </div>_x000D_
            </div>_x000D_
        </div>_x000D_
    </div>_x000D_
</div>
_x000D_
_x000D_
_x000D_

Depend on a branch or tag using a git URL in a package.json?

If it helps anyone, I tried everything above (https w/token mode) - and still nothing was working. I got no errors, but nothing would be installed in node_modules or package_lock.json. If I changed the token or any letter in the repo name or user name, etc. - I'd get an error. So I knew I had the right token and repo name.

I finally realized it's because the name of the dependency I had in my package.json didn't match the name in the package.json of the repo I was trying to pull. Even npm install --verbose doesn't say there's any problem. It just seems to ignore the dependency w/o error.

Error: Cannot Start Container: stat /bin/sh: no such file or directory"

I hit this error ("stat /bin/bash: no such file or directory") when running the command:

docker exec -it 80372bc2c41e /bin/bash

The solution was to identify the kind of terminal (or shell) that is available on the container. To do so, I ran:

docker inspect 80372bc2c41e

In the output from that command, I saw:

"Cmd": [
    "/bin/sh",
    "-c",
    "gunicorn -b 0.0.0.0:7082 server.app:app"
],

This tells me that there's a /bin/sh command available, and I was able to connect with:

docker exec -it 80372bc2c41e /bin/sh

Add animated Gif image in Iphone UIImageView

With Swift and KingFisher

   lazy var animatedPart: AnimatedImageView = {
        let img = AnimatedImageView()
        if let src = Bundle.main.url(forResource: "xx", withExtension: "gif"){
            img.kf.setImage(with: src)
        }
        return img
   }()

Redirecting to URL in Flask

From the Flask API Documentation (v. 0.10):

flask.redirect(location, code=302, Response=None)

Returns a response object (a WSGI application) that, if called, redirects the client to the target location. Supported codes are 301, 302, 303, 305, and 307. 300 is not supported because it’s not a real redirect and 304 because it’s the answer for a request with a request with defined If-Modified-Since headers.

New in version 0.6: The location can now be a unicode string that is encoded using the iri_to_uri() function.

Parameters:

  • location – the location the response should redirect to.
  • code – the redirect status code. defaults to 302.
  • Response (class) – a Response class to use when instantiating a response. The default is werkzeug.wrappers.Response if unspecified.

Delete empty rows

I believe that your problem is that you're checking for an empty string using double quotes instead of single quotes. Try just changing to:

DELETE FROM table WHERE edit_user=''

Add/remove HTML inside div using JavaScript

make a class for that button lets say :

`<input type="button" value="+" class="b1" onclick="addRow()">`

your js should look like this :

$(document).ready(function(){
  $('.b1').click(function(){
      $('div').append('<input type="text"..etc ');
  });
});

converting CSV/XLS to JSON?

This worked perfectly for me and does NOT require a file upload:

https://github.com/cparker15/csv-to-json?files=1

SQL How to correctly set a date variable value and use it?

Your syntax is fine, it will return rows where LastAdDate lies within the last 6 months;

select cast('01-jan-1970' as datetime) as LastAdDate into #PubAdvTransData 
    union select GETDATE()
    union select NULL
    union select '01-feb-2010'

DECLARE @sp_Date DATETIME = DateAdd(m, -6, GETDATE())

SELECT * FROM #PubAdvTransData pat
     WHERE (pat.LastAdDate > @sp_Date)

>2010-02-01 00:00:00.000
>2010-04-29 21:12:29.920

Are you sure LastAdDate is of type DATETIME?

Google server putty connect 'Disconnected: No supported authentication methods available (server sent: publickey)

This problem mainly caused by your connected username not have the access to the shell in GCE. So you use the following steps to solve this issue.

gcloud auth list

If you are using the correct login. please follow the below steps. otherwise use

gcloud auth revoke --all
gcloud auth login [your-iam-user]

and you get the token or it automatically detect the token.

gcloud compute --project "{projectid}" ssh --zone "{zone_name}" "{instance_name}" .

if you dont know this above line click to compute engine-> ssh dropdown arrow-> view google command-> copy that code and use it

Now it update your metadata and it is available in your computer's folder Users->username

~/.ssh/google_compute_engine.ppk
~/.ssh/google_compute_engine.pub

Then you create a new ppk file using puttygen and you give the username, which you want like my_work_space. Then save the publickey and privatekey in a folder.

Next step: Copy the public key data from puttygen and create new ssh key in gcloud metadata

cloud console ->compute engine->metadata->ssh key->add new item->paste the key and save it

and now return your shell commandline tool then enter

sudo chown -R my_work_space /home/my_work_space

now you connect this private key using sftp to anywhere. and it opens the files without showing the permission errors

:) happy hours.

How to pass data from 2nd activity to 1st activity when pressed back? - android

and I Have an issue which I wanted to do this sending data type in a Soft Button which I'd made and the softKey which is the default in every Android Device, so I've done this, first I've made an Intent in my "A" Activity:

            Intent intent = new Intent();
            intent.setClass(context, _AddNewEmployee.class);
            intent.setFlags(Intent.FLAG_ACTIVITY_REORDER_TO_FRONT);
            startActivityForResult(intent, 6969);
            setResult(60);

Then in my second Activity, I've declared a Field in my "B" Activity:

private static int resultCode = 40;

then after I made my request successfully or whenever I wanted to tell the "A" Activity that this job is successfully done here change the value of resultCode to the same I've said in "A" Activity which in my case is "60" and then:

private void backToSearchActivityAndRequest() {
    Intent data = new Intent();
    data.putExtra("PhoneNumber", employeePhoneNumber);
    setResult(resultCode, data);
    finish();
}

@Override
public void onBackPressed() {
    backToSearchActivityAndRequest();
}

PS: Remember to remove the Super from the onBackPressed Method if you want this to work properly.

then I should call the onActivityResult Method in my "A" Activity as well:

   @Override
    protected void onActivityResult(int requestCode, int resultCode, Intent data) {
        super.onActivityResult(requestCode, resultCode, data);
        if (requestCode == 6969 && resultCode == 60) {
            if (data != null) {
                    user_mobile = data.getStringExtra("PhoneNumber");
                    numberTextField.setText(user_mobile);
                    getEmployeeByNumber();
            }
        }
    }

that's it, hope it helps you out. #HappyCoding;