Can't import javax.servlet.annotation.WebServlet
I tried to import the servlet-api.jar to eclipse but still the same also tried to build and clean the project. I don't use tomcat on my eclipse only have it on my net-beans. How can I solve the problem.
Do not put the servlet-api.jar
in your project. This is only asking for trouble. You need to check in the Project Facets section of your project's properties if the Dynamic Web Module facet is set to version 3.0. You also need to ensure that your /WEB-INF/web.xml
(if any) is been declared conform Servlet 3.0 spec. I.e. the <web-app>
root declaration must match the following:
<web-app
xmlns="http://java.sun.com/xml/ns/javaee"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_3_0.xsd"
version="3.0">
In order to be able to import javax.servlet
stuff, you need to integrate a fullworthy servletcontainer like Tomcat in Eclipse and then reference it in Targeted Runtimes of the project's properties. You can do the same for Google App Engine.
Once again, do not copy container-specific libraries into webapp project as others suggest. It would make your webapp unexecutabele on production containers of a different make/version. You'll get classpath-related errors/exceptions in all colors.
See also:
Unrelated to the concrete question: GAE does not support Servlet 3.0. Its underlying Jetty 7.x container supports max Servlet 2.5 only.
Attach the Source in Eclipse of a jar
Go back in to where you added the jar. I believe its the libraries tab, I don't have Eclipse open but that sounds right. to the left of the jar file you added there should be an arrow pointing right, click that and 3 or 4 options expand, one of them being the source file of the library. Click on that and click edit(I think you can also double click it) then locate the file or folder on your hard disk, you probably have to click apply or okay and you're good to go, same with javadoc and i think the last one is native libraries. I don't pay much attention when I'm in there anymore if you couldn't tell. That's what you were asking, right?
How to clear cache of Eclipse Indigo
You can always create a new Eclipse workspace. The Eclipse.exe -clean
option is not sufficient in some cases, for example, if the local history becomes a problem.
Edit:
Eclipse is mostly a collection of third party plugins. And each of those plugins can add some extra useful, useless or problematic information to the central Eclipse workspace meta-data folder.
The problem is that not every plugin participates during the user-issued cleanup routine. Therefore, I'd say that it is a problem in the system design of Eclipse, that it allows plugins to misbehave like this.
And therefore, I'd recommend to make yourself comfortable with the idea of using multiple workspaces and linking-in external project entities into each workspace. Because, this is the only workaround for the given system design, to handle faulty plugins that spam your workspace.
How can I get Eclipse to show .* files?
In your package explorer, pull down the menu and select "Filters ...". You can adjust what types of files are shown/hidden there.
Looking at my Red Hat Developer Studio (approximately Eclipse 3.2), I see that the top item in the list is ".* resources" and it is excluded by default.
JavaScript editor within Eclipse
Eclipse HTML Editor Plugin
I too have struggled with this totally obvious question. It seemed crazy that this wasn't an extremely easy-to-find feature with all the web development happening in Eclipse these days.
I was very turned off by Aptana because of how bloated it is, and the fact that it starts up a local web server (by default on port 8000) everytime you start Eclipse and you can't disable this functionality. Adobe's port of JSEclipse is now a 400Mb plugin, which is equally insane.
However, I just found a super-lightweight JavaScript editor called Eclipse HTML Editor Plugin, made by Amateras, which was exactly what I was looking for.
Eclipse: Syntax Error, parameterized types are only if source level is 1.5
Yes. Regardless of what anyone else says, Eclipse contains some bug(s) that sometimes causes the workspace setting (e.g. 1.6 compliant) to be ignored. This is even when the per-project settings are disabled, the workspace settings are correct (1.6), the JRE is correctly set, there is only a 1.6 JRE defined, etc., all the things that people generally recommend when questions about this issue are posted to various forums (as they often are).
We hit this irregularly, but often, and typically when there is some unrelated issue with build-time dependencies or other project issues. It seems to fall into the general category of "unable to get Eclipse to recognize reality" issues that I always attribute, rightly or wrongly, to refresh issues with Eclipse' extensive metadata. Eclipse metadata is a blessing and a curse; when all is working well, it makes the tool exceedingly powerful and fast. But when there are problems, the extensive caching makes straightening out the issues more difficult - sometimes much more difficult - than with other tools.
Invoking Java main method with parameters from Eclipse
Another idea:
Place all your parameters in a properties file (one parameter = one property in this file), then in your main method, load this file (using Properties.load(*fileInputStream*)
).
So if you want to modify one argument, you will just need to edit your args.properties file, and launch your application without more steps to do...
Of course, this is only for development purposes, but can be really helpfull if you have to change your arguments often...
Eclipse does not highlight matching variables
For others running into this without any of the above solutions working AND you have modified the default theme, you might want to check the highlight color for occurrences.
Preferences > General > Editors > Text Editors > Annotations
Then select Occurrences in the Annotation Types, and change the Color Box to something other than your background color in your editor. You can also change the Highlight to a outline box by Checking "Text as" and selecting "Box" from the drop-down box (which is easier to see various syntax colors then with the highlights)
Developing for Android in Eclipse: R.java not regenerating
One reason the R.class can go missing suddenly is when there are errors in you XML files. For instance, when you add an XML file with uppercase letters in the name like myCoolLayout.xml which is not allowed. Or when you have references that don't point to existing files, etc.
NoClassDefFoundError - Eclipse and Android
This happens quite very often to me.
Last time that happened I can remembered was caused by switching the Eclipse ADT (Google special edition) to Android Studio, and switching back. I basically tried all methods that I can found on stackoverflow which didn't work for me.
Eventually, I got the app working again (no more NoCalssDeffoundError) by switching my IDE to original Eclipse (Kepler) with ADT.
Eclipse Generate Javadoc Wizard: what is "Javadoc Command"?
There are already useful answers to this question above, however there is one more possibility which I don't see being addressed here.
We should consider that the java is installed correctly (that's why eclipse could have been launched in the first place), and the JDK is also added correctly to the eclipse. So the issue might be for some reason (e.g. migration of eclipse to another OS) the path for javadoc is not right which you can easily check and modify in the javadoc wizard page. Here is detailed instructions:
- Open the javadoc wizard by
Project->Generate Javadoc...
- In the javadoc wizard window make sure the
javadoc command
path is correct as illustrated in below screenshot:
The program can't start because cygwin1.dll is missing... in Eclipse CDT
You can compile with either Cygwin's g++
or MinGW (via stand-alone or using Cygwin package). However, in order to run it, you need to add the Cygwin1.dll
(and others) PATH to the system Windows PATH, before any cygwin style paths.
Thus add: ;C:\cygwin64\bin
to the end of your Windows system PATH
variable.
Also, to compile for use in CMD or PowerShell, you may need to use:
x86_64-w64-mingw32-g++.exe -static -std=c++11 prog_name.cc -o prog_name.exe
(This invokes the cross-compiler, if installed.)
Where to put a textfile I want to use in eclipse?
MJB
Please try this
In eclipse "Right click" on the text file u wanna use,
see and copy the complete path stored in HDD like (if in UNIX "/home/sjaisawal/Space-11.4-template/provisioning/devenv/Test/src/testpath/testfile.txt")
put this complete path and try.
if it works then class-path issue else GOK :)
How do I enable TODO/FIXME/XXX task tags in Eclipse?
All those settings are necessary to choose which tags you are interested in, but in order to display these tags in a list, you also need to select the right Eclipse perspective. I finally discovered that the "Markers" tab containing the "Task" list is only available under the "Java EE" perspective... Hope this helps! :-)
Is there an easy way to attach source in Eclipse?
1) Hold Control+ left click on the method you want to see. Then Eclipse will bring you to the Source Not Found page.
2) Click on "Attach Source"
3)
4) Navigate to C:\Program Files\Java\jdk-9.0.1\lib\src.zip
5) Click OK
Now you should see the source code.
How do I configure the proxy settings so that Eclipse can download new plugins?
Just to add to the thread as a POSSIBLE solution, I faced a similar issue when developing on a Linux system that was behind a company firewall. However, using a Windows XP machine, Eclipse was able to access different update sites just fine as both the manual and native network connection providers worked just fine using the company proxy.
After stumbling around for some time, I came across a discussion about using NTLMv2 and an implementation to be found at http://cntlm.sourceforge.net/. To whomever posted this, I give much credit to as it helped me get past the issue running on Linux. As a side note, I was using Eclipse 3.6.2 / Helios on both the Linux and Windows distros.
Best of luck on finding a solution!
Remote debugging Tomcat with Eclipse
Many of the above answers are correct, but remember that by default the debugger will listen on localhost, which means you can debug only if you're running the debugging client (for example, the IDE) on the same machine.
If you are debugging a remote server you will need to specify the correct IP address on that server to listen on, for example
JPDA_OPTS="-agentlib:jdwp=transport=dt_socket,address=10.1.1.33:8000,server=y,suspend=n"
catalina.sh jpda start
Note that the address is now 10.1.1.33:8000
Of course, you can also check which IP is actually being used, by running
netstat -an
This command is valid on both windows and Linux - you just need to filter out the port with find
(Windows) or grep
(Linux).
Where is the Keytool application?
keytool
is part of the standard java distribution.
In a windows 64-bit machine, you would normally find the jdk at
C:\Program Files\Java\jdk1.8.0_121\bin
It is used for managing keys and certificates you can sign things with, in your case, probably a jar file.
If you provide more details of what you need to do, we could probably give you a more specific answer.
Cannot make Project Lombok work on Eclipse
This is for setup of lombok on Spring Tool Suite. Here is what I did on spring tool suite (sts-4.4.0.RELEASE) and lombok-1.18.10.jar (current latest version available in mavenrepository).
If having maven project, ensure lombok dependency added to it. Else you need manually add the jar to your project classpath.
<!-- https://mvnrepository.com/artifact/org.projectlombok/lombok -->
<dependency>
<groupId>org.projectlombok</groupId>
<artifactId>lombok</artifactId>
<version>1.18.10</version>
<scope>provided</scope>
</dependency>
Clean build the maven application. This will download lombok jar in your .m2 location by default from maven repository.
The path would be org\projectlombok\lombok\1.18.10\
Now open command prompt and navigate to the lombok path and execute command java -jar lombok-1.18.10.jar
C:\xxx\xxx\org\projectlombok\lombok\1.18.10>java -jar lombok-1.18.10.jar
Opens up lombok dialog box. If see message Can't find IDE
Click Specify location...
Provide the path to your STS root location
My case it is
C:\apps\sts-4.4.0.RELEASE\SpringToolSuite.exe
Install/Update
Install successful
Click Quit Installer
Now in explorer navigate to your STS root path.
C:\apps\sts-4.4.0.RELEASE\
We see lombok.jar
placed in the sts root path
Now edit in notepad SpringToolSuite4.ini
file
We see following appended at the end
-javaagent:C:\apps\sts-4.4.0.RELEASE\lombok.jar
Start STS using SpringToolSuite4.exe
Clean, rebuild your project.
Eclipse CDT: Symbol 'cout' could not be resolved
Most likely you have some system-specific include directories missing in your settings which makes it impossible for indexer to correctly parse iostream, thus the errors. Selecting Index -> Search For Unresolved Includes
in the context menu of the project will give you the list of unresolved includes which you can search in /usr/include
and add containing directories to C++ Include Paths and Symbols
in Project Properties.
On my system I had to add /usr/include/c++/4.6/x86_64-linux-gnu
for bits/c++config.h
to be resolved and a few more directories.
Don't forget to rebuild the index (Index -> Rebuild) after adding include directories.
Eclipse: Error ".. overlaps the location of another project.." when trying to create new project
I know this is older, but wanted to contribute another possibly solution.
If you want to keep the project location, as I did, I found that copying the .project file from another project into the project's directory, then editing the .project file to name it properly, then choosing the Import Existing Projects into Workspace option worked for me.
In Windows, I used a file monitor to see what Eclipse was doing, and it was simply erroring out for some unknown reason when trying to create the .project file. So, I did that manually and it worked for me.
Subclipse svn:ignore
You can't svn:ignore a file that is already commited to repository.
So you must:
- Delete the file from the repository.
- Update your project (the working copy) to the head revision.
- Recreate the file in Eclipse.
- Set svn:ignore on the file via Team->Add to svn:ignore.
- Restart eclipse to reflect changes.
Good luck!
The type java.util.Map$Entry cannot be resolved. It is indirectly referenced from required .class files
I've seen occasional problems with Eclipse forgetting that built-in classes (including Object
and String
) exist. The way I've resolved them is to:
- On the Project menu, turn off "Build Automatically"
- Quit and restart Eclipse
- On the Project menu, choose "Clean…" and clean all projects
- Turn "Build Automatically" back on and let it rebuild everything.
This seems to make Eclipse forget whatever incorrect cached information it had about the available classes.
Eclipse doesn't stop at breakpoints
Since Eclipse 4.7/Oxygen released in June 2017, there is a new concept of "Triggers for breakpoints", which is displayed as a small "T" next to the breakpoint "blue bullet" icon.
All the other breakpoints that are initially suppressed by triggers
will be hit only after any of the trigger points has been hit. All the
triggers are disabled after a trigger point is hit and will be
re-enabled after the run.
In order to reset all the "trigger" flags, you need to do the following steps :
- Switch to Debug perspective.
- Right-click in the "Breakpoints" view
- Select "Remove All Triggers".
Note : this step does not delete all your breakpoints, which occurs when selecting "Remove All" in the same contextual menu.
Note : the keyboard shortcut to enable the triggers is "Alt-R", which takes precedence on the shortcut to open the "Run" menu with its mnemonics, when the "Breakpoints" view is selected.
Java parsing XML document gives "Content not allowed in prolog." error
The document looks fine to me but I suspect that it contains invisible characters. Open it in a hex editor to check that there really isn't anything before the very first "<". Make sure the spaces in the XML header are spaces. Maybe delete the space before "?>". Check which line breaks are used.
Make sure the document is proper UTF-8. Some windows editors save the document as UTF-16 (i.e. every second byte is 0).
What is log4j's default log file dumping path
To redirect your logs output to a file, you need to use the FileAppender and need to define other file details in your log4j.properties/xml file. Here is a sample properties file for the same:
# Root logger option
log4j.rootLogger=INFO, file
# Direct log messages to a log file
log4j.appender.file=org.apache.log4j.RollingFileAppender
log4j.appender.file.File=C:\\loging.log
log4j.appender.file.MaxFileSize=1MB
log4j.appender.file.MaxBackupIndex=1
log4j.appender.file.layout=org.apache.log4j.PatternLayout
log4j.appender.file.layout.ConversionPattern=%d{yyyy-MM-dd HH:mm:ss} %-5p %c{1}:%L - %m%n
Follow this tutorial to learn more about log4j usage:
http://www.mkyong.com/logging/log4j-log4j-properties-examples/
How to force Eclipse to ask for default workspace?
I can confirm that I am having the same issue. I am also using eclipse classic with CDT. The funny thing is that it only started happening earlier this evening. Before then, I was always prompted for the workspace. Checking "Prompt for workspace on startup" has no effect. I am not launching eclipse using a startup script, so the -data flag is not set on launch. I have removed the line "osgi.instance.area.default" from the configuration/config.ini, but that had no effect.
A few strange quirks that are incidental to this problem: If I delete the "workspace" workspace it creates it again upon launch. However, when I switch to one of my "real" workspaces I notice that the "workspace" workspace is not listed as an option to be switched to.
As would be expected, reinstalling eclipse resolves the issue. But it would be nicer to find a way to fix the problem without resorting to that.
How to unescape HTML character entities in Java?
The most reliable way is with
String cleanedString = StringEscapeUtils.unescapeHtml4(originalString);
from org.apache.commons.lang3.StringEscapeUtils
.
And to escape the whitespaces
cleanedString = cleanedString.trim();
This will ensure that whitespaces due to copy and paste in web forms to not get persisted in DB.
how to run the command mvn eclipse:eclipse
Right click on the project
->Run As
--> Run configurations
.
Then select Maven Build
Then click new button to create a configuration of the selected type. Click on Browse workspace
(now is Workspace...
) then select your project and in goals specify eclipse:eclipse
Eclipse add Tomcat 7 blank server name
In Eclipse Neon.3 Release (4.6.3) on Ubuntu 17.04 with Tomcat 8.0 the problem persists. What helped me was the combination of deleting the prefs files:
rm ~/workspace/.metadata/.plugins/org.eclipse.core.runtime/.settings/org.eclipse.jst.server.tomcat.core.prefs
rm ~/workspace/.metadata/.plugins/org.eclipse.core.runtime/.settings/org.eclipse.wst.server.core.prefs
and linking to catalina.policy
(somewhat differently than how @michael-brooks suggested for his configuration):
sudo ln -s /var/lib/tomcat8/policy/catalina.policy conf/catalina.policy
strange error in my Animation Drawable
Looks like whatever is in your Animation Drawable definition is too much memory to decode and sequence. The idea is that it loads up all the items and make them in an array and swaps them in and out of the scene according to the timing specified for each frame.
If this all can't fit into memory, it's probably better to either do this on your own with some sort of handler or better yet just encode a movie with the specified frames at the corresponding images and play the animation through a video codec.
Any way to generate ant build.xml file automatically from Eclipse?
If all you need is the classpath entries, I do something like the following to use the eclipse build path.
<xmlproperty file=".classpath" collapseAttributes="true" delimiter=";" />
Then set that value in the path
<path id="eclipse.classpath">
<pathelement path="${classpath.classpathentry.path}"/>
</path>
<target name="compile" depends="init">
<javac srcdir="${src}" destdir="${build}" updatedProperty="compiled">
<classpath refid="eclipse.classpath"/>
</javac>
</target>
How to connect to a remote MySQL database with Java?
On Ubuntu, after creating localhost and '%' versions of the user, and granting appropriate access to database.tables for both, I had to comment out the 'bind-address' in /etc/mysql/mysql.conf.d/mysql.cnf and restart mysql as sudo.
bind-address = 127.0.0.1
Eclipse - debugger doesn't stop at breakpoint
In order to debugger work with remote, the java .class files must be complied along with debugging information. If "-g:none" option was passed to compiler then the class file will not have necessary information and hence debugger will not be able to match breakpoints on source code with that class in remote. Meanwhile, if jars/class files were obfuscated, then they also will not have any debug info. According to your responses, most probably this is not your case, but this info could be useful for others who face the same issue.
Eclipse - "Workspace in use or cannot be created, chose a different one."
I've seen 3 other fixes so far:
- in .metadata/, rm .lock file
- if 1) doesn't work, try end process javaw.exe etc. to exit the IDE
- if 1)&2) doesn't work, try rm .log file in .metadata/, and double check .plugin/.
- This always worked for me: relocate .metadata/, open and close eclipse, then overwrite .metadata back
The solution boils down to clean up the .metadata folder with correct contents
import android packages cannot be resolved
This import android packages cannot be resolved
is also occurs when your using some library and that library is not in the same path where your application is there, or if you are importing the library and not coping library to the workspace
Maven Java EE Configuration Marker with Java Server Faces 1.2
After changing lots in my POM and updating my JDK I was getting the "One or more constraints have not been satisfied" related to Google App Engine. The solution was to delete the Eclipse project settings and reimport it.
On OS X, I did this in Terminal by changing to the project directory and
rm -rf .project
rm -rf .settings
Maven in Eclipse: step by step installation
I was having problems because I was looking to install the Maven plugin on MuleStudio not Eclipse..
[for MuleStudio 1.2 or below do steps (1) and (2) otherwise jump to step (2)]
Instructions for MuleStudio (ONLY versions 1.2 and below):
(1) Help >install new software...
Helios Update Site - http://download.eclipse.org/releases/helios/
Instructions for MuleStudio (1.3) OR Eclipse:
(2) Help >install new software...
Maven - URL: http://download.eclipse.org/technology/m2e/releases
Eclipse/Java code completion not working
Try restoring the default options in 'Windows > Preferences > Java > Editor > Content Assist > Advanced
'
An example of the kind of data you see in this preference screen, however not necessarily what you currently have.
(From Vadim in this blog post " Content Assist Duplicates in Eclipse (Mylyn)":
if have duplicate Mylyn entries, uncheck the duplicate entries that do not contain "(Mylyn)
" in their name)
The Eclipse help page defines the default list to restore:
Select the proposal kinds contained in the 'default' content assist list:
- Other Java Proposals,
- SWT Template Proposals,
- Template Proposals,
- Type Proposals
How to solve maven 2.6 resource plugin dependency?
This issue is happening due to change of protocol from http to https for central repository. please refer following link for more details. https://support.sonatype.com/hc/en-us/articles/360041287334-Central-501-HTTPS-Required
In order to fix the problem, copy following into your pom.ml file. This will set the repository url to use https.
<repositories>
<repository>
<snapshots>
<enabled>false</enabled>
</snapshots>
<id>central</id>
<name>Central Repository</name>
<url>https://repo.maven.apache.org/maven2</url>
</repository>
</repositories>
<pluginRepositories>
<pluginRepository>
<releases>
<updatePolicy>never</updatePolicy>
</releases>
<snapshots>
<enabled>false</enabled>
</snapshots>
<id>central</id>
<name>Central Repository</name>
<url>https://repo.maven.apache.org/maven2</url>
</pluginRepository>
</pluginRepositories>
Eclipse Bug: Unhandled event loop exception No more handles
"unhandled event loop exception .. no more handles" error (in my case) was caused by the driver of my mouse ! closing my mouse driver solved the problem. It has nothing to do with Eclipse versions, I tried almost all versions after Helios(in both 64bit/32bit) and all of them have the same problem, I also tried to add Eclipse/JRE variable path within advanced windows settings "environment variables". To help you to resolve this error try to close up unused applications and drivers.
Maven error "Failure to transfer..."
Give correct maven setting.xml path in eclipse.
- Windows --> Preference --> Maven --> User Settings
Enter correct setting.xml path in user settings text box
Eclipse java debugging: source not found
The symptoms perfectly describes the case when the found class doesn't have associated (or assigned) source.
- You can associate the sources for JDK classes in Preferences > Java > Installed JRE. If JRE (not JDK) is detected as default JRE to be used, then your JDK classes won't have attached sources. Note that, not all of the JDK classes have provided sources, some of them are distributed in binary form only.
- Classes from project's build path, added manually requires that you manually attach the associated source. The source can reside in a zip or jar file, in the workspace or in the filesystem. Eclipse will scan the zip, so your sources doesn't have to be in the root of the archive file, for example.
- Classes, from dependencies coming from another plugins (maven, PDE, etc.). In this case, it is up to the plugin how the source will be provided.
- PDE will require that each plugin have corresponding XXX.source bundle, which contains the source of the plugin. More information can be found here and here.
- m2eclipse can fetch sources and javadocs for Maven dependencies if they are available. This feature should be enabled m2eclipse preferences (the option was named something like "Download source and javadocs".
- For other plugins, you'll need to consult their documentation
- Classes, which are loaded from your project are automatically matched with the sources from the project.
But what if Eclipse still suggest that you attach source, even if I correctly set my classes and their sources:
This almost always means that Eclipse is finding the class from different place than you expect. Inspect your source lookup path to see where it might get the wrong class. Update the path accordingly to your findings.
Eclipse doesn't find anything at all, when breakpoint is hit:
This happens, when you are source lookup path doesn't contain the class, which is currently loaded in the runtime. Even if the class is in the workspace, it can be invisible to the launch configuration, because Eclipse follows the source lookup path strictly and attaches only the dependencies of the project, which is currently debugged.
An exception is the debugging bundles in PDE. In this case, because the runtime is composed from multiple projects, which doesn't have to declare dependencies on one another, Eclipse will automatically find the class in the workspace, even if it is not available in the source lookup path.
I cannot see the variables when I hit a breakpoint or it just opens the source, but doesn't select the breakpoint line:
This means that in the runtime, either the JVM or the classes themselves doesn't have the necessary debug information. Each time classes are compiled, debug information can be attached. To reduce the storage space of the classes, sometimes this information is omitted, which makes debugging such code a pain. Your only chance is to try and recompile with debug enabled.
Eclipse source viewer shows different lines than those that are actually executed:
It sometimes can show that empty space is executed as well. This means that your sources doesn't match your runtime version of the classes. Even if you think that this is not possible, it is, so make sure you setup the correct sources. Or your runtime match your latest changes, depending on what are you trying to do.
Where in an Eclipse workspace is the list of projects stored?
Windows:
<workspace>\.metadata\.plugins\org.eclipse.core.resources\.projects\
Linux / osx:
<workspace>/.metadata/.plugins/org.eclipse.core.resources/.projects/
Your project can exist outside the workspace, but all Eclipse-specific metadata
are stored in that org.eclipse.core.resources\.projects
directory
Eclipse: How to install a plugin manually?
- Download your plugin
- Open Eclipse
- From the menu choose:
Help
/ Install New Software...
- Click the
Add
button
- In the
Add Repository
dialog that appears, click the Archive
button next to the Location
field
- Select your plugin file, click
OK
You could also just copy plugins to the eclipse/plugins
directory, but it's not recommended.
Run "mvn clean install" in Eclipse
I use eclipse STS, so the maven plugin comes pre-installed. However, if you aren't using STS (Springsource Tool Suite), you can still install the m2Eclipse plugin. Here is the link:
http://www.eclipse.org/m2e/
Once you have this installed, you should be able to run all the maven commands. To do so, from the package explorer, you would right click on either the maven project or the pom.xml in the maven project, highlight Run As, then click Maven Install.
Hope this helped.
Error in Eclipse: "The project cannot be built until build path errors are resolved"
Open the Problems view. You can open this view by clicking on the small + sign at the left hand bottom corner of eclipse. It's a very tiny plus with a rectangle around it. Click on it and select problems.
The problem view will show you the problems that need to be resolved.
- If the message says "the project is missing the required libraries...", you need to configure your build path by right clicking on your project, selecting properties, then build path. Add the required jar files using the libraries tab.
-If there are other problems other than missing libraries, you need to post the exact problems here to get a precise solution.
How do I go about adding an image into a java project with eclipse?
It is very simple to adding an image into project and view the image.
First create a folder into in your project which can contain any type of images.
Then Right click on Project ->>
Go to Build Path ->>
configure Build Path ->>
add Class folder ->>
choose your folder (which you just created for store the images) under the project name.
class Surface extends JPanel {
private BufferedImage slate;
private BufferedImage java;
private BufferedImage pane;
private TexturePaint slatetp;
private TexturePaint javatp;
private TexturePaint panetp;
public Surface() {
loadImages();
}
private void loadImages() {
try {
slate = ImageIO.read(new File("images\\slate.png"));
java = ImageIO.read(new File("images\\java.png"));
pane = ImageIO.read(new File("images\\pane.png"));
} catch (IOException ex) {
Logger.`enter code here`getLogger(Surface.class.getName()).log(
Level.SEVERE, null, ex);
}
}
private void doDrawing(Graphics g) {
Graphics2D g2d = (Graphics2D) g.create();
slatetp = new TexturePaint(slate, new Rectangle(0, 0, 90, 60));
javatp = new TexturePaint(java, new Rectangle(0, 0, 90, 60));
panetp = new TexturePaint(pane, new Rectangle(0, 0, 90, 60));
g2d.setPaint(slatetp);
g2d.fillRect(10, 15, 90, 60);
g2d.setPaint(javatp);
g2d.fillRect(130, 15, 90, 60);
g2d.setPaint(panetp);
g2d.fillRect(250, 15, 90, 60);
g2d.dispose();
}
@Override
public void paintComponent(Graphics g) {
super.paintComponent(g);
doDrawing(g);
}
}
public class TexturesEx extends JFrame {
public TexturesEx() {
initUI();
}
private void initUI() {
add(new Surface());
setTitle("Textures");
setSize(360, 120);
setLocationRelativeTo(null);
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
}
public static void main(String[] args) {
EventQueue.invokeLater(new Runnable() {
@Override
public void run() {
TexturesEx ex = new TexturesEx();
ex.setVisible(true);
}
});
}
}
Apache Tomcat Not Showing in Eclipse Server Runtime Environments
I had the same problem and I solved it with the following steps
- Help > Install New Software...
- Select "Eclipse Web Tools Platform Repository (http://download.eclipse.org/webtools/updates)" from the "Work with" drop-down.
- Select "Web Tools Platform (WTP)" and "Project Provided Components".
Complete all the installation steps and restart Eclipse. You'll see a bunch of servers when you try to add a server runtime environment.
Java stack overflow error - how to increase the stack size in Eclipse?
i also have the same problem while parsing schema definition files(XSD) using XSOM library,
i was able to increase Stack memory upto 208Mb then it showed heap_out_of_memory_error
for which i was able to increase only upto 320mb.
the final configuration was -Xmx320m -Xss208m
but then again it ran for some time and failed.
My function prints recursively the entire tree of the schema definition,amazingly the output file crossed 820Mb for a definition file of 4 Mb(Aixm library) which in turn uses 50 Mb of schema definition library(ISO gml).
with that I am convinced I have to avoid Recursion and then start iteration and some other way of representing the output, but I am having little trouble converting all that recursion to iteration.
Revert to Eclipse default settings
Not even a single answer of the above let me able to get the original theme as I expected. I tried myself & got my default theme by changing the workspace. This led me to the original theme (same-to-same) that I used to saw when installing eclipse !
Best GUI designer for eclipse?
well check out the eclipse distro easyeclipse at EasyEclipse. it has Visual editor project already added as a plugin, so no hassles of eclipse version compatibility.Plus the eclipse help section has a tutorial on VE.
How do you split and unsplit a window/view in Eclipse IDE?
This is possible with the menu items Window>Editor>Toggle Split Editor.
Current shortcut for splitting is:
Azerty keyboard:
- Ctrl + _ for split horizontally, and
- Ctrl + { for split vertically.
Qwerty US keyboard:
- Ctrl + Shift + - (accessing _) for split horizontally, and
- Ctrl + Shift + [ (accessing {) for split vertically.
MacOS - Qwerty US keyboard:
- ⌘ + Shift + - (accessing _) for split horizontally, and
- ⌘ + Shift + [ (accessing {) for split vertically.
On any other keyboard if a required key is unavailable (like { on a german Qwertz keyboard), the following generic approach may work:
- Alt + ASCII code + Ctrl then release Alt
Example: ASCII for '{' = 123, so press 'Alt', '1', '2', '3', 'Ctrl' and release 'Alt', effectively typing '{' while 'Ctrl' is pressed, to split vertically.
Example of vertical split:
PS:
- The menu items Window>Editor>Toggle Split Editor were added with Eclipse Luna 4.4 M4, as mentioned by Lars Vogel in "Split editor implemented in Eclipse M4 Luna"
- The split editor is one of the oldest and most upvoted Eclipse bug! Bug 8009
- The split editor functionality has been developed in Bug 378298, and will be available as of Eclipse Luna M4. The Note & Newsworthy of Eclipse Luna M4 will contain the announcement.
Eclipse CDT: no rule to make target all
Select Project->Properties from the menu bar.
Click C/C++ Build on the left in the dialog that comes up.
- Under the Builder Settings tab on the right, check and make sure the "Build location" is correct.
Getting selected value of a combobox
I had a similar error, My Class is
public class ServerInfo
{
public string Text { get; set; }
public string Value { get; set; }
public string PortNo { get; set; }
public override string ToString()
{
return Text;
}
}
But what I did, I casted my class to the SelectedItem property of the ComboBox. So, i'll have all of the class properties of the selected item.
// Code above
ServerInfo emailServer = (ServerInfo)cbServerName.SelectedItem;
mailClient.ServerName = emailServer.Value;
mailClient.ServerPort = emailServer.PortNo;
I hope this helps someone!
Cheers!
Convert String to Double - VB
VB.NET Sample Code
Dim A as String = "5.3"
Dim B as Double
B = CDbl(Val(A)) '// Val do hard work
'// Get output
MsgBox (B) '// Output is 5,3 Without Val result is 53.0
Comparing date part only without comparing time in JavaScript
This is the way I do it:
var myDate = new Date($('input[name=frequency_start]').val()).setHours(0,0,0,0);
var today = new Date().setHours(0,0,0,0);
if(today>myDate){
jAlert('Please Enter a date in the future','Date Start Error', function(){
$('input[name=frequency_start]').focus().select();
});
}
Style jQuery autocomplete in a Bootstrap input field
If you're using jQuery-UI, you must include the jQuery UI CSS package, otherwise the UI components don't know how to be styled.
If you don't like the jQuery UI styles, then you'll have to recreate all the styles it would have otherwise applied.
Here's an example and some possible fixes.
Here's a demo in Stack Snippets without jquery-ui.css (doesn't work)
_x000D_
_x000D_
$(function() {_x000D_
var availableTags = [_x000D_
"ActionScript", "AppleScript", "Asp", "BASIC", "C", "C++",_x000D_
"Clojure", "COBOL", "ColdFusion", "Erlang", "Fortran",_x000D_
"Groovy", "Haskell", "Java", "JavaScript", "Lisp", "Perl",_x000D_
"PHP", "Python", "Ruby", "Scala", "Scheme"_x000D_
];_x000D_
_x000D_
$(".autocomplete").autocomplete({_x000D_
source: availableTags_x000D_
});_x000D_
});
_x000D_
<link href="//cdnjs.cloudflare.com/ajax/libs/twitter-bootstrap/3.3.2/css/bootstrap.css" rel="stylesheet"/>_x000D_
_x000D_
<script src="//cdnjs.cloudflare.com/ajax/libs/jquery/2.1.3/jquery.js"></script>_x000D_
<script src="//cdnjs.cloudflare.com/ajax/libs/jqueryui/1.11.2/jquery-ui.js"></script>_x000D_
<script src="//cdnjs.cloudflare.com/ajax/libs/twitter-bootstrap/3.3.2/js/bootstrap.js"></script>_x000D_
_x000D_
<div class="container">_x000D_
_x000D_
<div class="form-group">_x000D_
<label>Languages</label>_x000D_
<input class="form-control autocomplete" placeholder="Enter A" />_x000D_
</div>_x000D_
_x000D_
<div class="form-group">_x000D_
<label >Another Field</label>_x000D_
<input class="form-control">_x000D_
</div>_x000D_
_x000D_
</div>
_x000D_
_x000D_
_x000D_
Fix #1 - jQuery-UI Style
Just include jquery-ui.css and everything should work just fine with the latest supported versions of jquery.
_x000D_
_x000D_
$(function() {_x000D_
var availableTags = [_x000D_
"ActionScript", "AppleScript", "Asp", "BASIC", "C", "C++",_x000D_
"Clojure", "COBOL", "ColdFusion", "Erlang", "Fortran",_x000D_
"Groovy", "Haskell", "Java", "JavaScript", "Lisp", "Perl",_x000D_
"PHP", "Python", "Ruby", "Scala", "Scheme"_x000D_
];_x000D_
_x000D_
$(".autocomplete").autocomplete({_x000D_
source: availableTags_x000D_
});_x000D_
});
_x000D_
<link href="//cdnjs.cloudflare.com/ajax/libs/jqueryui/1.11.2/jquery-ui.css" rel="stylesheet"/>_x000D_
<link href="//cdnjs.cloudflare.com/ajax/libs/twitter-bootstrap/3.3.2/css/bootstrap.css" rel="stylesheet"/>_x000D_
_x000D_
<script src="//cdnjs.cloudflare.com/ajax/libs/jquery/2.1.3/jquery.js"></script>_x000D_
<script src="//cdnjs.cloudflare.com/ajax/libs/jqueryui/1.11.2/jquery-ui.js"></script>_x000D_
<script src="//cdnjs.cloudflare.com/ajax/libs/twitter-bootstrap/3.3.2/js/bootstrap.js"></script>_x000D_
_x000D_
<div class="container">_x000D_
<div class="form-group">_x000D_
<label>Languages</label>_x000D_
<input class="form-control autocomplete" placeholder="Enter A" />_x000D_
</div>_x000D_
_x000D_
<div class="form-group">_x000D_
<label >Another Field</label>_x000D_
<input class="form-control">_x000D_
</div>_x000D_
</div>
_x000D_
_x000D_
_x000D_
Fix #2 - Bootstrap Theme
There is a project that created a Bootstrap-esque theme for jQuery-UI components called jquery-ui-bootstrap. Just grab the stylesheet from there and you should be all set.
_x000D_
_x000D_
$(function() {_x000D_
var availableTags = [_x000D_
"ActionScript", "AppleScript", "Asp", "BASIC", "C", "C++",_x000D_
"Clojure", "COBOL", "ColdFusion", "Erlang", "Fortran",_x000D_
"Groovy", "Haskell", "Java", "JavaScript", "Lisp", "Perl",_x000D_
"PHP", "Python", "Ruby", "Scala", "Scheme"_x000D_
];_x000D_
_x000D_
$(".autocomplete").autocomplete({_x000D_
source: availableTags_x000D_
});_x000D_
});
_x000D_
<link href="https://cdnjs.cloudflare.com/ajax/libs/jquery-ui-bootstrap/0.5pre/css/custom-theme/jquery-ui-1.10.0.custom.css" rel="stylesheet"/>_x000D_
<link href="//cdnjs.cloudflare.com/ajax/libs/twitter-bootstrap/3.3.2/css/bootstrap.css" rel="stylesheet"/>_x000D_
_x000D_
<script src="//cdnjs.cloudflare.com/ajax/libs/jquery/2.1.3/jquery.js"></script>_x000D_
<script src="//cdnjs.cloudflare.com/ajax/libs/jqueryui/1.11.2/jquery-ui.js"></script>_x000D_
<script src="//cdnjs.cloudflare.com/ajax/libs/twitter-bootstrap/3.3.2/js/bootstrap.js"></script>_x000D_
_x000D_
<div class="container">_x000D_
<div class="form-group">_x000D_
<label>Languages</label>_x000D_
<input class="form-control autocomplete" placeholder="Enter A" />_x000D_
</div>_x000D_
_x000D_
<div class="form-group">_x000D_
<label >Another Field</label>_x000D_
<input class="form-control">_x000D_
</div>_x000D_
</div>
_x000D_
_x000D_
_x000D_
Fix #3 - Manual CSS
If you only need the AutoComplete widget from jQuery-UI's library, you should start by doing a custom build so you don't pull in resources you're not using.
After that, you'll need to style it yourself. Just look at some of the other styles that are applied to jquery's autocomplete.css and theme.css to figure out what styles you'll need to manually replace.
You can use bootstrap's dropdowns.less for inspiration.
Here's a sample CSS that fits pretty well with Bootstrap's default theme:
.ui-autocomplete {
position: absolute;
z-index: 1000;
cursor: default;
padding: 0;
margin-top: 2px;
list-style: none;
background-color: #ffffff;
border: 1px solid #ccc;
-webkit-border-radius: 5px;
-moz-border-radius: 5px;
border-radius: 5px;
-webkit-box-shadow: 0 5px 10px rgba(0, 0, 0, 0.2);
-moz-box-shadow: 0 5px 10px rgba(0, 0, 0, 0.2);
box-shadow: 0 5px 10px rgba(0, 0, 0, 0.2);
}
.ui-autocomplete > li {
padding: 3px 20px;
}
.ui-autocomplete > li.ui-state-focus {
background-color: #DDD;
}
.ui-helper-hidden-accessible {
display: none;
}
_x000D_
_x000D_
$(function() {_x000D_
var availableTags = [_x000D_
"ActionScript", "AppleScript", "Asp", "BASIC", "C", "C++",_x000D_
"Clojure", "COBOL", "ColdFusion", "Erlang", "Fortran",_x000D_
"Groovy", "Haskell", "Java", "JavaScript", "Lisp", "Perl",_x000D_
"PHP", "Python", "Ruby", "Scala", "Scheme"_x000D_
];_x000D_
_x000D_
$(".autocomplete").autocomplete({_x000D_
source: availableTags_x000D_
});_x000D_
});
_x000D_
.ui-autocomplete {_x000D_
position: absolute;_x000D_
z-index: 1000;_x000D_
cursor: default;_x000D_
padding: 0;_x000D_
margin-top: 2px;_x000D_
list-style: none;_x000D_
background-color: #ffffff;_x000D_
border: 1px solid #ccc_x000D_
-webkit-border-radius: 5px;_x000D_
-moz-border-radius: 5px;_x000D_
border-radius: 5px;_x000D_
-webkit-box-shadow: 0 5px 10px rgba(0, 0, 0, 0.2);_x000D_
-moz-box-shadow: 0 5px 10px rgba(0, 0, 0, 0.2);_x000D_
box-shadow: 0 5px 10px rgba(0, 0, 0, 0.2);_x000D_
}_x000D_
.ui-autocomplete > li {_x000D_
padding: 3px 20px;_x000D_
}_x000D_
.ui-autocomplete > li.ui-state-focus {_x000D_
background-color: #DDD;_x000D_
}_x000D_
.ui-helper-hidden-accessible {_x000D_
display: none;_x000D_
}
_x000D_
<link href="//cdnjs.cloudflare.com/ajax/libs/twitter-bootstrap/3.3.2/css/bootstrap.css" rel="stylesheet"/>_x000D_
_x000D_
<script src="//cdnjs.cloudflare.com/ajax/libs/jquery/2.1.3/jquery.js"></script>_x000D_
<script src="//cdnjs.cloudflare.com/ajax/libs/jqueryui/1.11.2/jquery-ui.js"></script>_x000D_
<script src="//cdnjs.cloudflare.com/ajax/libs/twitter-bootstrap/3.3.2/js/bootstrap.js"></script>_x000D_
_x000D_
<div class="container">_x000D_
<div class="form-group ui-widget">_x000D_
<label>Languages</label>_x000D_
<input class="form-control autocomplete" placeholder="Enter A" />_x000D_
</div>_x000D_
_x000D_
<div class="form-group ui-widget">_x000D_
<label >Another Field</label>_x000D_
<input class="form-control" />_x000D_
</div>_x000D_
</div>
_x000D_
_x000D_
_x000D_
Tip: Since the dropdown menu hides every time you go to inspect the element (i.e. whenever the input loses focus), for easier debugging of the style, find the control with .ui-autocomplete
and remove display: none;
.
How does autowiring work in Spring?
Depends on whether you want the annotations route or the bean XML definition route.
Say you had the beans defined in your applicationContext.xml
:
<beans ...>
<bean id="userService" class="com.foo.UserServiceImpl"/>
<bean id="fooController" class="com.foo.FooController"/>
</beans>
The autowiring happens when the application starts up. So, in fooController
, which for arguments sake wants to use the UserServiceImpl
class, you'd annotate it as follows:
public class FooController {
// You could also annotate the setUserService method instead of this
@Autowired
private UserService userService;
// rest of class goes here
}
When it sees @Autowired
, Spring will look for a class that matches the property in the applicationContext
, and inject it automatically. If you have more than one UserService
bean, then you'll have to qualify which one it should use.
If you do the following:
UserService service = new UserServiceImpl();
It will not pick up the @Autowired
unless you set it yourself.
Proxy with urllib2
One can also use requests if we would like to access a web page using proxies. Python 3 code:
>>> import requests
>>> url = 'http://www.google.com'
>>> proxy = '169.50.87.252:80'
>>> requests.get(url, proxies={"http":proxy})
<Response [200]>
More than one proxies can also be added.
>>> proxy1 = '169.50.87.252:80'
>>> proxy2 = '89.34.97.132:8080'
>>> requests.get(url, proxies={"http":proxy1,"http":proxy2})
<Response [200]>
Java switch statement multiple cases
It is possible to handle this using Vavr library
import static io.vavr.API.*;
import static io.vavr.Predicates.*;
Match(variable).of(
Case($(isIn(5, 6, ... , 100)), () -> doSomething()),
Case($(), () -> handleCatchAllCase())
);
This is of course only slight improvement since all cases still need to be listed explicitly. But it is easy to define custom predicate:
public static <T extends Comparable<T>> Predicate<T> isInRange(T lower, T upper) {
return x -> x.compareTo(lower) >= 0 && x.compareTo(upper) <= 0;
}
Match(variable).of(
Case($(isInRange(5, 100)), () -> doSomething()),
Case($(), () -> handleCatchAllCase())
);
Match is an expression so here it returns something like Runnable
instance instead of invoking methods directly. After match is performed Runnable
can be executed.
For further details please see official documentation.
fork and exec in bash
Use the ampersand just like you would from the shell.
#!/usr/bin/bash
function_to_fork() {
...
}
function_to_fork &
# ... execution continues in parent process ...
Select all DIV text with single mouse click
For content editable stuff (not regular inputs, you need to use selectNodeContents (rather than just selectNode).
NOTE: All the references to "document.selection" and "createTextRange()" are for IE 8 and lower... You'll not likely need to support that monster if you're attempting to do tricky stuff like this.
function selectElemText(elem) {
//Create a range (a range is a like the selection but invisible)
var range = document.createRange();
// Select the entire contents of the element
range.selectNodeContents(elem);
// Don't select, just positioning caret:
// In front
// range.collapse();
// Behind:
// range.collapse(false);
// Get the selection object
var selection = window.getSelection();
// Remove any current selections
selection.removeAllRanges();
// Make the range you have just created the visible selection
selection.addRange(range);
}
Difference between JOIN and INNER JOIN
As the other answers already state there is no difference in your example.
The relevant bit of grammar is documented here
<join_type> ::=
[ { INNER | { { LEFT | RIGHT | FULL } [ OUTER ] } } [ <join_hint> ] ]
JOIN
Showing that all are optional. The page further clarifies that
INNER
Specifies all matching pairs of rows are returned. Discards
unmatched rows from both tables. When no join type is specified, this
is the default.
The grammar does also indicate that there is one time where the INNER
is required though. When specifying a join hint.
See the example below
CREATE TABLE T1(X INT);
CREATE TABLE T2(Y INT);
SELECT *
FROM T1
LOOP JOIN T2
ON X = Y;
SELECT *
FROM T1
INNER LOOP JOIN T2
ON X = Y;
Style input element to fill remaining width of its container
you can try this :
_x000D_
_x000D_
div#panel {_x000D_
border:solid;_x000D_
width:500px;_x000D_
height:300px;_x000D_
}_x000D_
div#content {_x000D_
height:90%;_x000D_
background-color:#1ea8d1; /*light blue*/_x000D_
}_x000D_
div#panel input {_x000D_
width:100%;_x000D_
height:10%;_x000D_
/*make input doesnt overflow inside div*/_x000D_
-webkit-box-sizing: border-box;_x000D_
-moz-box-sizing: border-box;_x000D_
box-sizing: border-box;_x000D_
/*make input doesnt overflow inside div*/_x000D_
}
_x000D_
<div id="panel">_x000D_
<div id="content"></div>_x000D_
<input type="text" placeholder="write here..."/>_x000D_
</div>
_x000D_
_x000D_
_x000D_
Stacked Tabs in Bootstrap 3
Left, Right and Below tabs were removed from Bootstrap 3, but you can add custom CSS to achieve this..
.tabs-below > .nav-tabs,
.tabs-right > .nav-tabs,
.tabs-left > .nav-tabs {
border-bottom: 0;
}
.tab-content > .tab-pane,
.pill-content > .pill-pane {
display: none;
}
.tab-content > .active,
.pill-content > .active {
display: block;
}
.tabs-below > .nav-tabs {
border-top: 1px solid #ddd;
}
.tabs-below > .nav-tabs > li {
margin-top: -1px;
margin-bottom: 0;
}
.tabs-below > .nav-tabs > li > a {
-webkit-border-radius: 0 0 4px 4px;
-moz-border-radius: 0 0 4px 4px;
border-radius: 0 0 4px 4px;
}
.tabs-below > .nav-tabs > li > a:hover,
.tabs-below > .nav-tabs > li > a:focus {
border-top-color: #ddd;
border-bottom-color: transparent;
}
.tabs-below > .nav-tabs > .active > a,
.tabs-below > .nav-tabs > .active > a:hover,
.tabs-below > .nav-tabs > .active > a:focus {
border-color: transparent #ddd #ddd #ddd;
}
.tabs-left > .nav-tabs > li,
.tabs-right > .nav-tabs > li {
float: none;
}
.tabs-left > .nav-tabs > li > a,
.tabs-right > .nav-tabs > li > a {
min-width: 74px;
margin-right: 0;
margin-bottom: 3px;
}
.tabs-left > .nav-tabs {
float: left;
margin-right: 19px;
border-right: 1px solid #ddd;
}
.tabs-left > .nav-tabs > li > a {
margin-right: -1px;
-webkit-border-radius: 4px 0 0 4px;
-moz-border-radius: 4px 0 0 4px;
border-radius: 4px 0 0 4px;
}
.tabs-left > .nav-tabs > li > a:hover,
.tabs-left > .nav-tabs > li > a:focus {
border-color: #eeeeee #dddddd #eeeeee #eeeeee;
}
.tabs-left > .nav-tabs .active > a,
.tabs-left > .nav-tabs .active > a:hover,
.tabs-left > .nav-tabs .active > a:focus {
border-color: #ddd transparent #ddd #ddd;
*border-right-color: #ffffff;
}
.tabs-right > .nav-tabs {
float: right;
margin-left: 19px;
border-left: 1px solid #ddd;
}
.tabs-right > .nav-tabs > li > a {
margin-left: -1px;
-webkit-border-radius: 0 4px 4px 0;
-moz-border-radius: 0 4px 4px 0;
border-radius: 0 4px 4px 0;
}
.tabs-right > .nav-tabs > li > a:hover,
.tabs-right > .nav-tabs > li > a:focus {
border-color: #eeeeee #eeeeee #eeeeee #dddddd;
}
.tabs-right > .nav-tabs .active > a,
.tabs-right > .nav-tabs .active > a:hover,
.tabs-right > .nav-tabs .active > a:focus {
border-color: #ddd #ddd #ddd transparent;
*border-left-color: #ffffff;
}
Working example: http://bootply.com/74926
UPDATE
If you don't need the exact look of a tab (bordered appropriately on the left or right as each tab is activated), you can simple use nav-stacked
, along with Bootstrap col-*
to float the tabs to the left or right...
nav-stacked
demo: http://codeply.com/go/rv3Cvr0lZ4
<ul class="nav nav-pills nav-stacked col-md-3">
<li><a href="#a" data-toggle="tab">1</a></li>
<li><a href="#b" data-toggle="tab">2</a></li>
<li><a href="#c" data-toggle="tab">3</a></li>
</ul>
Cookies vs. sessions
when you save the #ID as the cookie to recognize logged in users, you actually are showing data to users that is not related to them. In addition, if a third party tries to set random IDs as cookie data in their browser, they will be able to convince the server that they are a user while they actually are not. That's a lack of security.
You have used cookies, and as you said you have already completed most of the project. besides cookie has the privilege of remaining for a long time, while sessions end more quickly. So sessions are not suitable in this case. In reality many famous and popular websites and services use cookie and you can stay logged-in for a long time. But how can you use their method to create a safer log-in process?
here's the idea: you can help the way you use cookies: If you use random keys instead of IDs to recognize logged-in users, first, you don't leak your primary data to random users, and second, If you consider the Random key large enough, It will be harder for anyone to guess a key or create a random one. for example you can save a 40 length key like this in User's browser:
"KUYTYRFU7987gJHFJ543JHBJHCF5645UYTUYJH54657jguthfn"
and it will be less likely for anyone to create the exact key and pretend to be someone else.
How to create a JSON object
You just need another layer in your php array:
$post_data = array(
'item' => array(
'item_type_id' => $item_type,
'string_key' => $string_key,
'string_value' => $string_value,
'string_extra' => $string_extra,
'is_public' => $public,
'is_public_for_contacts' => $public_contacts
)
);
echo json_encode($post_data);
SSH -L connection successful, but localhost port forwarding not working "channel 3: open failed: connect failed: Connection refused"
ssh -v -L 8783:localhost:8783 [email protected]
...
channel 3: open failed: connect failed: Connection refused
When you connect to port 8783 on your local system, that connection is tunneled through your ssh link to the ssh server on server.com. From there, the ssh server makes TCP connection to localhost port 8783 and relays data between the tunneled connection and the connection to target of the tunnel.
The "connection refused" error is coming from the ssh server on server.com when it tries to make the TCP connection to the target of the tunnel. "Connection refused" means that a connection attempt was rejected. The simplest explanation for the rejection is that, on server.com, there's nothing listening for connections on localhost port 8783. In other words, the server software that you were trying to tunnel to isn't running, or else it is running but it's not listening on that port.
Difference between clean, gradlew clean
You should use this one too:
./gradlew :app:dependencies
(Mac and Linux) -With ./
gradlew :app:dependencies
(Windows) -Without ./
The libs you are using internally using any other versions of google play service.If yes then remove or update those libs.
How to get the innerHTML of selectable jquery element?
The parameter ui
has a property called selected
which is a reference to the selected dom element, you can call innerHTML
on that element.
Your code $('.ui-selected').innerHTML
tries to return the innerHTML
property of a jQuery wrapper element for a dom element with class ui-selected
$(function () {
$("#select-image").selectable({
selected: function (event, ui) {
var $variable = ui.selected.innerHTML; // or $(ui.selected).html()
console.log($variable);
}
});
});
Demo: Fiddle
Java dynamic array sizes?
Yes, we can do this way.
import java.util.Scanner;
public class Collection_Basic {
private static Scanner sc;
public static void main(String[] args) {
Object[] obj=new Object[4];
sc = new Scanner(System.in);
//Storing element
System.out.println("enter your element");
for(int i=0;i<4;i++){
obj[i]=sc.nextInt();
}
/*
* here, size reaches with its maximum capacity so u can not store more element,
*
* for storing more element we have to create new array Object with required size
*/
Object[] tempObj=new Object[10];
//copying old array to new Array
int oldArraySize=obj.length;
int i=0;
for(;i<oldArraySize;i++){
tempObj[i]=obj[i];
}
/*
* storing new element to the end of new Array objebt
*/
tempObj[i]=90;
//assigning new array Object refeence to the old one
obj=tempObj;
for(int j=0;j<obj.length;j++){
System.out.println("obj["+j+"] -"+obj[j]);
}
}
}
how to loop through rows columns in excel VBA Macro
Here is my sugestion:
Dim i As integer, j as integer
With Worksheets("TimeOut")
i = 26
Do Until .Cells(8, i).Value = ""
For j = 9 to 100 ' I do not know how many rows you will need it.'
.Cells(j, i).Formula = "YourVolFormulaHere"
.Cells(j, i + 1).Formula = "YourCapFormulaHere"
Next j
i = i + 2
Loop
End With
Creating a UICollectionView programmatically
You can handle custom cell in uicollection view see below code.
- (void)viewDidLoad
{
UINib *nib2 = [UINib nibWithNibName:@"YourCustomCell" bundle:nil];
[CollectionVW registerNib:nib2 forCellWithReuseIdentifier:@"YourCustomCell"];
UICollectionViewFlowLayout *flowLayout = [[UICollectionViewFlowLayout alloc] init];
[flowLayout setItemSize:CGSizeMake(200, 230)];
flowLayout.minimumInteritemSpacing = 0;
[flowLayout setScrollDirection:UICollectionViewScrollDirectionVertical];
[CollectionVW setCollectionViewLayout:flowLayout];
[CollectionVW reloadData];
}
#pragma mark - COLLECTIONVIEW
#pragma mark Collection View CODE
-(NSInteger)numberOfSectionsInCollectionView:(UICollectionView *)collectionView
{
return 1;
}
- (NSInteger)collectionView:(UICollectionView *)collectionView numberOfItemsInSection:(NSInteger)section
{
return Array.count;
}
- (UICollectionViewCell *)collectionView:(UICollectionView *)collectionView cellForItemAtIndexPath:(NSIndexPath *)indexPath
{
static NSString *cellIdentifier = @"YourCustomCell";
YourCustomCell *cell = (YourCustomCell *)[collectionView dequeueReusableCellWithReuseIdentifier:cellIdentifier forIndexPath:indexPath];
cell.MainIMG.image=[UIImage imageNamed:[Array objectAtIndex:indexPath.row]];
return cell;
}
-(void)collectionView:(UICollectionView *)collectionView didSelectItemAtIndexPath:(NSIndexPath *)indexPath
{
}
#pragma mark Collection view layout things
// Layout: Set cell size
- (CGSize)collectionView:(UICollectionView *)collectionView layout:(UICollectionViewLayout*)collectionViewLayout sizeForItemAtIndexPath:(NSIndexPath *)indexPath
{
CGSize mElementSize;
mElementSize=CGSizeMake(kScreenWidth/3.4, 150);
return mElementSize;
}
- (CGFloat)collectionView:(UICollectionView *)collectionView layout:(UICollectionViewLayout*)collectionViewLayout minimumLineSpacingForSectionAtIndex:(NSInteger)section
{
return 5.0;
}
// Layout: Set Edges
- (UIEdgeInsets)collectionView: (UICollectionView *)collectionView layout:(UICollectionViewLayout*)collectionViewLayout insetForSectionAtIndex:(NSInteger)section
{
if (isIphone5 || isiPhone4)
{
return UIEdgeInsetsMake(15,15,5,15); // top, left, bottom, right
}
else if (isIphone6)
{
return UIEdgeInsetsMake(15,15,5,15); // top, left, bottom, right
}
else if (isIphone6P)
{
return UIEdgeInsetsMake(15,15,5,15); // top, left, bottom, right
}
return UIEdgeInsetsMake(15,15,5,15); // top, left, bottom, right
}
C++: variable 'std::ifstream ifs' has initializer but incomplete type
This seems to be answered - #include <fstream>
.
The message means :-
incomplete type
- the class has not been defined with a full class. The compiler has seen statements such as class ifstream;
which allow it to understand that a class exists, but does not know how much memory the class takes up.
The forward declaration allows the compiler to make more sense of :-
void BindInput( ifstream & inputChannel );
It understands the class exists, and can send pointers and references through code without being able to create the class, see any data within the class, or call any methods of the class.
The has initializer
seems a bit extraneous, but is saying that the incomplete object is being created.
How to change font-color for disabled input?
It seems nobody found a solution for this. I don't have one based on only css neither but by using this JavaScript trick I usually can handle disabled input fields.
Remember that disabled fields always follow the style that they got before becoming disabled. So the trick would be 1- Enabling them 2-Change the class 3- Disable them again. Since this happens very fast user cannot understand what happened.
A simple JavaScript code would be something like:
function changeDisabledClass (id, disabledClass){
var myInput=document.getElementById(id);
myInput.disabled=false; //First make sure it is not disabled
myInput.className=disabledClass; //change the class
myInput.disabled=true; //Re-disable it
}
Cannot read property 'map' of undefined
I considered giving a comment under the answer by taggon to this very question, but well, i felt it owed more explanation for those interested in details.
Uncaught TypeError: Cannot read property 'value' of undefined is strictly a JavaScript error.
(Note that value can be anything, but for this question value is 'map')
It's critical to understand that point, just so you avoid endless debugging cycles.
This error is common especially if just starting out in JavaScript (and it's libraries/frameworks).
For React
, this has a lot to do with understanding the component lifecycle methods.
// Follow this example to get the context
// Ignore any complexity, focus on how 'props' are passed down to children
import React, { useEffect } from 'react'
// Main component
const ShowList = () => {
// Similar to componentDidMount and componentDidUpdate
useEffect(() => {// dispatch call to fetch items, populate the redux-store})
return <div><MyItems items={movies} /></div>
}
// other component
const MyItems = props =>
<ul>
{props.items.map((item, i) => <li key={i}>item</li>)}
</ul>
/**
The above code should work fine, except for one problem.
When compiling <ShowList/>,
React-DOM renders <MyItems> before useEffect (or componentDid...) is called.
And since `items={movies}`, 'props.items' is 'undefined' at that point.
Thus the error message 'Cannot read property map of undefined'
*/
As a way to tackle this problem, @taggon gave a solution (see first anwser or link).
Solution: Set an initial/default value.
In our example, we can avoid items
being 'undefined' by declaring a default
value of an empty array.
Why? This allows React-DOM to render an empty list initially.
And when the useEffect
or componentDid...
method is executed, the component is re-rendered with a populated list of items.
// Let's update our 'other' component
// destructure the `items` and initialize it as an array
const MyItems = ({items = []}) =>
<ul>
{items.map((item, i) => <li key={i}>item</li>)}
</ul>
Kubernetes service external ip pending
If you are not using GCE or EKS (you used kubeadm
) you can add an externalIPs
spec to your service YAML. You can use the IP associated with your node's primary interface such as eth0
. You can then access the service externally, using the external IP of the node.
...
spec:
type: LoadBalancer
externalIPs:
- 192.168.0.10
Set ImageView width and height programmatically?
The best and easiest way to set a button dynamically is
Button index=new Button(this);
int height = (int) TypedValue.applyDimension(TypedValue.COMPLEX_UNIT_DIP, 45, getResources().getDisplayMetrics());
int width = (int) TypedValue.applyDimension(TypedValue.COMPLEX_UNIT_DIP, 42, getResources().getDisplayMetrics());
The above height and width are in pixels px. 45 being the height in dp and 42 being the width in dp.
index.setLayoutParams(new <Parent>.LayoutParams(width, height));
So, for example, if you've placed your button within a TableRow within a TableLayout, you should have it as TableRow.LayoutParams
index.setLayoutParams(new TableRow.LayoutParams(width, height));
How to convert list of numpy arrays into single numpy array?
Starting in NumPy version 1.10, we have the method stack. It can stack arrays of any dimension (all equal):
# List of arrays.
L = [np.random.randn(5,4,2,5,1,2) for i in range(10)]
# Stack them using axis=0.
M = np.stack(L)
M.shape # == (10,5,4,2,5,1,2)
np.all(M == L) # == True
M = np.stack(L, axis=1)
M.shape # == (5,10,4,2,5,1,2)
np.all(M == L) # == False (Don't Panic)
# This are all true
np.all(M[:,0,:] == L[0]) # == True
all(np.all(M[:,i,:] == L[i]) for i in range(10)) # == True
Enjoy,
Multi-key dictionary in c#?
I use a Tuple
as the keys in a Dictionary
.
public class Tuple<T1, T2> {
public T1 Item1 { get; private set; }
public T2 Item2 { get; private set; }
// implementation details
}
Be sure to override Equals
and GetHashCode
and define operator!=
and operator==
as appropriate. You can expand the Tuple
to hold more items as needed. .NET 4.0 will include a built-in Tuple
.
How can I compile and run c# program without using visual studio?
Another option is an interesting open source project called ScriptCS. It uses some crafty techniques to allow you a development experience outside of Visual Studio while still being able to leverage NuGet to manage your dependencies. It's free, very easy to install using Chocolatey. You can check it out here http://scriptcs.net.
Another cool feature it has is the REPL from the command line. Which allows you to do stuff like this:
C:\> scriptcs
scriptcs (ctrl-c or blank to exit)
> var message = "Hello, world!";
> Console.WriteLine(message);
Hello, world!
>
C:\>
You can create C# utility "scripts" which can be anything from small system tasks, to unit tests, to full on Web APIs. In the latest release I believe they're also allowing for hosting the runtime in your own apps.
Check out it development on the GitHub page too https://github.com/scriptcs/scriptcs
Export DataBase with MySQL Workbench with INSERT statements
For older versions:
Open MySQL Workbench > Home > Manage Import / Export (Right bottom) / Select Required DB > Advance Exports Options Tab >Complete Insert [Checked] > Start Export.
For 6.1 and beyond, thanks to ryandlf:
Click the management tab (beside schemas) and choose Data Export.
Is it possible to insert multiple rows at a time in an SQLite database?
The problem with using transaction is that you lock the table also for reading. So if you have really much data to insert and you need to access to your data, for exemple a preview or so, this way doesn't work well.
The problem with the other solution is that you lose the order of the inserting
insert into mytable (col)
select 'c'
union
select 'd'
union
select 'a'
union
select 'b';
In the sqlite the data will be store a,b,c,d...
Any way to replace characters on Swift String?
A category that modifies an existing mutable String:
extension String
{
mutating func replace(originalString:String, withString newString:String)
{
let replacedString = self.stringByReplacingOccurrencesOfString(originalString, withString: newString, options: nil, range: nil)
self = replacedString
}
}
Use:
name.replace(" ", withString: "+")
How do I make a https post in Node Js without any third party module?
For example, like this:
const querystring = require('querystring');
const https = require('https');
var postData = querystring.stringify({
'msg' : 'Hello World!'
});
var options = {
hostname: 'posttestserver.com',
port: 443,
path: '/post.php',
method: 'POST',
headers: {
'Content-Type': 'application/x-www-form-urlencoded',
'Content-Length': postData.length
}
};
var req = https.request(options, (res) => {
console.log('statusCode:', res.statusCode);
console.log('headers:', res.headers);
res.on('data', (d) => {
process.stdout.write(d);
});
});
req.on('error', (e) => {
console.error(e);
});
req.write(postData);
req.end();
if-else statement inside jsx: ReactJS
Just Tried that:
return(
<>
{
main-condition-1 &&
main-condition-2 &&
(sub-condition ? (<p>Hi</p>) : (<p>Hello</p>))
}
</>
)
Let me know what you guys think!!!
Equal height rows in a flex container
You can accomplish that now with display: grid
:
_x000D_
_x000D_
.list {_x000D_
display: grid;_x000D_
overflow: hidden;_x000D_
grid-template-columns: repeat(3, 1fr);_x000D_
grid-auto-rows: 1fr;_x000D_
grid-column-gap: 5px;_x000D_
grid-row-gap: 5px;_x000D_
max-width: 500px;_x000D_
}_x000D_
.list-item {_x000D_
background-color: #ccc;_x000D_
display: flex;_x000D_
padding: 0.5em;_x000D_
margin-bottom: 20px;_x000D_
}_x000D_
.list-content {_x000D_
width: 100%;_x000D_
}
_x000D_
<ul class="list">_x000D_
<li class="list-item">_x000D_
<div class="list-content">_x000D_
<h2>box 1</h2>_x000D_
<p>Lorem ipsum dolor sit amet, consectetur adipisicing elit.</p>_x000D_
</div>_x000D_
</li>_x000D_
<li class="list-item">_x000D_
<div class="list-content">_x000D_
<h3>box 2</h3>_x000D_
<p>Lorem ipsum dolor sit amet, consectetur adipisicing elit.</p>_x000D_
</div>_x000D_
</li>_x000D_
_x000D_
<li class="list-item">_x000D_
<div class="list-content">_x000D_
<h3>box 2</h3>_x000D_
<p>Lorem ipsum dolor</p>_x000D_
</div>_x000D_
</li>_x000D_
_x000D_
<li class="list-item">_x000D_
<div class="list-content">_x000D_
<h3>box 2</h3>_x000D_
<p>Lorem ipsum dolor</p>_x000D_
</div>_x000D_
</li>_x000D_
<li class="list-item">_x000D_
<div class="list-content">_x000D_
<h1>h1</h1>_x000D_
</div>_x000D_
</li>_x000D_
</ul>
_x000D_
_x000D_
_x000D_
Although the grid itself is not flexbox, it behaves very similar to a flexbox container, and the items inside the grid can be flex.
The grid layout is also very handy in the case you want responsive grids. That is, if you want the grid to have a different number of columns per row you can then just change grid-template-columns
:
grid-template-columns: repeat(1, 1fr); // 1 column
grid-template-columns: repeat(2, 1fr); // 2 columns
grid-template-columns: repeat(3, 1fr); // 3 columns
and so on...
You can mix it with media queries and change according to the size of the page.
Sadly there is still no support for container queries / element queries in the browsers (out of the box) to make it work well with changing the number of columns according to the container size, not to the page size (this would be great to use with reusable webcomponents).
More information about the grid layout:
https://developer.mozilla.org/en-US/docs/Web/CSS/CSS_Grid_Layout
Support of the Grid Layout accross browsers:
https://caniuse.com/#feat=css-grid
jQuery: read text file from file system
This doesn't work and it shouldn't because it would be a giant security hole.
Have a look at the new File System API. It allows you to request access to a virtual, sandboxed filesystem governed by the browser. You will have to request your user to "upload" their file into the sandboxed filesystem once, but afterwards you can work with it very elegantly.
While this definitely is the future, it is still highly experimental and only works in Google Chrome as far as CanIUse knows.
How can I change the color of my prompt in zsh (different from normal text)?
The answer by Bryan Oakley above has a glitch as it has already been pointed out and the solution offered by Andrew Marshall though it does not carry the glitch, nevertheless it does not make it obvious for too much customization on the colors used.
As macOS Catalina asks for zsh to be the default shell from now on, I think several more people may want to customize their prompt and might be coming here for an answer. So, I thought I would try to give a broader summary and touch upon other very closely-related notions that allow more customization.
3-Digit Codes for Various Colors.
First of all, here we can find 3-digit codes for various colors: https://unix.stackexchange.com/a/124409/194343.
For example, 214 is some kind of orange color.
Foreground and Background.
The other key information is that for Foreground and bacKground colors one can define what they want with F and K respectively. Source is zsh manual on visual effects: http://zsh.sourceforge.net/Doc/Release/Prompt-Expansion.html#Visual-effects
So, for example, the following two commands
autoload -U colors && colors
export PS1="%F{214}%K{000}%m%F{015}%K{000}:%F{039}%K{000}%~%F{015}%K{000}\$ "
present the hostname in orange with black background, followed by a colon in white with black background, followed by the current working directory in bright blue with black background, followed by the dollar sign in white with black background.
More related information is found below.
Prompt information on the right-hand side. For example, adding a timestamp. See https://superuser.com/a/1251045/290299. Of course, this can be color-coded, for example with some light blue/purple-ish color, like this:
RPROMPT="%F{111}%K{000}[%D{%f/%m/%y}|%@]"
Colors for ls
. After reading the manual for ls, one for example can activate the colors for ls
using the following two commands:
export CLICOLOR=1
export LSCOLORS=gafacadabaegedabagacad
Finally, as a last remark that I have not tested as I am happy with my configuration, another avenue might be for someone to install the port coreutils
from MacPorts and then use gdircolors
(source: https://unix.stackexchange.com/a/174596/194343). (I may edit this last part in the future as all the above are related pieces that make every-day life much more fun and easier to cope with.)
keypress, ctrl+c (or some combo like that)
You cannot use Ctrl+C by jQuery , but you can with another library which is shortcut.js
Live Demo :
Abdennour JSFiddle
$(document).ready(function() {
shortcut.add("Ctrl+C", function() {
$('span').html("?????. ??? ???? ??? ???? : Ctrl+C");
});
shortcut.add("Ctrl+V", function() {
$('span').html("?????. ??? ???? ??? ???? : Ctrl+V");
});
shortcut.add("Ctrl+X", function() {
$('span').html("?????. ??? ???? ??? ???? : Ctrl+X");
});
});
How add class='active' to html menu with php
seperate your page from nav bar.
pageOne.php:
$page="one";
include("navigation.php");
navigation.php
if($page=="one"){$oneIsActive = 'class="active"';}else{ $oneIsActive=""; }
if($page=="two"){$twoIsActive = 'class="active"';}else{ $twoIsActive=""; }
if($page=="three"){$threeIsActive = 'class="active"';}else{ $threeIsActive=""; }
<ul class="nav">
<li <?php echo $oneIsActive; ?>><a href="pageOne.php">One</a></li>
<li <?php echo $twoIsActive; ?>><a href="pageTwo.php"><a href="#">Page 2</a></li>
<li <?php echo $threeIsActive; ?>><a href="pageThree.php"><a href="#">Page 3</a></li>
</ul>
I found that I could also set the title of my pages with this method as well.
$page="one";
$title="This is page one."
include("navigation.php");
and just grab the $title var and put it in between the "title" tags. Though I am sending it to my header page above my nav bar.
Repeat String - Javascript
If you think all those prototype definitions, array creations, and join operations are overkill, just use a single line code where you need it. String S repeating N times:
for (var i = 0, result = ''; i < N; i++) result += S;
Launch programs whose path contains spaces
You van use Exec
Dim objShell
Set objShell = WScript.CreateObject( "WScript.Shell" )
objShell.Exec("c:\Program Files\Mozilla Firefox\firefox.exe")
Set objShell = Nothing
How to add a constant column in a Spark DataFrame?
Spark 2.2+
Spark 2.2 introduces typedLit
to support Seq
, Map
, and Tuples
(SPARK-19254) and following calls should be supported (Scala):
import org.apache.spark.sql.functions.typedLit
df.withColumn("some_array", typedLit(Seq(1, 2, 3)))
df.withColumn("some_struct", typedLit(("foo", 1, 0.3)))
df.withColumn("some_map", typedLit(Map("key1" -> 1, "key2" -> 2)))
Spark 1.3+ (lit
), 1.4+ (array
, struct
), 2.0+ (map
):
The second argument for DataFrame.withColumn
should be a Column
so you have to use a literal:
from pyspark.sql.functions import lit
df.withColumn('new_column', lit(10))
If you need complex columns you can build these using blocks like array
:
from pyspark.sql.functions import array, create_map, struct
df.withColumn("some_array", array(lit(1), lit(2), lit(3)))
df.withColumn("some_struct", struct(lit("foo"), lit(1), lit(.3)))
df.withColumn("some_map", create_map(lit("key1"), lit(1), lit("key2"), lit(2)))
Exactly the same methods can be used in Scala.
import org.apache.spark.sql.functions.{array, lit, map, struct}
df.withColumn("new_column", lit(10))
df.withColumn("map", map(lit("key1"), lit(1), lit("key2"), lit(2)))
To provide names for structs
use either alias
on each field:
df.withColumn(
"some_struct",
struct(lit("foo").alias("x"), lit(1).alias("y"), lit(0.3).alias("z"))
)
or cast
on the whole object
df.withColumn(
"some_struct",
struct(lit("foo"), lit(1), lit(0.3)).cast("struct<x: string, y: integer, z: double>")
)
It is also possible, although slower, to use an UDF.
Note:
The same constructs can be used to pass constant arguments to UDFs or SQL functions.
SQL Server 2008 Insert with WHILE LOOP
Assuming that ID
is an identity column:
INSERT INTO TheTable(HospitalID, Email, Description)
SELECT 32, Email, Description FROM TheTable
WHERE HospitalID <> 32
Try to avoid loops with SQL. Try to think in terms of sets instead.
Alarm Manager Example
MainActivity.java
package com.example.alarmexample;
import android.app.Activity;
import android.app.AlarmManager;
import android.app.PendingIntent;
import android.content.Intent;
import android.os.Bundle;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.EditText;
import android.widget.Toast;
public class MainActivity extends Activity {
Button b1;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
startAlert();
} public void startAlert() {
int timeInSec = 2;
Intent intent = new Intent(this, MyBroadcastReceiver.class);
PendingIntent pendingIntent = PendingIntent.getBroadcast(
this.getApplicationContext(), 234, intent, 0);
AlarmManager alarmManager = (AlarmManager) getSystemService(ALARM_SERVICE);
alarmManager.set(AlarmManager.RTC_WAKEUP, System.currentTimeMillis() + (timeInSec * 1000), pendingIntent);
Toast.makeText(this, "Alarm set to after " + i + " seconds",Toast.LENGTH_LONG).show();
}
}
MyBroadcastReceiver.java
package com.example.alarmexample;
import android.content.BroadcastReceiver;
import android.content.Context;
import android.content.Intent;
import android.media.MediaPlayer;
import android.widget.Toast;
public class MyBroadcastReceiver extends BroadcastReceiver {
MediaPlayer mp;
@Override
public void onReceive(Context context, Intent intent) {
mp=MediaPlayer.create(context, R.raw.alarm);
mp.start();
Toast.makeText(context, "Alarm", Toast.LENGTH_LONG).show();
}
}
AndroidManifest.xml
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.example.alarmexample" >
<uses-permission android:name="android.permission.VIBRATE" />
<application
android:allowBackup="true"
android:icon="@drawable/ic_launcher"
android:label="@string/app_name"
android:theme="@style/AppTheme" >
<activity
android:name="com.example.alarmexample.MainActivity"
android:label="@string/app_name" >
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
<receiver android:name="MyBroadcastReceiver" >
</receiver>
</application>
</manifest>
How to display Base64 images in HTML?
Try this one too:
let base64="iVBORw0KGgoAAAANSUhEUgAAAAUAAAAFCAYAAACNbyblAAAAHElEQVQI12P4//8/w38GIAXDIBKE0DHxgljNBAAO9TXL0Y4OHwAAAABJRU5ErkJggg==";
let buffer=Uint8Array.from(atob(base64), c => c.charCodeAt(0));
let blob=new Blob([buffer], { type: "image/gif" });
let url=URL.createObjectURL(blob);
let img=document.createElement("img");
img.src=url;
document.body.appendChild(img);
Not recommended for production as it is only compatible with modern browsers.
Creating watermark using html and css
Possibly this can be of great help for you.
div.image
{
width:500px;
height:250px;
border:2px solid;
border-color:#CD853F;
}
div.box
{
width:400px;
height:180px;
margin:30px 50px;
background-color:#ffffff;
border:1px solid;
border-color:#CD853F;
opacity:0.6;
filter:alpha(opacity=60);
}
div.box p
{
margin:30px 40px;
font-weight:bold;
color:#CD853F;
}
Check this link once.
How can I do a line break (line continuation) in Python?
From the horse's mouth: Explicit line
joining
Two or more physical lines may be
joined into logical lines using
backslash characters (\
), as follows:
when a physical line ends in a
backslash that is not part of a string
literal or comment, it is joined with
the following forming a single logical
line, deleting the backslash and the
following end-of-line character. For
example:
if 1900 < year < 2100 and 1 <= month <= 12 \
and 1 <= day <= 31 and 0 <= hour < 24 \
and 0 <= minute < 60 and 0 <= second < 60: # Looks like a valid date
return 1
A line ending in a backslash cannot
carry a comment. A backslash does not
continue a comment. A backslash does
not continue a token except for string
literals (i.e., tokens other than
string literals cannot be split across
physical lines using a backslash). A
backslash is illegal elsewhere on a
line outside a string literal.
How to print an exception in Python 3?
Here is the way I like that prints out all of the error stack.
import logging
try:
1 / 0
except Exception as _e:
# any one of the follows:
# print(logging.traceback.format_exc())
logging.error(logging.traceback.format_exc())
The output looks as the follows:
ERROR:root:Traceback (most recent call last):
File "/PATH-TO-YOUR/filename.py", line 4, in <module>
1 / 0
ZeroDivisionError: division by zero
LOGGING_FORMAT
:
LOGGING_FORMAT = '%(asctime)s\n File "%(pathname)s", line %(lineno)d\n %(levelname)s [%(message)s]'
PG::ConnectionBad - could not connect to server: Connection refused
I have managed to solve the problem by following the Chris Slade's answer, but to restart the server, I had to use the following commands:
launchctl unload ~/Library/LaunchAgents/homebrew.mxcl.postgresql.plist
launchctl load ~/Library/LaunchAgents/homebrew.mxcl.postgresql.plist
that I found here (pjammer's answer down at the bottom)
How do I measure request and response times at once using cURL?
From this brilliant blog post... https://blog.josephscott.org/2011/10/14/timing-details-with-curl/
cURL supports formatted output for the details of the request (see the cURL manpage for details, under -w, –write-out <format>
). For our purposes we’ll focus just on the timing details that are provided. Times below are in seconds.
Create a new file, curl-format.txt, and paste in:
time_namelookup: %{time_namelookup}s\n
time_connect: %{time_connect}s\n
time_appconnect: %{time_appconnect}s\n
time_pretransfer: %{time_pretransfer}s\n
time_redirect: %{time_redirect}s\n
time_starttransfer: %{time_starttransfer}s\n
----------\n
time_total: %{time_total}s\n
Make a request:
curl -w "@curl-format.txt" -o /dev/null -s "http://wordpress.com/"
Or on Windows, it's...
curl -w "@curl-format.txt" -o NUL -s "http://wordpress.com/"
What this does:
-w "@curl-format.txt"
tells cURL to use our format file
-o /dev/null
redirects the output of the request to /dev/null
-s
tells cURL not to show a progress meter
"http://wordpress.com/"
is
the URL we are requesting. Use quotes particularly if your URL has "&" query string parameters
And here is what you get back:
time_namelookup: 0.001s
time_connect: 0.037s
time_appconnect: 0.000s
time_pretransfer: 0.037s
time_redirect: 0.000s
time_starttransfer: 0.092s
----------
time_total: 0.164s
Make a Linux/Mac shortcut (alias)
alias curltime="curl -w \"@$HOME/.curl-format.txt\" -o /dev/null -s "
Then you can simply call...
curltime wordpress.org
Thanks to commenter Pete Doyle!
Make a Linux/Mac stand-alone script
This script does not require a separate .txt file to contain the formatting.
Create a new file, curltime, somewhere in your executable path, and paste in:
#!/bin/bash
curl -w @- -o /dev/null -s "$@" <<'EOF'
time_namelookup: %{time_namelookup}\n
time_connect: %{time_connect}\n
time_appconnect: %{time_appconnect}\n
time_pretransfer: %{time_pretransfer}\n
time_redirect: %{time_redirect}\n
time_starttransfer: %{time_starttransfer}\n
----------\n
time_total: %{time_total}\n
EOF
Call the same way as the alias:
curltime wordpress.org
Make a Windows shortcut (aka BAT file)
Put this command in CURLTIME.BAT (in the same folder as curl.exe)
curl -w "@%~dp0curl-format.txt" -o NUL -s %*
Then you can simply call...
curltime wordpress.org
Trying to handle "back" navigation button action in iOS
Perhaps this answers doesn't fit your explanation but question title. It's useful when you are trying to know when you tapped the back button on an UINavigationBar
.
In this case you can use UINavigationBarDelegate
protocol and implement one of this methods:
- (BOOL)navigationBar:(UINavigationBar *)navigationBar shouldPopItem:(UINavigationItem *)item;
- (void)navigationBar:(UINavigationBar *)navigationBar didPopItem:(UINavigationItem *)item;
When didPopItem
method is called, it's because you either tapped the back button or you used [UINavigationBar popNavigationItemAnimated:]
method and the navigation bar did pop the item.
Now, if you want to know what action triggered the didPopItem
method you can use a flag.
With this approach I don't need to manually add a left bar button item with an arrow image in order to make it similar to iOS back button, and be able to set my custom target/action.
Let's see an example:
I have a view controller that has a page view controller, and a custom page indicator view. I'm also using a custom UINavigationBar to display a title to know on what page am I and the back button to go back to the previous page. And I also can swipe to previous/next page on page controller.
#pragma mark - UIPageViewController Delegate Methods
- (void)pageViewController:(UIPageViewController *)pageViewController didFinishAnimating:(BOOL)finished previousViewControllers:(NSArray *)previousViewControllers transitionCompleted:(BOOL)completed {
if( completed ) {
//...
if( currentIndex > lastIndex ) {
UINavigationItem *navigationItem = [[UINavigationItem alloc] initWithTitle:@"Some page title"];
[[_someViewController navigationBar] pushNavigationItem:navigationItem animated:YES];
[[_someViewController pageControl] setCurrentPage:currentIndex];
} else {
_autoPop = YES; //We pop the item automatically from code.
[[_someViewController navigationBar] popNavigationItemAnimated:YES];
[[_someViewController pageControl] setCurrentPage:currentIndex];
}
}
}
So then I implement UINavigationBar delegate methods:
#pragma mark - UINavigationBar Delegate Methods
- (BOOL)navigationBar:(UINavigationBar *)navigationBar shouldPopItem:(UINavigationItem *)item {
if( !_autoPop ) {
//Pop by back button tap
} else {
//Pop from code
}
_autoPop = NO;
return YES;
}
In this case I used shouldPopItem
because the pop is animated and I wanted to handle the back button immediately and not to wait until transition is finished.
Generate unique random numbers between 1 and 100
This is my personal solution :
<script>
var i, k;
var numbers = new Array();
k = Math.floor((Math.random()*8));
numbers[0]=k;
for (var j=1;j<8;j++){
k = Math.floor((Math.random()*8));
i=0;
while (i < numbers.length){
if (numbers[i] == k){
k = Math.floor((Math.random()*8));
i=0;
}else {i++;}
}
numbers[j]=k;
}
for (var j=0;j<8;j++){
alert (numbers[j]);
}
</script>
It randomly generates 8 unique array values (between 0 and 7), then displays them using an alert box.
How to use PHP OPCache?
With PHP 5.6 on Amazon Linux (should be the same on RedHat or CentOS):
yum install php56-opcache
and then restart apache.
Go test string contains substring
To compare, there are more options:
import (
"fmt"
"regexp"
"strings"
)
const (
str = "something"
substr = "some"
)
// 1. Contains
res := strings.Contains(str, substr)
fmt.Println(res) // true
// 2. Index: check the index of the first instance of substr in str, or -1 if substr is not present
i := strings.Index(str, substr)
fmt.Println(i) // 0
// 3. Split by substr and check len of the slice, or length is 1 if substr is not present
ss := strings.Split(str, substr)
fmt.Println(len(ss)) // 2
// 4. Check number of non-overlapping instances of substr in str
c := strings.Count(str, substr)
fmt.Println(c) // 1
// 5. RegExp
matched, _ := regexp.MatchString(substr, str)
fmt.Println(matched) // true
// 6. Compiled RegExp
re = regexp.MustCompile(substr)
res = re.MatchString(str)
fmt.Println(res) // true
Benchmarks:
Contains
internally calls Index
, so the speed is almost the same (btw Go 1.11.5 showed a bit bigger difference than on Go 1.14.3).
BenchmarkStringsContains-4 100000000 10.5 ns/op 0 B/op 0 allocs/op
BenchmarkStringsIndex-4 117090943 10.1 ns/op 0 B/op 0 allocs/op
BenchmarkStringsSplit-4 6958126 152 ns/op 32 B/op 1 allocs/op
BenchmarkStringsCount-4 42397729 29.1 ns/op 0 B/op 0 allocs/op
BenchmarkStringsRegExp-4 461696 2467 ns/op 1326 B/op 16 allocs/op
BenchmarkStringsRegExpCompiled-4 7109509 168 ns/op 0 B/op 0 allocs/op
Multi-line strings in PHP
To put the strings "l" and "vv" on separate lines in the code alone:
$xml = "l";
$xml .= "vv"
echo $xml;
In this instance you're saying to append .=
the string to the end of the previous version of that string variable. Remember that = is only an assignment operator so in your original code you're assigning the variable a new string value.
To put the strings "l" and "vv" on separate lines in the echo alone:
$xml = "l\nvv"
echo $xml;
You don't need multiple strings in this instance, as the new line character \n
will take care of that for you.
To put the strings "l" and "vv" on separate lines in code and when echoing:
$xml = "l";
$xml .= "\nvv"
echo $xml;
Select Last Row in the Table
To get last record details
Model::all()->last();
or
Model::orderBy('id', 'desc')->first();
To get last record id
Model::all()->last()->id;
or
Model::orderBy('id', 'desc')->first()->id;
E: Unable to locate package npm
in my jenkins/jenkins docker sudo always generates error:
bash: sudo: command not found
I needed update repo list with:
curl -sL https://deb.nodesource.com/setup_10.x | apt-get update
then,
apt-get install nodejs
All the command line results like this:
root@76e6f92724d1:/# curl -sL https://deb.nodesource.com/setup_10.x | apt-get update
Ign:1 http://deb.debian.org/debian stretch InRelease
Get:2 http://security.debian.org/debian-security stretch/updates InRelease [94.3 kB]
Get:3 http://deb.debian.org/debian stretch-updates InRelease [91.0 kB]
Get:4 http://deb.debian.org/debian stretch Release [118 kB]
Get:5 http://security.debian.org/debian-security stretch/updates/main amd64 Packages [520 kB]
Get:6 http://deb.debian.org/debian stretch-updates/main amd64 Packages [27.9 kB]
Get:8 http://deb.debian.org/debian stretch Release.gpg [2410 B]
Get:9 http://deb.debian.org/debian stretch/main amd64 Packages [7083 kB]
Get:7 https://packagecloud.io/github/git-lfs/debian stretch InRelease [23.2 kB]
Get:10 https://packagecloud.io/github/git-lfs/debian stretch/main amd64 Packages [4675 B]
Fetched 7965 kB in 20s (393 kB/s)
Reading package lists... Done
root@76e6f92724d1:/# apt-get install nodejs
Reading package lists... Done
Building dependency tree
Reading state information... Done
The following additional packages will be installed:
libicu57 libuv1
The following NEW packages will be installed:
libicu57 libuv1 nodejs
0 upgraded, 3 newly installed, 0 to remove and 0 not upgraded.
Need to get 11.2 MB of archives.
After this operation, 45.2 MB of additional disk space will be used.
Do you want to continue? [Y/n] y
Get:1 http://deb.debian.org/debian stretch/main amd64 libicu57 amd64 57.1-6+deb9u3 [7705 kB]
Get:2 http://deb.debian.org/debian stretch/main amd64 libuv1 amd64 1.9.1-3 [84.4 kB]
Get:3 http://deb.debian.org/debian stretch/main amd64 nodejs amd64 4.8.2~dfsg-1 [3440 kB]
Fetched 11.2 MB in 26s (418 kB/s)
debconf: delaying package configuration, since apt-utils is not installed
Selecting previously unselected package libicu57:amd64.
(Reading database ... 12488 files and directories currently installed.)
Preparing to unpack .../libicu57_57.1-6+deb9u3_amd64.deb ...
Unpacking libicu57:amd64 (57.1-6+deb9u3) ...
Selecting previously unselected package libuv1:amd64.
Preparing to unpack .../libuv1_1.9.1-3_amd64.deb ...
Unpacking libuv1:amd64 (1.9.1-3) ...
Selecting previously unselected package nodejs.
Preparing to unpack .../nodejs_4.8.2~dfsg-1_amd64.deb ...
Unpacking nodejs (4.8.2~dfsg-1) ...
Setting up libuv1:amd64 (1.9.1-3) ...
Setting up libicu57:amd64 (57.1-6+deb9u3) ...
Processing triggers for libc-bin (2.24-11+deb9u4) ...
Setting up nodejs (4.8.2~dfsg-1) ...
update-alternatives: using /usr/bin/nodejs to provide /usr/bin/js (js) in auto mode
Inner join vs Where
I have an addition to that good answer:
That's what is defined as SQL92 and SQL89 respectively, there is no performance difference between them although you can omit the word INNER (using just JOIN is clear enough and in the simplest query you save 5 keyboard strokes now imagine how many strokes there are in big ones).
In Javascript, how do I check if an array has duplicate values?
If you have an ES2015 environment (as of this writing: io.js, IE11, Chrome, Firefox, WebKit nightly), then the following will work, and will be fast (viz. O(n)):
function hasDuplicates(array) {
return (new Set(array)).size !== array.length;
}
If you only need string values in the array, the following will work:
function hasDuplicates(array) {
var valuesSoFar = Object.create(null);
for (var i = 0; i < array.length; ++i) {
var value = array[i];
if (value in valuesSoFar) {
return true;
}
valuesSoFar[value] = true;
}
return false;
}
We use a "hash table" valuesSoFar
whose keys are the values we've seen in the array so far. We do a lookup using in
to see if that value has been spotted already; if so, we bail out of the loop and return true
.
If you need a function that works for more than just string values, the following will work, but isn't as performant; it's O(n2) instead of O(n).
function hasDuplicates(array) {
var valuesSoFar = [];
for (var i = 0; i < array.length; ++i) {
var value = array[i];
if (valuesSoFar.indexOf(value) !== -1) {
return true;
}
valuesSoFar.push(value);
}
return false;
}
The difference is simply that we use an array instead of a hash table for valuesSoFar
, since JavaScript "hash tables" (i.e. objects) only have string keys. This means we lose the O(1) lookup time of in
, instead getting an O(n) lookup time of indexOf
.
MySql: is it possible to 'SUM IF' or to 'COUNT IF'?
you want something like:
SELECT count(id), SUM(hour) as totHour, SUM(kind=1) as countKindOne;
Note that your second example was close, but the IF() function always takes three arguments, so it would have had to be COUNT(IF(kind=1,1,NULL))
. I prefer the SUM() syntax shown above because it's concise.
take(1) vs first()
Tip: Only use first()
if:
- You consider zero items emitted to be an error condition (eg. completing before emitting) AND if there’s a greater than 0% chance of error you handling it gracefully
- OR You know 100% that the source observable will emit 1+ items (so can never throw).
If there are zero emissions and you are not explicitly handling it (with catchError
) then that error will get propagated up, possibly cause an unexpected problem somewhere else and can be quite tricky to track down - especially if it's coming from an end user.
You're safer off using take(1)
for the most part provided that:
- You're OK with
take(1)
not emitting anything if the source completes without an emission.
- You don't need to use an inline predicate (eg.
first(x => x > 10)
)
Note: You can use a predicate with take(1)
like this: .pipe( filter(x => x > 10), take(1) )
. There is no error with this if nothing is ever greater than 10.
What about single()
If you want to be even stricter, and disallow two emissions you can use single()
which errors if there are zero or 2+ emissions. Again you'd need to handle errors in that case.
Tip: Single
can occasionally be useful if you want to ensure your observable chain isn't doing extra work like calling an http service twice and emitting two observables. Adding single
to the end of the pipe will let you know if you made such a mistake. I'm using it in a 'task runner' where you pass in a task observable that should only emit one value, so I pass the response through single(), catchError()
to guarantee good behavior.
Why not always use first()
instead of take(1)
?
aka. How can first
potentially cause more errors?
If you have an observable that takes something from a service and then pipes it through first()
you should be fine most of the time. But if someone comes along to disable the service for whatever reason - and changes it to emit of(null)
or NEVER
then any downstream first()
operators would start throwing errors.
Now I realize that might be exactly what you want - hence why this is just a tip. The operator first
appealed to me because it sounded slightly less 'clumsy' than take(1)
but you need to be careful about handling errors if there's ever a chance of the source not emitting. Will entirely depend on what you're doing though.
If you have a default value (constant):
Consider also .pipe(defaultIfEmpty(42), first())
if you have a default value that should be used if nothing is emitted. This would of course not raise an error because first
would always receive a value.
Note that defaultIfEmpty
is only triggered if the stream is empty, not if the value of what is emitted is null
.
A general tree implementation?
anytree
I recommend https://pypi.python.org/pypi/anytree
Example
from anytree import Node, RenderTree
udo = Node("Udo")
marc = Node("Marc", parent=udo)
lian = Node("Lian", parent=marc)
dan = Node("Dan", parent=udo)
jet = Node("Jet", parent=dan)
jan = Node("Jan", parent=dan)
joe = Node("Joe", parent=dan)
print(udo)
Node('/Udo')
print(joe)
Node('/Udo/Dan/Joe')
for pre, fill, node in RenderTree(udo):
print("%s%s" % (pre, node.name))
Udo
+-- Marc
¦ +-- Lian
+-- Dan
+-- Jet
+-- Jan
+-- Joe
print(dan.children)
(Node('/Udo/Dan/Jet'), Node('/Udo/Dan/Jan'), Node('/Udo/Dan/Joe'))
Features
anytree has also a powerful API with:
- simple tree creation
- simple tree modification
- pre-order tree iteration
- post-order tree iteration
- resolve relative and absolute node paths
- walking from one node to an other.
- tree rendering (see example above)
- node attach/detach hookups
How to convert JSON string into List of Java object?
You can also use Gson for this scenario.
Gson gson = new Gson();
NameList nameList = gson.fromJson(data, NameList.class);
List<Name> list = nameList.getList();
Your NameList class could look like:
class NameList{
List<Name> list;
//getter and setter
}
How to host material icons offline?
I'm building for Angular 4/5 and often working offline and so the following worked for me. First install the NPM:
npm install material-design-icons --save
Then add the following to styles.css:
@import '~material-design-icons/iconfont/material-icons.css';
close vs shutdown socket?
This may be platform specific, I somehow doubt it, but anyway, the best explanation I've seen is here on this msdn page where they explain about shutdown, linger options, socket closure and general connection termination sequences.
In summary, use shutdown to send a shutdown sequence at the TCP level and use close to free up the resources used by the socket data structures in your process. If you haven't issued an explicit shutdown sequence by the time you call close then one is initiated for you.
How to use phpexcel to read data and insert into database?
if($this->mng_auth->get_language()=='en')
{
$excel->getActiveSheet()->setRightToLeft(false);
}
else
{
$excel->getActiveSheet()->setRightToLeft(true);
}
$styleArray = array(
'borders' => array(
'allborders' => array(
'style' => PHPExcel_Style_Border::BORDER_THIN,
'color' => array('argb' => '00000000'),
),
),
);
//SET property
$objPHPExcel->getActiveSheet()->getStyle('A1:M10001')->applyFromArray($styleArray);
$objPHPExcel->getActiveSheet()->getStyle('A1:M10001')->getAlignment()->setWrapText(true);
$objPHPExcel->getActiveSheet()->getStyle('A1:'.chr(65+count($fields)-1).$query->num_rows())->applyFromArray($styleArray);
$objPHPExcel->getActiveSheet()->getStyle('A1:'.chr(65+count($fields)-1).$query->num_rows())->getAlignment()->setWrapText(true);
What is the best way to call a script from another script?
This is an example with subprocess
library:
import subprocess
python_version = '3'
path_to_run = './'
py_name = '__main__.py'
# args = [f"python{python_version}", f"{path_to_run}{py_name}"] # Avaible in python3
args = ["python{}".format(python_version), "{}{}".format(path_to_run, py_name)]
res = subprocess.Popen(args, stdout=subprocess.PIPE)
output, error_ = res.communicate()
if not error_:
print(output)
else:
print(error_)
exclude @Component from @ComponentScan
I needed to exclude an auditing @Aspect @Component from the app context but only for a few test classes. I ended up using @Profile("audit") on the aspect class; including the profile for normal operations but excluding it (don't put it in @ActiveProfiles) on the specific test classes.
How to scale images to screen size in Pygame
If you scale 1600x900
to 1280x720
you have
scale_x = 1280.0/1600
scale_y = 720.0/900
Then you can use it to find button size, and button position
button_width = 300 * scale_x
button_height = 300 * scale_y
button_x = 1440 * scale_x
button_y = 860 * scale_y
If you scale 1280x720
to 1600x900
you have
scale_x = 1600.0/1280
scale_y = 900.0/720
and rest is the same.
I add .0
to value to make float
- otherwise scale_x
, scale_y
will be rounded to integer
- in this example to 0
(zero) (Python 2.x)
Convert timestamp to readable date/time PHP
$timestamp = 1465298940;
$datetimeFormat = 'Y-m-d H:i:s';
$date = new \DateTime();
// If you must have use time zones
// $date = new \DateTime('now', new \DateTimeZone('Europe/Helsinki'));
$date->setTimestamp($timestamp);
echo $date->format($datetimeFormat);
result: 2016-06-07 14:29:00
Other time zones:
Delete statement in SQL is very slow
Things that can cause a delete to be slow:
- deleting a lot of records
- many indexes
- missing indexes on foreign keys in child tables. (thank you to @CesarAlvaradoDiaz for mentioning this in the comments)
- deadlocks and blocking
- triggers
- cascade delete (those ten parent records you are deleting could mean
millions of child records getting deleted)
- Transaction log needing to grow
- Many Foreign keys to check
So your choices are to find out what is blocking and fix it or run the deletes in off hours when they won't be interfering with the normal production load. You can run the delete in batches (useful if you have triggers, cascade delete, or a large number of records). You can drop and recreate the indexes (best if you can do that in off hours too).
Row count with PDO
Use parameter array(PDO::ATTR_CURSOR => PDO::CURSOR_SCROLL)
, else show -1:
Usen parametro array(PDO::ATTR_CURSOR => PDO::CURSOR_SCROLL)
, sin ello sale -1
example:
$res1 = $mdb2->prepare("SELECT clave FROM $tb WHERE id_usuario='$username' AND activo=1 and id_tipo_usuario='4'", array(PDO::ATTR_CURSOR => PDO::CURSOR_SCROLL));
$res1->execute();
$count=$res1->rowCount();
echo $count;
Java Spring - How to use classpath to specify a file location?
Are we talking about standard java.io.FileReader
? Won't work, but it's not hard without it.
/src/main/resources
maven directory contents are placed in the root of your CLASSPATH, so you can simply retrieve it using:
InputStream is = getClass().getResourceAsStream("/storedProcedures.sql");
If the result is not null
(resource not found), feel free to wrap it in a reader:
Reader reader = new InputStreamReader(is);
Pandas: Convert Timestamp to datetime.date
Assume time column is in timestamp integer msec format
1 day = 86400000 ms
Here you go:
day_divider = 86400000
df['time'] = df['time'].values.astype(dtype='datetime64[ms]') # for msec format
df['time'] = (df['time']/day_divider).values.astype(dtype='datetime64[D]') # for day format
How to convert InputStream to FileInputStream
Use ClassLoader#getResource()
instead if its URI represents a valid local disk file system path.
URL resource = classLoader.getResource("resource.ext");
File file = new File(resource.toURI());
FileInputStream input = new FileInputStream(file);
// ...
If it doesn't (e.g. JAR), then your best bet is to copy it into a temporary file.
Path temp = Files.createTempFile("resource-", ".ext");
Files.copy(classLoader.getResourceAsStream("resource.ext"), temp, StandardCopyOption.REPLACE_EXISTING);
FileInputStream input = new FileInputStream(temp.toFile());
// ...
That said, I really don't see any benefit of doing so, or it must be required by a poor helper class/method which requires FileInputStream
instead of InputStream
. If you can, just fix the API to ask for an InputStream
instead. If it's a 3rd party one, by all means report it as a bug. I'd in this specific case also put question marks around the remainder of that API.
Difference in months between two dates
I just needed something simple to cater for e.g. employment dates where only the month/year is entered, so wanted distinct years and months worked in. This is what I use, here for usefullness only
public static YearsMonths YearMonthDiff(DateTime startDate, DateTime endDate) {
int monthDiff = ((endDate.Year * 12) + endDate.Month) - ((startDate.Year * 12) + startDate.Month) + 1;
int years = (int)Math.Floor((decimal) (monthDiff / 12));
int months = monthDiff % 12;
return new YearsMonths {
TotalMonths = monthDiff,
Years = years,
Months = months
};
}
.NET Fiddle
How do you run `apt-get` in a dockerfile behind a proxy?
UPDATE:
You have wrong capitalization of environment variables in ENV. Correct one is http_proxy
. Your example should be:
FROM ubuntu:13.10
ENV http_proxy <HTTP_PROXY>
ENV https_proxy <HTTPS_PROXY>
RUN apt-get update && apt-get upgrade
or
FROM centos
ENV http_proxy <HTTP_PROXY>
ENV https_proxy <HTTPS_PROXY>
RUN yum update
All variables specified in ENV are prepended to every RUN command. Every RUN command is executed in own container/environment, so it does not inherit variables from previous RUN commands!
Note: There is no need to call docker daemon with proxy for this to work, although if you want to pull images etc. you need to set the proxy for docker deamon too. You can set proxy for daemon in /etc/default/docker
in Ubuntu (it does not affect containers setting).
Also, this can happen in case you run your proxy on host (i.e. localhost, 127.0.0.1). Localhost on host differ from localhost in container. In such case, you need to use another IP (like 172.17.42.1) to bind your proxy to or if you bind to 0.0.0.0, you can use 172.17.42.1 instead of 127.0.0.1 for connection from container during docker build
.
You can also look for an example here: How to rebuild dockerfile quick by using cache?
How do you implement a Stack and a Queue in JavaScript?
Here is my Implementation of Stacks.
function Stack() {
this.dataStore = [];
this.top = 0;
this.push = push;
this.pop = pop;
this.peek = peek;
this.clear = clear;
this.length = length;
}
function push(element) {
this.dataStore[this.top++] = element;
}
function peek() {
return this.dataStore[this.top-1];
}
function pop() {
return this.dataStore[--this.top];
}
function clear() {
this.top = 0;
}
function length() {
return this.top;
}
var s = new Stack();
s.push("David");
s.push("Raymond");
s.push("Bryan");
console.log("length: " + s.length());
console.log(s.peek());
How can I measure the actual memory usage of an application or process?
If you want something quicker than profiling with Valgrind and your kernel is older and you can't use smaps, a ps with the options to show the resident set of the process (with ps -o rss,command
) can give you a quick and reasonable _aproximation_
of the real amount of non-swapped memory being used.
How to set array length in c# dynamically
Typically, arrays require constants to initialize their size. You could sweep over nvPairs once to get the length, then "dynamically" create an array using a variable for length like this.
InputProperty[] ip = (InputProperty[])Array.CreateInstance(typeof(InputProperty), length);
I wouldn't recommend it, though. Just stick with the
List<InputProperty> ip = ...
...
update.Items = ip.ToArray();
solution. It's not that much less performant, and way better looking.
How to upper case every first letter of word in a string?
import org.apache.commons.lang.WordUtils;
public class CapitalizeFirstLetterInString {
public static void main(String[] args) {
// only the first letter of each word is capitalized.
String wordStr = WordUtils.capitalize("this is first WORD capital test.");
//Capitalize method capitalizes only first character of a String
System.out.println("wordStr= " + wordStr);
wordStr = WordUtils.capitalizeFully("this is first WORD capital test.");
// This method capitalizes first character of a String and make rest of the characters lowercase
System.out.println("wordStr = " + wordStr );
}
}
Output :
This Is First WORD Capital Test.
This Is First Word Capital Test.
How to conditional format based on multiple specific text in Excel
You can use MATCH
for instance.
Select the column from the first cell, for example cell A2 to cell A100 and insert a conditional formatting, using 'New Rule...' and the option to conditional format based on a formula.
In the entry box, put:
=MATCH(A2, 'Sheet2'!A:A, 0)
Pick the desired formatting (change the font to red or fill the cell background, etc) and click OK.
MATCH
takes the value A2
from your data table, looks into 'Sheet2'!A:A
and if there's an exact match (that's why there's a 0
at the end), then it'll return the row number.
Note: Conditional formatting based on conditions from other sheets is available only on Excel 2010 onwards. If you're working on an earlier version, you might want to get the list of 'Don't check' in the same sheet.
EDIT: As per new information, you will have to use some reverse matching. Instead of the above formula, try:
=SUM(IFERROR(SEARCH('Sheet2'!$A$1:$A$44, A2),0))
Accessing Redux state in an action creator?
I would like to suggest yet another alternative that I find the cleanest, but it requires react-redux
or something simular - also I'm using a few other fancy features along the way:
// actions.js
export const someAction = (items) => ({
type: 'SOME_ACTION',
payload: {items},
});
// Component.jsx
import {connect} from "react-redux";
const Component = ({boundSomeAction}) => (<div
onClick={boundSomeAction}
/>);
const mapState = ({otherReducer: {items}}) => ({
items,
});
const mapDispatch = (dispatch) => bindActionCreators({
someAction,
}, dispatch);
const mergeProps = (mappedState, mappedDispatches) => {
// you can only use what gets returned here, so you dont have access to `items` and
// `someAction` anymore
return {
boundSomeAction: () => mappedDispatches.someAction(mappedState.items),
}
});
export const ConnectedComponent = connect(mapState, mapDispatch, mergeProps)(Component);
// (with other mapped state or dispatches) Component.jsx
import {connect} from "react-redux";
const Component = ({boundSomeAction, otherAction, otherMappedState}) => (<div
onClick={boundSomeAction}
onSomeOtherEvent={otherAction}
>
{JSON.stringify(otherMappedState)}
</div>);
const mapState = ({otherReducer: {items}, otherMappedState}) => ({
items,
otherMappedState,
});
const mapDispatch = (dispatch) => bindActionCreators({
someAction,
otherAction,
}, dispatch);
const mergeProps = (mappedState, mappedDispatches) => {
const {items, ...remainingMappedState} = mappedState;
const {someAction, ...remainingMappedDispatch} = mappedDispatch;
// you can only use what gets returned here, so you dont have access to `items` and
// `someAction` anymore
return {
boundSomeAction: () => someAction(items),
...remainingMappedState,
...remainingMappedDispatch,
}
});
export const ConnectedComponent = connect(mapState, mapDispatch, mergeProps)(Component);
If you want to reuse this you'll have to extract the specific mapState
, mapDispatch
and mergeProps
into functions to reuse elsewhere, but this makes dependencies perfectly clear.
Regular Expression for password validation
Update to Justin answer above. if you want to use it using Data Annotation in MVC you can do as follow
[RegularExpression(@"^(?=.*[a-z])(?=.*[A-Z])(?=.*\d)(?=.*[^\da-zA-Z]).{8,15}$", ErrorMessage = "Password must be between 6 and 20 characters and contain one uppercase letter, one lowercase letter, one digit and one special character.")]
UNIX export command
export
is used to set environment variables. For example:
export EDITOR=pico
Will set your default text editor to be the pico
command.
How can I check the current status of the GPS receiver?
If you just need to know if there's a fix, then check for the last known location provided by the GPS receiver and check the .getTime() value to know how old is that. If it's recent enough (like... a few seconds) you have a fix.
LocationManager lm = (LocationManager)context.getSystemService(LOCATION_SERVICE);
Location loc = lm.getLastKnownLocation(LocationManager.GPS_PROVIDER);
// Get the time of the last fix
long lastFixTimeMillis = loc.getTime();
... and finally compare that to current date time (In UTC!). If it's recent enough you have a fix.
I do that in my app and so far so good.
How to calculate cumulative normal distribution?
Here's an example:
>>> from scipy.stats import norm
>>> norm.cdf(1.96)
0.9750021048517795
>>> norm.cdf(-1.96)
0.024997895148220435
In other words, approximately 95% of the standard normal interval lies within two standard deviations, centered on a standard mean of zero.
If you need the inverse CDF:
>>> norm.ppf(norm.cdf(1.96))
array(1.9599999999999991)
How to respond with HTTP 400 error in a Spring MVC @ResponseBody method returning String?
As mentioned in some answers, there is the ability to create an exception class for each HTTP status that you want to return. I don't like the idea of having to create a class per status for each project. Here is what I came up with instead.
- Create a generic exception that accepts an HTTP status
- Create an Controller Advice exception handler
Let's get to the code
package com.javaninja.cam.exception;
import org.springframework.http.HttpStatus;
/**
* The exception used to return a status and a message to the calling system.
* @author norrisshelton
*/
@SuppressWarnings("ClassWithoutNoArgConstructor")
public class ResourceException extends RuntimeException {
private HttpStatus httpStatus = HttpStatus.INTERNAL_SERVER_ERROR;
/**
* Gets the HTTP status code to be returned to the calling system.
* @return http status code. Defaults to HttpStatus.INTERNAL_SERVER_ERROR (500).
* @see HttpStatus
*/
public HttpStatus getHttpStatus() {
return httpStatus;
}
/**
* Constructs a new runtime exception with the specified HttpStatus code and detail message.
* The cause is not initialized, and may subsequently be initialized by a call to {@link #initCause}.
* @param httpStatus the http status. The detail message is saved for later retrieval by the {@link
* #getHttpStatus()} method.
* @param message the detail message. The detail message is saved for later retrieval by the {@link
* #getMessage()} method.
* @see HttpStatus
*/
public ResourceException(HttpStatus httpStatus, String message) {
super(message);
this.httpStatus = httpStatus;
}
}
Then I create a controller advice class
package com.javaninja.cam.spring;
import com.javaninja.cam.exception.ResourceException;
import org.springframework.http.ResponseEntity;
import org.springframework.web.bind.annotation.ExceptionHandler;
/**
* Exception handler advice class for all SpringMVC controllers.
* @author norrisshelton
* @see org.springframework.web.bind.annotation.ControllerAdvice
*/
@org.springframework.web.bind.annotation.ControllerAdvice
public class ControllerAdvice {
/**
* Handles ResourceExceptions for the SpringMVC controllers.
* @param e SpringMVC controller exception.
* @return http response entity
* @see ExceptionHandler
*/
@ExceptionHandler(ResourceException.class)
public ResponseEntity handleException(ResourceException e) {
return ResponseEntity.status(e.getHttpStatus()).body(e.getMessage());
}
}
To use it
throw new ResourceException(HttpStatus.BAD_REQUEST, "My message");
http://javaninja.net/2016/06/throwing-exceptions-messages-spring-mvc-controller/
how to configure hibernate config file for sql server
The connection URL should look like this for SQL Server:
jdbc:sqlserver://serverName[\instanceName][:port][;databaseName=your_db_name]
Examples:
jdbc:sqlserver://localhost
jdbc:sqlserver://127.0.0.1\INGESQL:1433;databaseName=datatest
...
Find the least number of coins required that can make any change from 1 to 99 cents
I've been learning about dynamic programming today, and here's the result:
coins = [1,5,10,25]
d = {} # stores tuples of the form (# of coins, [coin list])
# finds the minimum # of coins needed to
# make change for some number of cents
def m(cents):
if cents in d.keys():
return d[cents]
elif cents > 0:
choices = [(m(cents - x)[0] + 1, m(cents - x)[1] + [x]) for x in coins if cents >= x]
# given a list of tuples, python's min function
# uses the first element of each tuple for comparison
d[cents] = min(choices)
return d[cents]
else:
d[0] = (0, [])
return d[0]
for x in range(1, 100):
val = m(x)
print x, "cents requires", val[0], "coins:", val[1]
Dynamic programming really is magical.
How do I remove files saying "old mode 100755 new mode 100644" from unstaged changes in Git?
The accepted answer to set git config core.filemode false
, works, but with consequences. Setting core.filemode
to false tells git to ignore any executable bit changes on the filesystem so it won't view this as a change. If you do need to stage an executable bit change for this repository anytime in the future, you would have to do it manually, or set core.filemode
back to true.
A less consequential alternative, if all the modified files should have mode 100755, is to do something like
chmod 100755 $(git ls-files --modified)
which just does exactly the change in mode, no more, no less, without additional implications.
(in my case, it was due to a OneDrive sync with my filesystem on MacOS; by not changing core.filemode
, I'm leaving the possibility open that the mode change might happen again in the future; in my case, I'd like to know if it happens again, and changing core.filemode
will hide it from me, which I don't want)
C#: How to add subitems in ListView
Suppose you have a List Collection containing many items to show in a ListView, take the following example that iterates through the List Collection:
foreach (Inspection inspection in anInspector.getInspections())
{
ListViewItem item = new ListViewItem();
item.Text=anInspector.getInspectorName().ToString();
item.SubItems.Add(inspection.getInspectionDate().ToShortDateString());
item.SubItems.Add(inspection.getHouse().getAddress().ToString());
item.SubItems.Add(inspection.getHouse().getValue().ToString("C"));
listView1.Items.Add(item);
}
That code produces the following output in the ListView (of course depending how many items you have in the List Collection):
Basically the first column is a listviewitem containing many subitems (other columns). It may seem strange but listview is very flexible, you could even build a windows-like file explorer with it!
Split string with PowerShell and do something with each token
To complement Justus Thane's helpful answer:
As Joey notes in a comment, PowerShell has a powerful, regex-based -split
operator.
- In its unary form (
-split '...'
), -split
behaves like awk
's default field splitting, which means that:
- Leading and trailing whitespace is ignored.
- Any run of whitespace (e.g., multiple adjacent spaces) is treated as a single separator.
In PowerShell v4+ an expression-based - and therefore faster - alternative to the ForEach-Object
cmdlet became available: the .ForEach()
array (collection) method, as described in this blog post (alongside the .Where()
method, a more powerful, expression-based alternative to Where-Object
).
Here's a solution based on these features:
PS> (-split ' One for the money ').ForEach({ "token: [$_]" })
token: [One]
token: [for]
token: [the]
token: [money]
Note that the leading and trailing whitespace was ignored, and that the multiple spaces between One
and for
were treated as a single separator.
How to enable CORS in ASP.net Core WebAPI
for ASP.NET Core 3.1 this soleved my Problem
https://jasonwatmore.com/post/2020/05/20/aspnet-core-api-allow-cors-requests-from-any-origin-and-with-credentials
public class Startup
{
public Startup(IConfiguration configuration)
{
Configuration = configuration;
}
public IConfiguration Configuration { get; }
// This method gets called by the runtime. Use this method to add services to the container.
public void ConfigureServices(IServiceCollection services)
{
services.AddCors();
services.AddControllers();
}
// This method gets called by the runtime. Use this method to configure the HTTP request pipeline.
public void Configure(IApplicationBuilder app, IWebHostEnvironment env)
{
app.UseRouting();
// global cors policy
app.UseCors(x => x
.AllowAnyMethod()
.AllowAnyHeader()
.SetIsOriginAllowed(origin => true) // allow any origin
.AllowCredentials()); // allow credentials
app.UseAuthentication();
app.UseAuthorization();
app.UseEndpoints(x => x.MapControllers());
}
}
Test if number is odd or even
$before = microtime(true);
$n = 1000;
$numbers = range(1,$n);
$cube_numbers = array_map('cube',$numbers);
function cube($n){
$msg ='even';
if($n%2 !=0){
$msg = 'odd';
}
return "The Number is $n is ".$msg;
}
foreach($cube_numbers as $cube){
echo $cube . "<br/>";
}
$after = microtime(true);
echo $after-$before. 'seconds';
Hibernate throws org.hibernate.AnnotationException: No identifier specified for entity: com..domain.idea.MAE_MFEView
TL;DR
You are missing the @Id
entity property, and that's why Hibernate is throwing that exception.
Entity identifiers
Any JPA entity must have an identifier property, that is marked with the Id
annotation.
There are two types of identifiers:
Assigned identifiers
An assigned identifier looks as follows:
@Id
private Long id;
Notice that we are using a wrapper (e.g., Long
, Integer
) instead of a primitive type (e.g., long
, int
).
Using a wrapper type is a better choice when using Hibernate because, by checking if the id
is null
or not, Hibernate can better determine if an entity is transient (it does not have an associated table row) or detached (it has an associated table row, but it's not managed by the current Persistence Context).
The assigned identifier must be set manually by the application prior to calling persist:
Post post = new Post();
post.setId(1L);
entityManager.persist(post);
Auto-generated identifiers
An auto-generated identifier requires the @GeneratedValue
annotation besides the @Id
:
@Id
@GeneratedValue
private int id;
There are 3 strategies Hibernate can use to auto-generate the entity identifier:
The IDENTITY
strategy is to be avoided if the underlying database supports sequences (e.g., Oracle, PostgreSQL, MariaDB since 10.3, SQL Server since 2012). The only major database that does not support sequences is MySQL.
The problem with IDENTITY
is that automatic Hibernate batch inserts are disabled for this strategy.
The SEQUENCE
strategy is the best choice unless you are using MySQL. For the SEQUENCE
strategy, you also want to use the pooled
optimizer to reduce the number of database roundtrips when persisting multiple entities in the same Persistence Context.
The TABLE
generator is a terrible choice because it does not scale. For portability, you are better off using SEQUENCE
by default and switch to IDENTITY
for MySQL only.
Get city name using geolocation
_x000D_
_x000D_
$.ajax({_x000D_
url: "https://geolocation-db.com/jsonp",_x000D_
jsonpCallback: "callback",_x000D_
dataType: "jsonp",_x000D_
success: function(location) {_x000D_
$('#country').html(location.country_name);_x000D_
$('#state').html(location.state);_x000D_
$('#city').html(location.city);_x000D_
$('#latitude').html(location.latitude);_x000D_
$('#longitude').html(location.longitude);_x000D_
$('#ip').html(location.IPv4);_x000D_
}_x000D_
});
_x000D_
<script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.1.1/jquery.min.js"></script>_x000D_
_x000D_
<div>Country: <span id="country"></span></div>_x000D_
<div>State: <span id="state"></span></div>_x000D_
<div>City: <span id="city"></span></div>_x000D_
<div>Latitude: <span id="latitude"></span></div>_x000D_
<div>Longitude: <span id="longitude"></span></div>_x000D_
<div>IP: <span id="ip"></span></div>
_x000D_
_x000D_
_x000D_
Using html5 geolocation requires user permission. In case you don't want this, go for an external locator like https://geolocation-db.com IPv6 is supported. No restrictions and unlimited requests allowed.
Example
For a pure javascript example, without using jQuery, check out this answer.
Defining lists as global variables in Python
When you assign a variable (x = ...
), you are creating a variable in the current scope (e.g. local to the current function). If it happens to shadow a variable fron an outer (e.g. global) scope, well too bad - Python doesn't care (and that's a good thing). So you can't do this:
x = 0
def f():
x = 1
f()
print x #=>0
and expect 1
. Instead, you need do declare that you intend to use the global x
:
x = 0
def f():
global x
x = 1
f()
print x #=>1
But note that assignment of a variable is very different from method calls. You can always call methods on anything in scope - e.g. on variables that come from an outer (e.g. the global) scope because nothing local shadows them.
Also very important: Member assignment (x.name = ...
), item assignment (collection[key] = ...
), slice assignment (sliceable[start:end] = ...
) and propably more are all method calls as well! And therefore you don't need global
to change a global's members or call it methods (even when they mutate the object).
How do I check if file exists in Makefile so I can delete it?
The answers like the one from @mark-wilkins using \ to continue lines and ; to terminate them in the shell or like the ones from @kenorb changing this to one line are good and will fix this problem.
there's a simpler answer to the original problem (as @alexey-polonsky pointed out). Use the -f flag to rm so that it won't trigger an error
rm -f myApp
this is simpler, faster and more reliable. Just be careful not to end up with a slash and an empty variable
rm -f /$(myAppPath) #NEVER DO THIS
you might end up deleting your system.
How to encrypt and decrypt String with my passphrase in Java (Pc not mobile platform)?
I just want to add that if you want to somehow store the encrypted byte array as String and then retrieve it and decrypt it (often for obfuscation of database values) you can use this approach:
import java.security.Key;
import javax.crypto.Cipher;
import javax.crypto.spec.SecretKeySpec;
public class StrongAES
{
public void run()
{
try
{
String text = "Hello World";
String key = "Bar12345Bar12345"; // 128 bit key
// Create key and cipher
Key aesKey = new SecretKeySpec(key.getBytes(), "AES");
Cipher cipher = Cipher.getInstance("AES");
// encrypt the text
cipher.init(Cipher.ENCRYPT_MODE, aesKey);
byte[] encrypted = cipher.doFinal(text.getBytes());
StringBuilder sb = new StringBuilder();
for (byte b: encrypted) {
sb.append((char)b);
}
// the encrypted String
String enc = sb.toString();
System.out.println("encrypted:" + enc);
// now convert the string to byte array
// for decryption
byte[] bb = new byte[enc.length()];
for (int i=0; i<enc.length(); i++) {
bb[i] = (byte) enc.charAt(i);
}
// decrypt the text
cipher.init(Cipher.DECRYPT_MODE, aesKey);
String decrypted = new String(cipher.doFinal(bb));
System.err.println("decrypted:" + decrypted);
}
catch(Exception e)
{
e.printStackTrace();
}
}
public static void main(String[] args)
{
StrongAES app = new StrongAES();
app.run();
}
}
Finding whether a point lies inside a rectangle or not
How is the rectangle represented? Three points? Four points? Point, sides and angle? Two points and a side? Something else? Without knowing that, any attempts to answer your question will have only purely academic value.
In any case, for any convex polygon (including rectangle) the test is very simple: check each edge of the polygon, assuming each edge is oriented in counterclockwise direction, and test whether the point lies to the left of the edge (in the left-hand half-plane). If all edges pass the test - the point is inside. If at least one fails - the point is outside.
In order to test whether the point (xp, yp)
lies on the left-hand side of the edge (x1, y1) - (x2, y2)
, you just need to calculate
D = (x2 - x1) * (yp - y1) - (xp - x1) * (y2 - y1)
If D > 0
, the point is on the left-hand side. If D < 0
, the point is on the right-hand side. If D = 0
, the point is on the line.
The previous version of this answer described a seemingly different version of left-hand side test (see below). But it can be easily shown that it calculates the same value.
... In order to test whether the point (xp, yp)
lies on the left-hand side of the edge (x1, y1) - (x2, y2)
, you need to build the line equation for the line containing the edge. The equation is as follows
A * x + B * y + C = 0
where
A = -(y2 - y1)
B = x2 - x1
C = -(A * x1 + B * y1)
Now all you need to do is to calculate
D = A * xp + B * yp + C
If D > 0
, the point is on the left-hand side. If D < 0
, the point is on the right-hand side. If D = 0
, the point is on the line.
However, this test, again, works for any convex polygon, meaning that it might be too generic for a rectangle. A rectangle might allow a simpler test... For example, in a rectangle (or in any other parallelogram) the values of A
and B
have the same magnitude but different signs for opposing (i.e. parallel) edges, which can be exploited to simplify the test.
How can I get onclick event on webview in android?
I think you can also use MotionEvent.ACTION_UP state, example:
@Override
public boolean onTouch(View v, MotionEvent event) {
switch (v.getId()) {
case R.id.iv:
if (event.getAction() == MotionEvent.ACTION_UP) {
if (isheadAndFootShow == false) {
headLayout.setVisibility(View.VISIBLE);
footLayout.setVisibility(View.VISIBLE);
isheadAndFootShow = true;
} else {
headLayout.setVisibility(View.INVISIBLE);
footLayout.setVisibility(View.INVISIBLE);
isheadAndFootShow = false;
}
return true;
}
break;
}
return false;
}
Writing a Python list of lists to a csv file
Make sure to indicate lineterinator='\n'
when create the writer; otherwise, an extra empty line might be written into file after each data line when data sources are from other csv file...
Here is my solution:
with open('csvfile', 'a') as csvfile:
spamwriter = csv.writer(csvfile, delimiter=' ',quotechar='|', quoting=csv.QUOTE_MINIMAL, lineterminator='\n')
for i in range(0, len(data)):
spamwriter.writerow(data[i])
Linux command to print directory structure in the form of a tree
Is this what you're looking for tree? It should be in most distributions (maybe as an optional install).
~> tree -d /proc/self/
/proc/self/
|-- attr
|-- cwd -> /proc
|-- fd
| `-- 3 -> /proc/15589/fd
|-- fdinfo
|-- net
| |-- dev_snmp6
| |-- netfilter
| |-- rpc
| | |-- auth.rpcsec.context
| | |-- auth.rpcsec.init
| | |-- auth.unix.gid
| | |-- auth.unix.ip
| | |-- nfs4.idtoname
| | |-- nfs4.nametoid
| | |-- nfsd.export
| | `-- nfsd.fh
| `-- stat
|-- root -> /
`-- task
`-- 15589
|-- attr
|-- cwd -> /proc
|-- fd
| `-- 3 -> /proc/15589/task/15589/fd
|-- fdinfo
`-- root -> /
27 directories
sample taken from maintainer's web page.
You can add the option -L #
where #
is replaced by a number, to specify the max recursion depth.
Remove -d
to display also files.
Removing NA observations with dplyr::filter()
From @Ben Bolker:
[T]his has nothing specifically to do with dplyr::filter()
From @Marat Talipov:
[A]ny comparison with NA, including NA==NA, will return NA
From a related answer by @farnsy:
The == operator does not treat NA's as you would expect it to.
Think of NA as meaning "I don't know what's there". The correct answer
to 3 > NA is obviously NA because we don't know if the missing value
is larger than 3 or not. Well, it's the same for NA == NA. They are
both missing values but the true values could be quite different, so
the correct answer is "I don't know."
R doesn't know what you are doing in your analysis, so instead of
potentially introducing bugs that would later end up being published
an embarrassing you, it doesn't allow comparison operators to think NA
is a value.
What's the purpose of the LEA instruction?
The 8086 has a large family of instructions that accept a register operand and an effective address, perform some computations to compute the offset part of that effective address, and perform some operation involving the register and the memory referred to by the computed address. It was fairly simple to have one of the instructions in that family behave as above except for skipping that actual memory operation. Thus, the instructions:
mov ax,[bx+si+5]
lea ax,[bx+si+5]
were implemented almost identically internally. The difference is a skipped step. Both instructions work something like:
temp = fetched immediate operand (5)
temp += bx
temp += si
address_out = temp (skipped for LEA)
trigger 16-bit read (skipped for LEA)
temp = data_in (skipped for LEA)
ax = temp
As for why Intel thought this instruction was worth including, I'm not exactly sure, but the fact that it was cheap to implement would have been a big factor. Another factor would have been the fact that Intel's assembler allowed symbols to be defined relative to the BP
register. If fnord
was defined as a BP
-relative symbol (e.g. BP+8
), one could say:
mov ax,fnord ; Equivalent to "mov ax,[BP+8]"
If one wanted to use something like stosw
to store data to a BP-relative address, being able to say
mov ax,0 ; Data to store
mov cx,16 ; Number of words
lea di,fnord
rep movs fnord ; Address is ignored EXCEPT to note that it's an SS-relative word ptr
was more convenient than:
mov ax,0 ; Data to store
mov cx,16 ; Number of words
mov di,bp
add di,offset fnord (i.e. 8)
rep movs fnord ; Address is ignored EXCEPT to note that it's an SS-relative word ptr
Note that forgetting the world "offset" would cause the contents of location [BP+8]
, rather than the value 8, to be added to DI
. Oops.
Canvas width and height in HTML5
The canvas
DOM element has .height
and .width
properties that correspond to the height="…"
and width="…"
attributes. Set them to numeric values in JavaScript code to resize your canvas. For example:
var canvas = document.getElementsByTagName('canvas')[0];
canvas.width = 800;
canvas.height = 600;
Note that this clears the canvas, though you should follow with ctx.clearRect( 0, 0, ctx.canvas.width, ctx.canvas.height);
to handle those browsers that don't fully clear the canvas. You'll need to redraw of any content you wanted displayed after the size change.
Note further that the height and width are the logical canvas dimensions used for drawing and are different from the style.height
and style.width
CSS attributes. If you don't set the CSS attributes, the intrinsic size of the canvas will be used as its display size; if you do set the CSS attributes, and they differ from the canvas dimensions, your content will be scaled in the browser. For example:
// Make a canvas that has a blurry pixelated zoom-in
// with each canvas pixel drawn showing as roughly 2x2 on screen
canvas.width = 400;
canvas.height = 300;
canvas.style.width = '800px';
canvas.style.height = '600px';
See this live example of a canvas that is zoomed in by 4x.
_x000D_
_x000D_
var c = document.getElementsByTagName('canvas')[0];_x000D_
var ctx = c.getContext('2d');_x000D_
ctx.lineWidth = 1;_x000D_
ctx.strokeStyle = '#f00';_x000D_
ctx.fillStyle = '#eff';_x000D_
_x000D_
ctx.fillRect( 10.5, 10.5, 20, 20 );_x000D_
ctx.strokeRect( 10.5, 10.5, 20, 20 );_x000D_
ctx.fillRect( 40, 10.5, 20, 20 );_x000D_
ctx.strokeRect( 40, 10.5, 20, 20 );_x000D_
ctx.fillRect( 70, 10, 20, 20 );_x000D_
ctx.strokeRect( 70, 10, 20, 20 );_x000D_
_x000D_
ctx.strokeStyle = '#fff';_x000D_
ctx.strokeRect( 10.5, 10.5, 20, 20 );_x000D_
ctx.strokeRect( 40, 10.5, 20, 20 );_x000D_
ctx.strokeRect( 70, 10, 20, 20 );
_x000D_
body { background:#eee; margin:1em; text-align:center }_x000D_
canvas { background:#fff; border:1px solid #ccc; width:400px; height:160px }
_x000D_
<canvas width="100" height="40"></canvas>_x000D_
<p>Showing that re-drawing the same antialiased lines does not obliterate old antialiased lines.</p>
_x000D_
_x000D_
_x000D_
How do I add an existing Solution to GitHub from Visual Studio 2013
It's a few less clicks in VS2017, and if the local repo is ahead of the Git clone, click Source control from the pop-up project menu:
This brings up the Team Explorer Changes dialog:
Type in a description- here it's "Stack Overflow Example Commit".
Make a choice of the three options on offer, all of which are explained here.
Android Color Picker
I know the question is old, but if someone is looking for a great new android color picker that use material design I have forked an great project from github and made a simple-to-use android color picker dialog.
This is the project: Android Color Picker
Android Color Picker dialog
HOW TO USE IT
Adding the library to your project
The aar artifact is available at the jcenter repository. Declare the repository and the
dependency in your build.gradle
.
(root)
repositories {
jcenter()
}
(module)
dependencies {
compile 'com.pes.materialcolorpicker:library:1.0.2'
}
Use the library
Create a color picker dialog object
final ColorPicker cp = new ColorPicker(MainActivity.this, defaultColorR, defaultColorG, defaultColorB);
defaultColorR, defaultColorG, defaultColorB are 3 integer ( value 0-255) for the initialization of the color picker with your custom color value. If you don't want to start with a color set them to 0 or use only the first argument
Then show the dialog (when & where you want) and save the selected color
/* Show color picker dialog */
cp.show();
/* On Click listener for the dialog, when the user select the color */
Button okColor = (Button)cp.findViewById(R.id.okColorButton);
okColor.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
/* You can get single channel (value 0-255) */
selectedColorR = cp.getRed();
selectedColorG = cp.getGreen();
selectedColorB = cp.getBlue();
/* Or the android RGB Color (see the android Color class reference) */
selectedColorRGB = cp.getColor();
cp.dismiss();
}
});
That's all :)
File loading by getClass().getResource()
getClass().getResource()
uses the class loader to load the resource. This means that the resource must be in the classpath to be loaded.
When doing it with Eclipse, everything you put in the source folder is "compiled" by Eclipse:
- .java files are compiled into .class files that go the the bin directory (by default)
- other files are copied to the bin directory (respecting the package/folder hirearchy)
When launching the program with Eclipse, the bin directory is thus in the classpath, and since it contains the Test.properties file, this file can be loaded by the class loader, using getResource()
or getResourceAsStream()
.
If it doesn't work from the command line, it's thus because the file is not in the classpath.
Note that you should NOT do
FileInputStream inputStream = new FileInputStream(new File(getClass().getResource(url).toURI()));
to load a resource. Because that can work only if the file is loaded from the file system. If you package your app into a jar file, or if you load the classes over a network, it won't work. To get an InputStream, just use
getClass().getResourceAsStream("Test.properties")
And finally, as the documentation indicates,
Foo.class.getResourceAsStream("Test.properties")
will load a Test.properties file located in the same package as the class Foo.
Foo.class.getResourceAsStream("/com/foo/bar/Test.properties")
will load a Test.properties file located in the package com.foo.bar
.
What are pipe and tap methods in Angular tutorial?
You are right, the documentation lacks of those methods. However when I dug into rxjs repository, I found nice comments about tap (too long to paste here) and pipe operators:
/**
* Used to stitch together functional operators into a chain.
* @method pipe
* @return {Observable} the Observable result of all of the operators having
* been called in the order they were passed in.
*
* @example
*
* import { map, filter, scan } from 'rxjs/operators';
*
* Rx.Observable.interval(1000)
* .pipe(
* filter(x => x % 2 === 0),
* map(x => x + x),
* scan((acc, x) => acc + x)
* )
* .subscribe(x => console.log(x))
*/
In brief:
Pipe: Used to stitch together functional operators into a chain. Before we could just do observable.filter().map().scan()
, but since every RxJS operator is a standalone function rather than an Observable's method, we need pipe()
to make a chain of those operators (see example above).
Tap: Can perform side effects with observed data but does not modify the stream in any way. Formerly called do()
. You can think of it as if observable was an array over time, then tap()
would be an equivalent to Array.forEach()
.
TypeError: can't pickle _thread.lock objects
You need to change from queue import Queue
to from multiprocessing import Queue
.
The root reason is the former Queue is designed for threading module Queue while the latter is for multiprocessing.Process module.
For details, you can read some source code or contact me!
z-index not working with fixed positioning
the behaviour of fixed elements (and absolute elements) as defined in CSS Spec:
They behave as they are detached from document, and placed in the nearest fixed/absolute positioned parent. (not a word by word quote)
This makes zindex calculation a bit complicated, I solved my problem (the same situation) by dynamically creating a container in body element and moving all such elements (which are class-ed as "my-fixed-ones" inside that body-level element)
How to get city name from latitude and longitude coordinates in Google Maps?
I got new way to resolve this issue. Here I have used google http service to get total information of location based on longitude and latitude. You just need to pass latitude and longitude in url and your api key (ex : latlng=21.1497409, 79.08747970000002 & key=YOUR API KEY). Here is my get service in ExampleService
Class
getService(url) {
return this.http.get(url).map((data: any) => data.json())
}
this you can put anywhere you want and just call below service from component where you need location data
this._exampleService.getService("https://maps.googleapis.com/maps/api/geocode/json?latlng=21.1497409, 79.08747970000002&key=YOUR API KEY").subscribe(getplaceData => {
var placeDataDest: any;
placeDataDest = getplaceData;
console.log("i got place id yeee " + placeDataDest['results'][0]['place_id']);
console.log("i got place details yeee " + placeDataDest['results']);
});
similarly find city name....hope you will find this useful
Unable to load DLL (Module could not be found HRESULT: 0x8007007E)
There is one very funny thing (and has a technical relevance) which might waste your hours so thought of sharing it here -
I created a console application project ConsoleApplication1
and a class library project ClassLibrary1
.
All the code which was making the p/invoke was present in ClassLibrary1.dll
. So before debugging the application from visual studio I simply copied the C++ unmanaged assembly (myUnmanagedFunctions.dll
) into the \bin\debug\
directory of ClassLibrary1
project so that it can be loaded at run-time by the CLR.
I kept getting the
Unable to load DLL
error for hours. Later on I realized that all such unmanaged assemblies which are to be loaded need to be copied into the \bin\debug
directory of the start-up project ConsoleApplication1
which is usually a win form, console or web application.
So please be cautious the Current Directory
in the accepted answer actually means Current Directory
of main executable from where you application process is starting. Looks like an obvious thing but might not be so at times.
Lesson Learnt - Always place the unamanaged dlls in the same directory as the start-up executable to ensure that it can be found.
Wireshark vs Firebug vs Fiddler - pros and cons?
None of the above, if you are on a Mac. Use Charles Proxy. It's the best network/request information collecter that I have ever come across. You can view and edit all outgoing requests, and see the responses from those requests in several forms, depending on the type of the response. It costs 50 dollars for a license, but you can download the trial version and see what you think.
If your on Windows, then I would just stay with Fiddler.
div background color, to change onhover
simply try "hover" property of CSS. eg:
<html>
<head>
<style>
div
{
height:100px;
width:100px;
border:2px solid red;
}
div:hover
{
background-color:yellow;
}
</style>
</head>
<body>
<a href="#">
<div id="ab">
<p> hello there </p>
</div>
</a>
</body>
i hope this will help
How to call VS Code Editor from terminal / command line
Other easyway to do it on mac is :go to Command Palette[ Shift ?+ Command (?)+P] and type :Shell Command: Install 'code' command in PATH
once installed: Shell command 'code' successfully installed in PATH.
Then you can use code from the terminal as well.
INSERT SELECT statement in Oracle 11G
You don't need the 'values' clause when using a 'select' as your source.
insert into table1 (col1, col2)
select t1.col1, t2.col2 from oldtable1 t1, oldtable2 t2;
Convert HTML to NSAttributedString in iOS
In iOS 7, UIKit added an initWithData:options:documentAttributes:error:
method which can initialize an NSAttributedString
using HTML, eg:
[[NSAttributedString alloc] initWithData:[htmlString dataUsingEncoding:NSUTF8StringEncoding]
options:@{NSDocumentTypeDocumentAttribute: NSHTMLTextDocumentType,
NSCharacterEncodingDocumentAttribute: @(NSUTF8StringEncoding)}
documentAttributes:nil error:nil];
In Swift:
let htmlData = NSString(string: details).data(using: String.Encoding.unicode.rawValue)
let options = [NSAttributedString.DocumentReadingOptionKey.documentType:
NSAttributedString.DocumentType.html]
let attributedString = try? NSMutableAttributedString(data: htmlData ?? Data(),
options: options,
documentAttributes: nil)
How to clear basic authentication details in chrome
A lot of great suggestions here, I'll give the one that I found the most efficient:
Just change your password in the site. The old authentication will became outdated and Chrome will request it again.
Since I had a terminal open, I did a simple script to change the password and in two keypresses it were incremented.
Add string in a certain position in Python
If you want many inserts
from rope.base.codeanalyze import ChangeCollector
c = ChangeCollector(code)
c.add_change(5, 5, '<span style="background-color:#339999;">')
c.add_change(10, 10, '</span>')
rend_code = c.get_changed()
Auto-refreshing div with jQuery - setTimeout or another method?
Another modification:
function update() {
$.get("response.php", function(data) {
$("#some_div").html(data);
window.setTimeout(update, 10000);
});
}
The difference with this is that it waits 10 seconds AFTER the ajax call is one. So really the time between refreshes is 10 seconds + length of ajax call. The benefit of this is if your server takes longer than 10 seconds to respond, you don't get two (and eventually, many) simultaneous AJAX calls happening.
Also, if the server fails to respond, it won't keep trying.
I've used a similar method in the past using .ajax to handle even more complex behaviour:
function update() {
$("#notice_div").html('Loading..');
$.ajax({
type: 'GET',
url: 'response.php',
timeout: 2000,
success: function(data) {
$("#some_div").html(data);
$("#notice_div").html('');
window.setTimeout(update, 10000);
},
error: function (XMLHttpRequest, textStatus, errorThrown) {
$("#notice_div").html('Timeout contacting server..');
window.setTimeout(update, 60000);
}
}
This shows a loading message while loading (put an animated gif in there for typical "web 2.0" style). If the server times out (in this case takes longer than 2s) or any other kind of error happens, it shows an error, and it waits for 60 seconds before contacting the server again.
This can be especially beneficial when doing fast updates with a larger number of users, where you don't want everyone to suddenly cripple a lagging server with requests that are all just timing out anyways.
Convert a List<T> into an ObservableCollection<T>
ObservableCollection < T > has a constructor overload
which takes IEnumerable < T >
Example for a List of int
:
ObservableCollection<int> myCollection = new ObservableCollection<int>(myList);
One more example for a List of ObjectA
:
ObservableCollection<ObjectA> myCollection = new ObservableCollection<ObjectA>(myList as List<ObjectA>);
Class vs. static method in JavaScript
ES6 supports now class
& static
keywords like a charm :
class Foo {
constructor() {}
talk() {
console.log("i am not static");
}
static saying() {
console.log(this.speech);
}
static get speech() {
return "i am static method";
}
}
How to run binary file in Linux
To execute a binary or .run file in Linux from the shell, use the dot forward slash friend
./binary_file_name
and if it fails say because of permissions, you could try this before executing it
chmod +x binary_file_name
# then execute it
./binary_file_name
Hope it helps
How to install Jdk in centos
There are JDK versions available from the base CentOS repositories. Depending on your version of CentOS, and the JDK you want to install, the following as root should give you what you want:
OpenJDK Runtime Environment (Java SE 6)
yum install java-1.6.0-openjdk
OpenJDK Runtime Environment (Java SE 7)
yum install java-1.7.0-openjdk
OpenJDK Development Environment (Java SE 7)
yum install java-1.7.0-openjdk-devel
OpenJDK Development Environment (Java SE 6)
yum install java-1.6.0-openjdk-devel
Update for Java 8
In CentOS 6.6 or later, Java 8 is available. Similar to 6 and 7 above, the packages are as follows:
OpenJDK Runtime Environment (Java SE 8)
yum install java-1.8.0-openjdk
OpenJDK Development Environment (Java SE 8)
yum install java-1.8.0-openjdk-devel
There's also a 'headless' JRE package that is the same as the above JRE, except it doesn't contain audio/video support. This can be used for a slightly more minimal installation:
OpenJDK Runtime Environment - Headless (Java SE 8)
yum install java-1.8.0-openjdk-headless
How to post JSON to a server using C#?
The HttpClient
type is a newer implementation than the WebClient
and HttpWebRequest
.
You can simply use the following lines.
string myJson = "{'Username': 'myusername','Password':'pass'}";
using (var client = new HttpClient())
{
var response = await client.PostAsync(
"http://yourUrl",
new StringContent(myJson, Encoding.UTF8, "application/json"));
}
When you need your HttpClient
more than once it's recommended to only create one instance and reuse it or use the new HttpClientFactory
.
How to clear PermGen space Error in tomcat
You have to allocate more space to the PermGenSpace of the tomcat JVM.
This can be done with the JVM argument : -XX:MaxPermSize=128m
By default, the PermGen space is 64M (and it contains all compiled classes, so if you have a lot of jar (classes) in your classpath, you may indeed fill this space).
On a side note, you can monitor the size of the PermGen space with JVisualVM and you can even inspect its content with YourKit Java Profiler
How do I loop through rows with a data reader in C#?
There is no way to get "the whole row" at once - you need to loop through the rows, and for each row, you need to read each column separately:
using(SqlDataReader rdr = cmd.ExecuteReader())
{
while (rdr.Read())
{
string value1 = rdr.GetString(0);
string value2 = rdr.GetString(1);
string value3 = rdr.GetString(2);
}
}
What you do with those strings that you read for each row is entirely up to you - you could store them into a class that you've defined, or whatever....
Left align and right align within div in Bootstrap
<div class="row">
<div class="col-xs-6 col-sm-4">Total cost</div>
<div class="col-xs-6 col-sm-4"></div>
<div class="clearfix visible-xs-block"></div>
<div class="col-xs-6 col-sm-4">$42</div>
</div>
That should do the job just ok
How to make <input type="date"> supported on all browsers? Any alternatives?
<html>
<head>
<title>Date picker works for all browsers(IE, Firefox, Chrome)</title>
<script>
var datefield = document.createElement("input")
datefield.setAttribute("type", "date")
if (datefield.type != "date") { // if browser doesn't support input type="date", load files for jQuery UI Date Picker
document.write('<link href="http://ajax.googleapis.com/ajax/libs/jqueryui/1.8/themes/base/jquery-ui.css" rel="stylesheet" type="text/css" />\n')
document.write('<script src="http://ajax.googleapis.com/ajax/libs/jquery/1.4/jquery.min.js"><\/script>\n')
document.write('<script src="http://ajax.googleapis.com/ajax/libs/jqueryui/1.8/jquery-ui.min.js"><\/script>\n')
}
</script>
<script>
if (datefield.type != "date") { // if browser doesn't support input type="date", initialize date picker widget:
jQuery(function($) { // on document.ready
$('#start_date').datepicker({
dateFormat: 'yy-mm-dd'
});
$('#end_date').datepicker({
dateFormat: 'yy-mm-dd'
});
})
}
</script>
</head>
<body>
<input name="start_date" id="start_date" type="date" required>
<input name="end_date" id="end_date" required>
</body>
</html>
window.history.pushState refreshing the browser
window.history.pushState({urlPath:'/page1'},"",'/page1')
Only works after page is loaded, and when you will click on refresh it doesn't mean that there is any real URL.
What you should do here is knowing to which URL you are getting redirected when you reload this page.
And on that page you can get the conditions by getting the current URL and making all of your conditions.
How can I set the request header for curl?
To pass multiple headers in a curl request you simply add additional -H
or --header
to your curl command.
Example
//Simplified
$ curl -v -H 'header1:val' -H 'header2:val' URL
//Explanatory
$ curl -v -H 'Connection: keep-alive' -H 'Content-Type: application/json' https://www.example.com
Going Further
For standard HTTP header fields such as User-Agent, Cookie, Host, there is actually another way to setting them. The curl command offers designated options for setting these header fields:
- -A (or --user-agent): set "User-Agent" field.
- -b (or --cookie): set "Cookie" field.
- -e (or --referer): set "Referer" field.
- -H (or --header): set "Header" field
For example, the following two commands are equivalent. Both of them change "User-Agent" string in the HTTP header.
$ curl -v -H "Content-Type: application/json" -H "User-Agent: UserAgentString" https://www.example.com
$ curl -v -H "Content-Type: application/json" -A "UserAgentString" https://www.example.com
C# Iterate through Class properties
// the index of each item in fieldNames must correspond to
// the correct index in resultItems
var fieldnames = new []{"itemtype", "etc etc "};
for (int e = 0; e < fieldNames.Length - 1; e++)
{
newRecord
.GetType()
.GetProperty(fieldNames[e])
.SetValue(newRecord, resultItems[e]);
}
Entity Framework Timeouts
This is what I've fund out. Maybe it will help to someone:
So here we go:
If You use LINQ with EF looking for some exact elements contained in the list like this:
await context.MyObject1.Include("MyObject2").Where(t => IdList.Contains(t.MyObjectId)).ToListAsync();
everything is going fine until IdList contains more than one Id.
The “timeout” problem comes out if the list contains just one Id. To resolve the issue use if condition to check number of ids in IdList.
Example:
if (IdList.Count == 1)
{
result = await entities. MyObject1.Include("MyObject2").Where(t => IdList.FirstOrDefault()==t. MyObjectId).ToListAsync();
}
else
{
result = await entities. MyObject1.Include("MyObject2").Where(t => IdList.Contains(t. MyObjectId)).ToListAsync();
}
Explanation:
Simply try to use Sql Profiler and check the Select statement generated by Entity frameeork. …
How can I use different certificates on specific connections?
I've had to do something like this when using commons-httpclient to access an internal https server with a self-signed certificate. Yes, our solution was to create a custom TrustManager that simply passed everything (logging a debug message).
This comes down to having our own SSLSocketFactory that creates SSL sockets from our local SSLContext, which is set up to have only our local TrustManager associated with it. You don't need to go near a keystore/certstore at all.
So this is in our LocalSSLSocketFactory:
static {
try {
SSL_CONTEXT = SSLContext.getInstance("SSL");
SSL_CONTEXT.init(null, new TrustManager[] { new LocalSSLTrustManager() }, null);
} catch (NoSuchAlgorithmException e) {
throw new RuntimeException("Unable to initialise SSL context", e);
} catch (KeyManagementException e) {
throw new RuntimeException("Unable to initialise SSL context", e);
}
}
public Socket createSocket(String host, int port) throws IOException, UnknownHostException {
LOG.trace("createSocket(host => {}, port => {})", new Object[] { host, new Integer(port) });
return SSL_CONTEXT.getSocketFactory().createSocket(host, port);
}
Along with other methods implementing SecureProtocolSocketFactory. LocalSSLTrustManager is the aforementioned dummy trust manager implementation.
How to add image in Flutter
How to include images in your app
1. Create an assets/images
folder
- This should be located in the root of your project, in the same folder as your
pubspec.yaml
file.
- In Android Studio you can right click in the Project view
- You don't have to call it
assets
or images
. You don't even need to make images
a subfolder. Whatever name you use, though, is what you will regester in the pubspec.yaml
file.
2. Add your image to the new folder
- You can just copy your image into
assets/images
. The relative path of lake.jpg
, for example, would be assets/images/lake.jpg
.
3. Register the assets folder in pubspec.yaml
Open the pubspec.yaml
file that is in the root of your project.
Add an assets
subsection to the flutter
section like this:
flutter:
assets:
- assets/images/lake.jpg
If you have multiple images that you want to include then you can leave off the file name and just use the directory name (include the final /
):
flutter:
assets:
- assets/images/
4. Use the image in code
Get the asset in an Image widget with Image.asset('assets/images/lake.jpg')
.
The entire main.dart
file is here:
import 'package:flutter/material.dart';
void main() => runApp(MyApp());
class MyApp extends StatelessWidget {
@override
Widget build(BuildContext context) {
return MaterialApp(
home: Scaffold(
appBar: AppBar(
title: Text("Image from assets"),
),
body: Image.asset('assets/images/lake.jpg'), // <--- image
),
);
}
}
5. Restart your app
When making changes to pubspec.yaml I find that I often need to completely stop my app and restart it again, especially when adding assets. Otherwise I get a crash.
Running the app now you should have something like this:
Further reading
- See the documentation for how to do things like provide alternate images for different densities.
Videos
The first video here goes into a lot of detail about how to include images in your app. The second video covers more about how to adjust how they look.
Controlling number of decimal digits in print output in R
The reason it is only a suggestion is that you could quite easily write a print function that ignored the options value. The built-in printing and formatting functions do use the options
value as a default.
As to the second question, since R uses finite precision arithmetic, your answers aren't accurate beyond 15 or 16 decimal places, so in general, more aren't required. The gmp and rcdd packages deal with multiple precision arithmetic (via an interace to the gmp library), but this is mostly related to big integers rather than more decimal places for your doubles.
Mathematica or Maple will allow you to give as many decimal places as your heart desires.
EDIT:
It might be useful to think about the difference between decimal places and significant figures. If you are doing statistical tests that rely on differences beyond the 15th significant figure, then your analysis is almost certainly junk.
On the other hand, if you are just dealing with very small numbers, that is less of a problem, since R can handle number as small as .Machine$double.xmin
(usually 2e-308).
Compare these two analyses.
x1 <- rnorm(50, 1, 1e-15)
y1 <- rnorm(50, 1 + 1e-15, 1e-15)
t.test(x1, y1) #Should throw an error
x2 <- rnorm(50, 0, 1e-15)
y2 <- rnorm(50, 1e-15, 1e-15)
t.test(x2, y2) #ok
In the first case, differences between numbers only occur after many significant figures, so the data are "nearly constant". In the second case, Although the size of the differences between numbers are the same, compared to the magnitude of the numbers themselves they are large.
As mentioned by e3bo, you can use multiple-precision floating point numbers using the Rmpfr
package.
mpfr("3.141592653589793238462643383279502884197169399375105820974944592307816406286208998628034825")
These are slower and more memory intensive to use than regular (double precision) numeric
vectors, but can be useful if you have a poorly conditioned problem or unstable algorithm.
How to pass a URI to an intent?
In Intent, you can directly put Uri. You don't need to convert the Uri to string and convert back again to Uri.
Look at this simple approach.
// put uri to intent
intent.setData(imageUri);
And to get Uri back from intent:
// Get Uri from Intent
Uri imageUri=getIntent().getData();
jquery data selector
If you also use jQueryUI, you get a (simple) version of the :data
selector with it that checks for the presence of a data item, so you can do something like $("div:data(view)")
, or $( this ).closest(":data(view)")
.
See http://api.jqueryui.com/data-selector/ . I don't know for how long they've had it, but it's there now!
Can't specify the 'async' modifier on the 'Main' method of a console app
You can do this without needing external libraries also by doing the following:
class Program
{
static void Main(string[] args)
{
Bootstrapper bs = new Bootstrapper();
var getListTask = bs.GetList(); // returns the Task<List<TvChannel>>
Task.WaitAll(getListTask); // block while the task completes
var list = getListTask.Result;
}
}
Pair/tuple data type in Go
You could do something like this if you wanted
package main
import "fmt"
type Pair struct {
a, b interface{}
}
func main() {
p1 := Pair{"finished", 42}
p2 := Pair{6.1, "hello"}
fmt.Println("p1=", p1, "p2=", p2)
fmt.Println("p1.b", p1.b)
// But to use the values you'll need a type assertion
s := p1.a.(string) + " now"
fmt.Println("p1.a", s)
}
However I think what you have already is perfectly idiomatic and the struct describes your data perfectly which is a big advantage over using plain tuples.
Wait for Angular 2 to load/resolve model before rendering view/template
Try {{model?.person.name}}
this should wait for model to not be undefined
and then render.
Angular 2 refers to this ?.
syntax as the Elvis operator. Reference to it in the documentation is hard to find so here is a copy of it in case they change/move it:
The Elvis Operator ( ?. ) and null property paths
The Angular “Elvis” operator ( ?. ) is a fluent and convenient way to guard against null and undefined values in property paths. Here it is, protecting against a view render failure if the currentHero is null.
The current hero's name is {{currentHero?.firstName}}
Let’s elaborate on the problem and this particular solution.
What happens when the following data bound title property is null?
The title is {{ title }}
The view still renders but the displayed value is blank; we see only "The title is" with nothing after it. That is reasonable behavior. At least the app doesn't crash.
Suppose the template expression involves a property path as in this next example where we’re displaying the firstName of a null hero.
The null hero's name is {{nullHero.firstName}}
JavaScript throws a null reference error and so does Angular:
TypeError: Cannot read property 'firstName' of null in [null]
Worse, the entire view disappears.
We could claim that this is reasonable behavior if we believed that the hero property must never be null. If it must never be null and yet it is null, we've made a programming error that should be caught and fixed. Throwing an exception is the right thing to do.
On the other hand, null values in the property path may be OK from time to time, especially when we know the data will arrive eventually.
While we wait for data, the view should render without complaint and the null property path should display as blank just as the title property does.
Unfortunately, our app crashes when the currentHero is null.
We could code around that problem with NgIf
<!--No hero, div not displayed, no error -->
<div *ngIf="nullHero">The null hero's name is {{nullHero.firstName}}</div>
Or we could try to chain parts of the property path with &&, knowing that the expression bails out when it encounters the first null.
The null hero's name is {{nullHero && nullHero.firstName}}
These approaches have merit but they can be cumbersome, especially if the property path is long. Imagine guarding against a null somewhere in a long property path such as a.b.c.d.
The Angular “Elvis” operator ( ?. ) is a more fluent and convenient way to guard against nulls in property paths. The expression bails out when it hits the first null value. The display is blank but the app keeps rolling and there are no errors.
<!-- No hero, no problem! -->
The null hero's name is {{nullHero?.firstName}}
It works perfectly with long property paths too:
a?.b?.c?.d
How do I set the size of an HTML text box?
Try this code :
input[type="text"]{
padding:10px 0;}
This way it remains independent of what textsize has been set for the textbox. You are increasing the height using padding instead.
How to send custom headers with requests in Swagger UI?
For those who use NSwag and need a custom header:
app.UseSwaggerUi3(typeof(Startup).GetTypeInfo().Assembly, settings =>
{
settings.GeneratorSettings.IsAspNetCore = true;
settings.GeneratorSettings.OperationProcessors.Add(new OperationSecurityScopeProcessor("custom-auth"));
settings.GeneratorSettings.DocumentProcessors.Add(
new SecurityDefinitionAppender("custom-auth", new SwaggerSecurityScheme
{
Type = SwaggerSecuritySchemeType.ApiKey,
Name = "header-name",
Description = "header description",
In = SwaggerSecurityApiKeyLocation.Header
}));
});
}
Swagger UI will then include an Authorize button.