nginx - read custom header from upstream server

I was facing the same issue. I tried both $http_my_custom_header and $sent_http_my_custom_header but it did not work for me.

Although solved this issue by using $upstream_http_my_custom_header.

Redirecting to a certain route based on condition

I'm doing it using interceptors. I have created a library file which can be added to the index.html file. This way you'll have global error handling for your rest service calls and don't have to care about all errors individually. Further down I also pasted my basic-auth login library. There you can see that I also check for the 401 error and redirect to a different location. See lib/ea-basic-auth-login.js

lib/http-error-handling.js

/**
* @ngdoc overview
* @name http-error-handling
* @description
*
* Module that provides http error handling for apps.
*
* Usage:
* Hook the file in to your index.html: <script src="lib/http-error-handling.js"></script>
* Add <div class="messagesList" app-messages></div> to the index.html at the position you want to
* display the error messages.
*/
(function() {
'use strict';
angular.module('http-error-handling', [])
    .config(function($provide, $httpProvider, $compileProvider) {
        var elementsList = $();

        var showMessage = function(content, cl, time) {
            $('<div/>')
                .addClass(cl)
                .hide()
                .fadeIn('fast')
                .delay(time)
                .fadeOut('fast', function() { $(this).remove(); })
                .appendTo(elementsList)
                .text(content);
        };

        $httpProvider.responseInterceptors.push(function($timeout, $q) {
            return function(promise) {
                return promise.then(function(successResponse) {
                    if (successResponse.config.method.toUpperCase() != 'GET')
                        showMessage('Success', 'http-success-message', 5000);
                    return successResponse;

                }, function(errorResponse) {
                    switch (errorResponse.status) {
                        case 400:
                            showMessage(errorResponse.data.message, 'http-error-message', 6000);
                                }
                            }
                            break;
                        case 401:
                            showMessage('Wrong email or password', 'http-error-message', 6000);
                            break;
                        case 403:
                            showMessage('You don\'t have the right to do this', 'http-error-message', 6000);
                            break;
                        case 500:
                            showMessage('Server internal error: ' + errorResponse.data.message, 'http-error-message', 6000);
                            break;
                        default:
                            showMessage('Error ' + errorResponse.status + ': ' + errorResponse.data.message, 'http-error-message', 6000);
                    }
                    return $q.reject(errorResponse);
                });
            };
        });

        $compileProvider.directive('httpErrorMessages', function() {
            return {
                link: function(scope, element, attrs) {
                    elementsList.push($(element));
                }
            };
        });
    });
})();

css/http-error-handling.css

.http-error-message {
    background-color: #fbbcb1;
    border: 1px #e92d0c solid;
    font-size: 12px;
    font-family: arial;
    padding: 10px;
    width: 702px;
    margin-bottom: 1px;
}

.http-error-validation-message {
    background-color: #fbbcb1;
    border: 1px #e92d0c solid;
    font-size: 12px;
    font-family: arial;
    padding: 10px;
    width: 702px;
    margin-bottom: 1px;
}

http-success-message {
    background-color: #adfa9e;
    border: 1px #25ae09 solid;
    font-size: 12px;
    font-family: arial;
    padding: 10px;
    width: 702px;
    margin-bottom: 1px;
}

index.html

<!doctype html>
<html lang="en" ng-app="cc">
    <head>
        <meta charset="utf-8">
        <title>yourapp</title>
        <link rel="stylesheet" href="css/http-error-handling.css"/>
    </head>
    <body>

<!-- Display top tab menu -->
<ul class="menu">
  <li><a href="#/user">Users</a></li>
  <li><a href="#/vendor">Vendors</a></li>
  <li><logout-link/></li>
</ul>

<!-- Display errors -->
<div class="http-error-messages" http-error-messages></div>

<!-- Display partial pages -->
<div ng-view></div>

<!-- Include all the js files. In production use min.js should be used -->
<script src="lib/angular114/angular.js"></script>
<script src="lib/angular114/angular-resource.js"></script>
<script src="lib/http-error-handling.js"></script>
<script src="js/app.js"></script>
<script src="js/services.js"></script>
<script src="js/controllers.js"></script>
<script src="js/filters.js"></script>

lib/ea-basic-auth-login.js

Nearly same can be done for the login. Here you have the answer to the redirect ($location.path("/login")).

/**
* @ngdoc overview
* @name ea-basic-auth-login
* @description
*
* Module that provides http basic authentication for apps.
*
* Usage:
* Hook the file in to your index.html: <script src="lib/ea-basic-auth-login.js">  </script>
* Place <ea-login-form/> tag in to your html login page
* Place <ea-logout-link/> tag in to your html page where the user has to click to logout
*/
(function() {
'use strict';
angular.module('ea-basic-auth-login', ['ea-base64-login'])
    .config(['$httpProvider', function ($httpProvider) {
        var ea_basic_auth_login_interceptor = ['$location', '$q', function($location, $q) {
            function success(response) {
                return response;
            }

            function error(response) {
                if(response.status === 401) {
                    $location.path('/login');
                    return $q.reject(response);
                }
                else {
                    return $q.reject(response);
                }
            }

            return function(promise) {
                return promise.then(success, error);
            }
        }];
        $httpProvider.responseInterceptors.push(ea_basic_auth_login_interceptor);
    }])
    .controller('EALoginCtrl', ['$scope','$http','$location','EABase64Login', function($scope, $http, $location, EABase64Login) {
        $scope.login = function() {
            $http.defaults.headers.common['Authorization'] = 'Basic ' + EABase64Login.encode($scope.email + ':' + $scope.password);
            $location.path("/user");
        };

        $scope.logout = function() {
            $http.defaults.headers.common['Authorization'] = undefined;
            $location.path("/login");
        };
    }])
    .directive('eaLoginForm', [function() {
        return {
            restrict:   'E',
            template:   '<div id="ea_login_container" ng-controller="EALoginCtrl">' +
                        '<form id="ea_login_form" name="ea_login_form" novalidate>' +
                        '<input id="ea_login_email_field" class="ea_login_field" type="text" name="email" ng-model="email" placeholder="E-Mail"/>' +
                        '<br/>' +
                        '<input id="ea_login_password_field" class="ea_login_field" type="password" name="password" ng-model="password" placeholder="Password"/>' +
                        '<br/>' +
                        '<button class="ea_login_button" ng-click="login()">Login</button>' +
                        '</form>' +
                        '</div>',
            replace: true
        };
    }])
    .directive('eaLogoutLink', [function() {
        return {
            restrict: 'E',
            template: '<a id="ea-logout-link" ng-controller="EALoginCtrl" ng-click="logout()">Logout</a>',
            replace: true
        }
    }]);

angular.module('ea-base64-login', []).
    factory('EABase64Login', function() {
        var keyStr = 'ABCDEFGHIJKLMNOP' +
            'QRSTUVWXYZabcdef' +
            'ghijklmnopqrstuv' +
            'wxyz0123456789+/' +
            '=';

        return {
            encode: function (input) {
                var output = "";
                var chr1, chr2, chr3 = "";
                var enc1, enc2, enc3, enc4 = "";
                var i = 0;

                do {
                    chr1 = input.charCodeAt(i++);
                    chr2 = input.charCodeAt(i++);
                    chr3 = input.charCodeAt(i++);

                    enc1 = chr1 >> 2;
                    enc2 = ((chr1 & 3) << 4) | (chr2 >> 4);
                    enc3 = ((chr2 & 15) << 2) | (chr3 >> 6);
                    enc4 = chr3 & 63;

                    if (isNaN(chr2)) {
                        enc3 = enc4 = 64;
                    } else if (isNaN(chr3)) {
                        enc4 = 64;
                    }

                    output = output +
                        keyStr.charAt(enc1) +
                        keyStr.charAt(enc2) +
                        keyStr.charAt(enc3) +
                        keyStr.charAt(enc4);
                    chr1 = chr2 = chr3 = "";
                    enc1 = enc2 = enc3 = enc4 = "";
                } while (i < input.length);

                return output;
            },

            decode: function (input) {
                var output = "";
                var chr1, chr2, chr3 = "";
                var enc1, enc2, enc3, enc4 = "";
                var i = 0;

                // remove all characters that are not A-Z, a-z, 0-9, +, /, or =
                var base64test = /[^A-Za-z0-9\+\/\=]/g;
                if (base64test.exec(input)) {
                    alert("There were invalid base64 characters in the input text.\n" +
                        "Valid base64 characters are A-Z, a-z, 0-9, '+', '/',and '='\n" +
                        "Expect errors in decoding.");
                }
                input = input.replace(/[^A-Za-z0-9\+\/\=]/g, "");

                do {
                    enc1 = keyStr.indexOf(input.charAt(i++));
                    enc2 = keyStr.indexOf(input.charAt(i++));
                    enc3 = keyStr.indexOf(input.charAt(i++));
                    enc4 = keyStr.indexOf(input.charAt(i++));

                    chr1 = (enc1 << 2) | (enc2 >> 4);
                    chr2 = ((enc2 & 15) << 4) | (enc3 >> 2);
                    chr3 = ((enc3 & 3) << 6) | enc4;

                    output = output + String.fromCharCode(chr1);

                    if (enc3 != 64) {
                        output = output + String.fromCharCode(chr2);
                    }
                    if (enc4 != 64) {
                        output = output + String.fromCharCode(chr3);
                    }

                    chr1 = chr2 = chr3 = "";
                    enc1 = enc2 = enc3 = enc4 = "";

                } while (i < input.length);

                return output;
            }
        };
    });
})();

jQuery get content between <div> tags

Give the div a class or id and do something like this:

$("#example").get().innerHTML;

That works at the DOM level.

Bootstrap 3 Navbar with Logo

The easiest and best answer for this question is to set a max width and height depending on your logo, the image will be a max of 50px high but no longer than 200px.

<a href="index.html">
<img src="imgs/brand-w.png" style="max-height:50px;max-width:200px;">
</a>

This will vary depending on your logo size and the nav bar items you have.

Reading local text file into a JavaScript array

Using Node.js

sync mode:

var fs = require("fs");
var text = fs.readFileSync("./mytext.txt");
var textByLine = text.split("\n")

async mode:

var fs = require("fs");
fs.readFile("./mytext.txt", function(text){
    var textByLine = text.split("\n")
});

UPDATE

As of at least Node 6, readFileSync returns a Buffer, so it must first be converted to a string in order for split to work:

var text = fs.readFileSync("./mytext.txt").toString('utf-8');

var text = fs.readFileSync("./mytext.txt", "utf-8");

How to make Google Fonts work in IE?

After my investigation, I came up to this solution:

//writing the below line into the top of my style.css file
@import url('https://fonts.googleapis.com/css?family=Assistant:200,300,400,600,700,800&subset=hebrew');

MUST OBSERVE: We must need to write the font-weight correctly of this font. For example: font-weight:900; will not work as we have not included 900 like 200,300,400,600,700,800 into the URL address while importing from Google with the above link. We can add or include 900 to the above URL, but that will work only if the above Google Font has this option while embedding.

How to get the clicked link's href with jquery?

You're looking for $(this).attr("href");

How to send HTTP request in java?

Apache HttpComponents. The examples for the two modules - HttpCore and HttpClient will get you started right away.

Not that HttpUrlConnection is a bad choice, HttpComponents will abstract a lot of the tedious coding away. I would recommend this, if you really want to support a lot of HTTP servers/clients with minimum code. By the way, HttpCore could be used for applications (clients or servers) with minimum functionality, whereas HttpClient is to be used for clients that require support for multiple authentication schemes, cookie support etc.

How to easily resize/optimize an image size with iOS?

Adding to the slew of answers here, but I have gone for a solution which resizes by file size, rather than dimensions.

This will both reduce the dimensions and quality of the image until it reaches your given size.

func compressTo(toSizeInMB size: Double) -> UIImage? {
    let bytes = size * 1024 * 1024
    let sizeInBytes = Int(bytes)
    var needCompress:Bool = true
    var imgData:Data?
    var compressingValue:CGFloat = 1.0

    while (needCompress) {

        if let resizedImage = scaleImage(byMultiplicationFactorOf: compressingValue), let data: Data = UIImageJPEGRepresentation(resizedImage, compressingValue) {

            if data.count < sizeInBytes || compressingValue < 0.1 {
                needCompress = false
                imgData = data
            } else {
                compressingValue -= 0.1
            }
        }
    }

    if let data = imgData {
        print("Finished with compression value of: \(compressingValue)")
        return UIImage(data: data)
    }
    return nil
}

private func scaleImage(byMultiplicationFactorOf factor: CGFloat) -> UIImage? {
    let size = CGSize(width: self.size.width*factor, height: self.size.height*factor)
    UIGraphicsBeginImageContext(size)
    draw(in: CGRect(x: 0, y: 0, width: size.width, height: size.height))
    if let newImage: UIImage = UIGraphicsGetImageFromCurrentImageContext() {
        UIGraphicsEndImageContext()
        return newImage;
    }
    return nil
}

Credit for scaling by size answer

How to render an ASP.NET MVC view as a string?

This works for me:

public virtual string RenderView(ViewContext viewContext)
{
    var response = viewContext.HttpContext.Response;
    response.Flush();
    var oldFilter = response.Filter;
    Stream filter = null;
    try
    {
        filter = new MemoryStream();
        response.Filter = filter;
        viewContext.View.Render(viewContext, viewContext.HttpContext.Response.Output);
        response.Flush();
        filter.Position = 0;
        var reader = new StreamReader(filter, response.ContentEncoding);
        return reader.ReadToEnd();
    }
    finally
    {
        if (filter != null)
        {
            filter.Dispose();
        }
        response.Filter = oldFilter;
    }
}

Why do I always get the same sequence of random numbers with rand()?

If I remember the quote from Knuth's seminal work "The Art of Computer Programming" at the beginning of the chapter on Random Number Generation, it goes like this:

"Anyone who attempts to generate random numbers by mathematical means is, technically speaking, in a state of sin".

Simply put, the stock random number generators are algorithms, mathematical and 100% predictable. This is actually a good thing in a lot of situations, where a repeatable sequence of "random" numbers is desirable - for example for certain statistical exercises, where you don't want the "wobble" in results that truly random data introduces thanks to clustering effects.

Although grabbing bits of "random" data from the computer's hardware is a popular second alternative, it's not truly random either - although the more complex the operating environment, the more possibilities for randomness - or at least unpredictability.

Truly random data generators tend to look to outside sources. Radioactive decay is a favorite, as is the behavior of quasars. Anything whose roots are in quantum effects is effectively random - much to Einstein's annoyance.

Missing XML comment for publicly visible type or member

Jon Skeet's answer works great for when you're building with VisualStudio. However, if you're building the sln via the command line (in my case it was via Ant) then you may find that msbuild ignores the sln supression requests.

Adding this to the msbuild command line solved the problem for me:

/p:NoWarn=1591

#1142 - SELECT command denied to user ''@'localhost' for table 'pma_table_uiprefs'

On ubuntu, try dpkg-reconfigure phpmyadmin and recreate the phpmyadmin database. I installed using ansible and this was not done.

Git: copy all files in a directory from another branch

If there are no spaces in paths, and you are interested, like I was, in files of specific extension only, you can use

git checkout otherBranch -- $(git ls-tree --name-only -r otherBranch | egrep '*.java')

If greater than batch files

How to use the start command in a batch file?

An extra pair of rabbits' ears should do the trick.

start "" "C:\Program...

START regards the first quoted parameter as the window-title, unless it's the only parameter - and any switches up until the executable name are regarded as START switches.

'NoneType' object is not subscriptable?

The print() function returns None. You are trying to index None. You can not, because 'NoneType' object is not subscriptable.

Put the [0] inside the brackets. Now you're printing everything, and not just the first term.

Timeout on a function call

I have a different proposal which is a pure function (with the same API as the threading suggestion) and seems to work fine (based on suggestions on this thread)

def timeout(func, args=(), kwargs={}, timeout_duration=1, default=None):
    import signal

    class TimeoutError(Exception):
        pass

    def handler(signum, frame):
        raise TimeoutError()

    # set the timeout handler
    signal.signal(signal.SIGALRM, handler) 
    signal.alarm(timeout_duration)
    try:
        result = func(*args, **kwargs)
    except TimeoutError as exc:
        result = default
    finally:
        signal.alarm(0)

    return result

How do I pull files from remote without overwriting local files?

Well, yes, and no...

I understand that you want your local copies to "override" what's in the remote, but, oh, man, if someone has modified the files in the remote repo in some different way, and you just ignore their changes and try to "force" your own changes without even looking at possible conflicts, well, I weep for you (and your coworkers) ;-)

That said, though, it's really easy to do the "right thing..."

Step 1:

git stash

in your local repo. That will save away your local updates into the stash, then revert your modified files back to their pre-edit state.

Step 2:

git pull

to get any modified versions. Now, hopefully, that won't get any new versions of the files you're worried about. If it doesn't, then the next step will work smoothly. If it does, then you've got some work to do, and you'll be glad you did.

Step 3:

git stash pop

That will merge your modified versions that you stashed away in Step 1 with the versions you just pulled in Step 2. If everything goes smoothly, then you'll be all set!

If, on the other hand, there were real conflicts between what you pulled in Step 2 and your modifications (due to someone else editing in the interim), you'll find out and be told to resolve them. Do it.

Things will work out much better this way - it will probably keep your changes without any real work on your part, while alerting you to serious, serious issues.

Launch Failed Binary not found Eclipse for C in Windows

Count distinct value pairs in multiple columns in SQL

Having to return the count of a unique Bill of Materials (BOM) where each BOM have multiple positions, I dd something like this:

select t_item, t_pono, count(distinct ltrim(rtrim(t_item)) + cast(t_pono as varchar(3))) as [BOM Pono Count]
from BOMMaster
where t_pono = 1
group by t_item, t_pono

Given t_pono is a smallint datatype and t_item is a varchar(16) datatype

Why can't non-default arguments follow default arguments?

All required parameters must be placed before any default arguments. Simply because they are mandatory, whereas default arguments are not. Syntactically, it would be impossible for the interpreter to decide which values match which arguments if mixed modes were allowed. A SyntaxError is raised if the arguments are not given in the correct order:

Let us take a look at keyword arguments, using your function.

def fun1(a="who is you", b="True", x, y):
...     print a,b,x,y

Suppose its allowed to declare function as above, Then with the above declarations, we can make the following (regular) positional or keyword argument calls:

func1("ok a", "ok b", 1)  # Is 1 assigned to x or ?
func1(1)                  # Is 1 assigned to a or ?
func1(1, 2)               # ?

How you will suggest the assignment of variables in the function call, how default arguments are going to be used along with keyword arguments.

>>> def fun1(x, y, a="who is you", b="True"):
...     print a,b,x,y
...

Reference O'Reilly - Core-Python
Where as this function make use of the default arguments syntactically correct for above function calls. Keyword arguments calling prove useful for being able to provide for out-of-order positional arguments, but, coupled with default arguments, they can also be used to "skip over" missing arguments as well.

How to use concerns in Rails 4

This post helped me understand concerns.

# app/models/trader.rb
class Trader
  include Shared::Schedule
end

# app/models/concerns/shared/schedule.rb
module Shared::Schedule
  extend ActiveSupport::Concern
  ...
end

Getting Hour and Minute in PHP

Another way to address the timezone issue if you want to set the default timezone for the entire script to a certian timezone is to use date_default_timezone_set() then use one of the supported timezones.

Regex: Specify "space or start of string" and "space or end of string"

Here's what I would use:

 (?<!\S)stackoverflow(?!\S)

In other words, match "stackoverflow" if it's not preceded by a non-whitespace character and not followed by a non-whitespace character.

This is neater (IMO) than the "space-or-anchor" approach, and it doesn't assume the string starts and ends with word characters like the \b approach does.

What's the difference between import java.util.*; and import java.util.Date; ?

You probably have some other "Date" class imported somewhere (or you have a Date class in you package, which does not need to be imported). With "import java.util.*" you are using the "other" Date. In this case it's best to explicitly specify java.util.Date in the code.

Or better, try to avoid naming your classes "Date".

Unable to create Android Virtual Device

Simply because CPU/ABI says "No system images installed for this target". You need to install system images.

In the Android SDK Manager check that you have installed "ARM EABI v7a System Image" (for each Android version from 4.0 and on you have to install a system image to be able to run a virtual device)

In your case only ARM system image exsits (Android 4.2). If you were running an older version, Intel has provided System Images (Intel x86 ATOM). You can check on the internet to see the comparison in performance between both.

In my case (see image below) I haven't installed a System Image for Android 4.2, whereas I have installed ARM and Intel System Images for 4.1.2

As long as I don't install the 4.2 System Image I would have the same problem as you.

UPDATE : This recent article Speeding Up the Android Emaulator on Intel Architectures explains how to use/install correctly the intel system images to speed up the emulator.

EDIT/FOLLOW UP

What I show in the picture is for Android 4.2, as it was the original question, but is true for every versions of Android.

Of course (as @RedPlanet said), if you are developing for MIPS CPU devices you have to install the "MIPS System Image".

Finally, as @SeanJA said, you have to restart eclipse to see the new installed images. But for me, I always restart a software which I updated to be sure it takes into account all the modifications, and I assume it is a good practice to do so.

enter image description here

How to put a component inside another component in Angular2?

You don't put a component in directives

You register it in @NgModule declarations:

@NgModule({
  imports: [ BrowserModule ],
  declarations: [ App , MyChildComponent ],
  bootstrap: [ App ]
})

and then You just put it in the Parent's Template HTML as : <my-child></my-child>

That's it.

What is limiting the # of simultaneous connections my ASP.NET application can make to a web service?

Have you tried to set the value of the static DefaultConnectionLimit property programmatically?

Here is a good source of information about that true headache... ASP.NET Thread Usage on IIS 7.5, IIS 7.0, and IIS 6.0, with updates for framework 4.0.

What's the use of "enum" in Java?

An enumerated type is basically a data type that lets you describe each member of a type in a more readable and reliable way.

Here is a simple example to explain why:

Assuming you are writing a method that has something to do with seasons:

The int enum pattern

First, you declared some int static constants to represent each season.

public static final int SPRING = 0;
public static final int SUMMER = 1;
public static final int FALL = 2;
public static final int WINTER = 2;

Then, you declared a method to print name of the season into the console.

public void printSeason(int seasonCode) {
    String name = "";
    if (seasonCode == SPRING) {
        name = "Spring";
    }
    else if (seasonCode == SUMMER) {
        name = "Summer";
    }
    else if (seasonCode == FALL) {
        name = "Fall";
    }
    else if (seasonCode == WINTER) {
        name = "Winter";
    }
    System.out.println("It is " + name + " now!");
}

So, after that, you can print a season name like this.

printSeason(SPRING);
printSeason(WINTER);

This is a pretty common (but bad) way to do different things for different types of members in a class. However, since these code involves integers, so you can also call the method like this without any problems.

printSeason(0);
printSeason(1);

or even like this

printSeason(x - y);
printSeason(10000);

The compiler will not complain because these method calls are valid, and your printSeason method can still work.

But something is not right here. What does a season code of 10000 supposed to mean? What if x - y results in a negative number? When your method receives an input that has no meaning and is not supposed to be there, your program knows nothing about it.

You can fix this problem, for example, by adding an additional check.

...
else if (seasonCode == WINTER) {
    name = "Winter";
}
else {
    throw new IllegalArgumentException();
}
System.out.println(name);

Now the program will throw a RunTimeException when the season code is invalid. However, you still need to decide how you are going to handle the exception.

By the way, I am sure you noticed the code of FALL and WINTER are both 2, right?

You should get the idea now. This pattern is brittle. It makes you write condition checks everywhere. If you're making a game, and you want to add an extra season into your imaginary world, this pattern will make you go though all the methods that do things by season, and in most case you will forget some of them.

You might think class inheritance is a good idea for this case. But we just need some of them and no more.

That's when enum comes into play.

Use `enum` type

In Java, enum types are classes that export one instance for each enumeration constant via a public static final field.

Here you can declare four enumeration constants: SPRING, SUMMER, FALL, WINTER. Each has its own name.

public enum Season {
    SPRING("Spring"), SUMMER("Summer"), FALL("Fall"), WINTER("Winter");

    private String name;

    Season(String name) {
        this.name = name;
    }

    public String getName() {
        return name;
    }
}

Now, back to the method.

public void printSeason(Season season) {
    System.out.println("It is " + season.getName() + " now!");
}

Instead of using int, you can now use Season as input. Instead of a condition check, you can tell Season to give you its name.

This is how you use this method now:

printSeason(Season.SPRING);
printSeason(Season.WINTER);
printSeason(Season.WHATEVER); <-- compile error

You will get a compile-time error when you use an incorrect input, and you're guaranteed to get a non-null singleton reference of Season as long as the program compiles.

When we need an additional season, we simply add another constant in Season and no more.

public enum Season {
    SPRING("Spring"), SUMMER("Summer"), FALL("Fall"), WINTER("Winter"), 
    MYSEASON("My Season");

...

Whenever you need a fixed set of constants, enum can be a good choice (but not always). It's a more readable, more reliable and more powerful solution.

Sort a two dimensional array based on one column

class ArrayComparator implements Comparator<Comparable[]> {
    private final int columnToSort;
    private final boolean ascending;

    public ArrayComparator(int columnToSort, boolean ascending) {
        this.columnToSort = columnToSort;
        this.ascending = ascending;
    }

    public int compare(Comparable[] c1, Comparable[] c2) {
        int cmp = c1[columnToSort].compareTo(c2[columnToSort]);
        return ascending ? cmp : -cmp;
    }
}

This way you can handle any type of data in those arrays (as long as they're Comparable) and you can sort any column in ascending or descending order.

String[][] data = getData();
Arrays.sort(data, new ArrayComparator(0, true));

PS: make sure you check for ArrayIndexOutOfBounds and others.

EDIT: The above solution would only be helpful if you are able to actually store a java.util.Date in the first column or if your date format allows you to use plain String comparison for those values. Otherwise, you need to convert that String to a Date, and you can achieve that using a callback interface (as a general solution). Here's an enhanced version:

class ArrayComparator implements Comparator<Object[]> {
    private static Converter DEFAULT_CONVERTER = new Converter() {
        @Override
        public Comparable convert(Object o) {
            // simply assume the object is Comparable
            return (Comparable) o;
        }
    };
    private final int columnToSort;
    private final boolean ascending;
    private final Converter converter;


    public ArrayComparator(int columnToSort, boolean ascending) {
        this(columnToSort, ascending, DEFAULT_CONVERTER);
    }

    public ArrayComparator(int columnToSort, boolean ascending, Converter converter) {
        this.columnToSort = columnToSort;
        this.ascending = ascending;
        this.converter = converter;
    }

    public int compare(Object[] o1, Object[] o2) {
        Comparable c1 = converter.convert(o1[columnToSort]);
        Comparable c2 = converter.convert(o2[columnToSort]);
        int cmp = c1.compareTo(c2);
        return ascending ? cmp : -cmp;
    }

}

interface Converter {
    Comparable convert(Object o);
}

class DateConverter implements Converter {
    private static final DateFormat df = new SimpleDateFormat("yyyy.MM.dd hh:mm");

    @Override
    public Comparable convert(Object o) {
        try {
            return df.parse(o.toString());
        } catch (ParseException e) {
            throw new IllegalArgumentException(e);
        }
    }
}

And at this point, you can sort on your first column with:

Arrays.sort(data, new ArrayComparator(0, true, new DateConverter());

I skipped the checks for nulls and other error handling issues.

I agree this is starting to look like a framework already. :)

Last (hopefully) edit: I only now realize that your date format allows you to use plain String comparison. If that is the case, you don't need the "enhanced version".

Shell script to get the process ID on Linux

If you are going to use ps and grep then you should do it this way:

ps aux|grep r[u]by

Those square brackets will cause grep to skip the line for the grep command itself. So to use this in a script do:

output=`ps aux|grep r\[u\]by`
set -- $output
pid=$2
kill $pid
sleep 2
kill -9 $pid >/dev/null 2>&1

The backticks allow you to capture the output of a comand in a shell variable. The set -- parses the ps output into words, and $2 is the second word on the line which happens to be the pid. Then you send a TERM signal, wait a couple of seconds for ruby to to shut itself down, then kill it mercilessly if it still exists, but throw away any output because most of the time kill -9 will complain that the process is already dead.

I know that I have used this without the backslashes before the square brackets but just now I checked it on Ubuntu 12 and it seems to require them. This probably has something to do with bash's many options and the default config on different Linux distros. Hopefully the [ and ] will work anywhere but I no longer have access to the servers where I know that it worked without backslash so I cannot be sure.

One comment suggests grep-v and that is what I used to do, but then when I learned of the [] variant, I decided it was better to spawn one fewer process in the pipeline.

Path to MSBuild

To retrieve path of msbuild 15 (Visual Studio 2017) with batch from registry w/o additional tools:

set regKey=HKLM\SOFTWARE\WOW6432Node\Microsoft\VisualStudio\SxS\VS7
set regValue=15.0
for /f "skip=2 tokens=3,*" %%A in ('reg.exe query %regKey% /v %regValue% 2^>nul') do (
    set vs17path=%%A %%B
)
set msbuild15path = %vs17path%\MSBuild\15.0\Bin\MSBuild.exe

Better available tools:

vswhere: Locate Visual Studio 2017 and newer installations, see get msbuild15 path with batch (uses hardcoded path as my snippet above).
Visual Studio Setup PowerShell Module by using Microsoft.VisualStudio.Workload.MSBuildTools

fatal: Unable to create temporary file '/home/username/git/myrepo.git/./objects/pack/tmp_pack_XXXXXX': Permission denied

It would seem like your user doesn't have permission to write to that directory on the server. Please make sure that the permissions are correct. The user will need write permissions on that directory.

How to recover the deleted files using "rm -R" command in linux server?

since answers are disappointing I would like suggest a way in which I got deleted stuff back.

I use an ide to code and accidently I used rm -rf from terminal to remove complete folder. Thanks to ide I recoved it back by reverting the change from ide's local history.

(my ide is intelliJ but all ide's support history backup)

How to update fields in a model without creating a new record in django?

In my scenario, I want to update the status of status based on his id

student_obj = StudentStatus.objects.get(student_id=101)
student_obj.status= 'Enrolled'
student_obj.save()

Or If you want the last id from Student_Info table you can use the following.

student_obj = StudentStatus.objects.get(student_id=StudentInfo.objects.last().id)
student_obj.status= 'Enrolled'
student_obj.save()

Dynamic Height Issue for UITableView Cells (Swift)

To make autoresizing of UITableViewCell to work make sure you are doing these changes :

In Storyboard your UITableView should only contain Dynamic Prototype Cells (It shouldn't use static cells) otherwise autoresizing won't work.
In Storyboard your UITableViewCell's UILabel has configured for all 4 constraints that is top, bottom, leading and trailing constraints.
In Storyboard your UITableViewCell's UILabel's number of lines should be 0

In your UIViewController's viewDidLoad function set below UITableView Properties :

self.tableView.estimatedRowHeight = <minimum cell height> 
self.tableView.rowHeight = UITableViewAutomaticDimension

What difference is there between WebClient and HTTPWebRequest classes in .NET?

I know its too longtime to reply but just as an information purpose for future readers:

WebRequest

System.Object
    System.MarshalByRefObject
        System.Net.WebRequest

The WebRequest is an abstract base class. So you actually don't use it directly. You use it through it derived classes - HttpWebRequest and FileWebRequest.

You use Create method of WebRequest to create an instance of WebRequest. GetResponseStream returns data stream.

There are also FileWebRequest and FtpWebRequest classes that inherit from WebRequest. Normally, you would use WebRequest to, well, make a request and convert the return to either HttpWebRequest, FileWebRequest or FtpWebRequest, depend on your request. Below is an example:

Example:

var _request = (HttpWebRequest)WebRequest.Create("http://stackverflow.com");
var _response = (HttpWebResponse)_request.GetResponse();

WebClient

System.Object
        System.MarshalByRefObject
            System.ComponentModel.Component
                System.Net.WebClient

WebClient provides common operations to sending and receiving data from a resource identified by a URI. Simply, it’s a higher-level abstraction of HttpWebRequest. This ‘common operations’ is what differentiate WebClient from HttpWebRequest, as also shown in the sample below:

Example:

var _client = new WebClient();
var _stackContent = _client.DownloadString("http://stackverflow.com");

There are also DownloadData and DownloadFile operations under WebClient instance. These common operations also simplify code of what we would normally do with HttpWebRequest. Using HttpWebRequest, we have to get the response of our request, instantiate StreamReader to read the response and finally, convert the result to whatever type we expect. With WebClient, we just simply call DownloadData, DownloadFile or DownloadString.

However, keep in mind that WebClient.DownloadString doesn’t consider the encoding of the resource you requesting. So, you would probably end up receiving weird characters if you don’t specify and encoding.

NOTE: Basically "WebClient takes few lines of code as compared to Webrequest"

How to decompile an APK or DEX file on Android platform?

http://www.decompileandroid.com/

This website will decompile the code embedded in APK files and extract all the other assets in the file.

Why does LayoutInflater ignore the layout_width and layout_height layout parameters I've specified?

wanna add to main answer above
I tried to follow it but my recyclerView began to stretch every item to a screen
I had to add next line after inflating for reach to goal

itemLayoutView.setLayoutParams(new RecyclerView.LayoutParams(RecyclerView.LayoutParams.MATCH_PARENT, RecyclerView.LayoutParams.WRAP_CONTENT));

I already added these params by xml but it didnot work correctly
and with this line all is ok

How can I stage and commit all files, including newly added files, using a single command?

try using:

git add . && git commit -m "your message here"

Pointtype command for gnuplot

You first have to tell Gnuplot to use a style that uses points, e.g. with points or with linespoints. Try for example:

plot sin(x) with points

Output:

Now try:

plot sin(x) with points pointtype 5

Output:

You may also want to look at the output from the test command which shows you the capabilities of the current terminal. Here are the capabilities for my pngairo terminal:

What is HEAD in Git?

A branch is actually a pointer that holds a commit ID such as 17a5. HEAD is a pointer to a branch the user is currently working on.

HEAD has a reference filw which looks like this:

ref:

You can check these files by accessing .git/HEAD .git/refs that are in the repository you are working in.

why I can't get value of label with jquery and javascript?

You need text() or html() for label not val() The function should not be called for label instead it is used to get values of input like text or checkbox etc.

Change

value = $("#telefon").val();

value = $("#telefon").text();

Reading a json file in Android

Put that file in assets.

For project created in Android Studio project you need to create assets folder under the main folder.

Read that file as:

public String loadJSONFromAsset(Context context) {
        String json = null;
        try {
            InputStream is = context.getAssets().open("file_name.json");

            int size = is.available();

            byte[] buffer = new byte[size];

            is.read(buffer);

            is.close();

            json = new String(buffer, "UTF-8");


        } catch (IOException ex) {
            ex.printStackTrace();
            return null;
        }
        return json;

    }

and then you can simply read this string return by this function as

JSONObject obj = new JSONObject(json_return_by_the_function);

For further details regarding JSON see http://www.vogella.com/articles/AndroidJSON/article.html

Hope you will get what you want.

convert string date to java.sql.Date

worked for me too:

SimpleDateFormat sdf = new SimpleDateFormat("dd/MM/yyyy");
    Date parsed = null;
    try {
        parsed = sdf.parse("02/01/2014");
    } catch (ParseException e1) {
        // TODO Auto-generated catch block
        e1.printStackTrace();
    }
    java.sql.Date data = new java.sql.Date(parsed.getTime());
    contato.setDataNascimento( data);

    // Contato DataNascimento era Calendar
    //contato.setDataNascimento(Calendar.getInstance());         

    // grave nessa conexão!!! 
    ContatoDao dao = new ContatoDao("mysql");           

    // método elegante 
    dao.adiciona(contato); 
    System.out.println("Banco: ["+dao.getNome()+"] Gravado! Data: "+contato.getDataNascimento());

Assign a class name to <img> tag instead of write it in css file?

The short answer is adding a class directly to the element you want to style is indeed the most efficient way to target and style that Element. BUT, in real world scenarios it is so negligible that it is not an issue at all to worry about.

To quote Steve Ouders (CSS optimization expert) http://www.stevesouders.com/blog/2009/03/10/performance-impact-of-css-selectors/:

Based on tests I have the following hypothesis: For most web sites, the possible performance gains from optimizing CSS selectors will be small, and are not worth the costs.

Maintainability of code is much more important in real world scenarios. Since the underlying topic here is front-end performance; the real performance boosters for speedy page rendering are found in:

Make fewer HTTP requests
Use a CDN
Add an Expires header
Gzip components
Put stylesheets at the top
Put scripts at the bottom
Avoid CSS expressions
Make JS and CSS external
Reduce DNS lookups
Minify JS
Avoid redirects
Remove duplicate scripts
Configure ETags
Make AJAX cacheable

Source: http://stevesouders.com/docs/web20expo-20090402.ppt

So just to confirm, the answer is yes, example below is indeed faster but be aware of the bigger picture:

<div class="column">
   <img class="custom-style" alt="appropriate alt text" />
</div>

Django URL Redirect

The other methods work fine, but you can also use the good old django.shortcut.redirect.

The code below was taken from this answer.

In Django 2.x:

from django.shortcuts import redirect
from django.urls import path, include

urlpatterns = [
    # this example uses named URL 'hola-home' from app named hola
    # for more redirect's usage options: https://docs.djangoproject.com/en/2.1/topics/http/shortcuts/
    path('', lambda request: redirect('hola/', permanent=True)),
    path('hola/', include('hola.urls')),
]

Getting the parameters of a running JVM

You can use the JConsole command (or any other JMX client) to access that information.

Rerouting stdin and stdout from C

The os function dup2() should provide what you need (if not references to exactly what you need).

More specifically, you can dup2() the stdin file descriptor to another file descriptor, do other stuff with stdin, and then copy it back when you want.

The dup() function duplicates an open file descriptor. Specifically, it provides an alternate interface to the service provided by the fcntl() function using the F_DUPFD constant command value, with 0 for its third argument. The duplicated file descriptor shares any locks with the original.

On success, dup() returns a new file descriptor that has the following in common with the original:

Same open file (or pipe)

Same file pointer (both file descriptors share one file pointer)

Same access mode (read, write, or read/write)

How to compile LEX/YACC files on Windows?

What you (probably want) are Flex 2.5.4 (some people are now "maintaining" it and producing newer versions, but IMO they've done more to screw it up than fix any real shortcomings) and byacc 1.9 (likewise). (Edit 2017-11-17: Flex 2.5.4 is not available on Sourceforge any more, and the Flex github repository only goes back to 2.5.5. But you can apparently still get it from a Gnu ftp server at ftp://ftp.gnu.org/old-gnu/gnu-0.2/src/flex-2.5.4.tar.gz.)

Since it'll inevitably be recommended, I'll warn against using Bison. Bison was originally written by Robert Corbett, the same guy who later wrote Byacc, and he openly states that at the time he didn't really know or understand what he was doing. Unfortunately, being young and foolish, he released it under the GPL and now the GPL fans push it as the answer to life's ills even though its own author basically says it should be thought of as essentially a beta test product -- but by the convoluted reasoning of GPL fans, byacc's license doesn't have enough restrictions to qualify as "free"!

SQL - ORDER BY 'datetime' DESC

use single quotes for strings
do NOT put single quotes around table names(use ` instead)
do NOT put single quotes around numbers (you can, but it's harder to read)
do NOT put AND between ORDER BY and LIMIT
do NOT put = between ORDER BY, LIMIT keywords and condition

So you query will look like:

SELECT post_datetime 
FROM post 
WHERE type = 'published' 
ORDER BY post_datetime DESC 
LIMIT 3

How can I regenerate ios folder in React Native project?

As @Alok mentioned in the comments, you can do react-native eject to generate the ios and android folders. But you will need an app.json in your project first.

{"name": "example", "displayName": "Example"}

Convert string to datetime

well, thought I should mention a solution I came across through some trying. Discovered whilst fixing a defect of someone comparing dates as strings.

new Date(Date.parse('01-01-1970 01:03:44'))

SQL - HAVING vs. WHERE

You can not use where clause with aggregate functions because where fetch records on the basis of condition, it goes into table record by record and then fetch record on the basis of condition we have give. So that time we can not where clause. While having clause works on the resultSet which we finally get after running a query.

Example query:

select empName, sum(Bonus) 
from employees 
order by empName 
having sum(Bonus) > 5000;

This will store the resultSet in a temporary memory, then having clause will perform its work. So we can easily use aggregate functions here.

Set focus to field in dynamically loaded DIV

Yes, this happens when manipulating an element which doesn't exist yet (a few contributors here also made a good point with the unique ID). I ran into a similar issue. I also need to pass an argument to the function manipulating the element soon to be rendered.

The solution checked off here didn't help me. Finally I found one that worked right out of the box. And it's very pretty, too - a callback.

Instead of:

$( '#header' ).focus();
or the tempting:
setTimeout( $( '#header' ).focus(), 500 );

Try this:

setTimeout( function() { $( '#header' ).focus() }, 500 );

In my code, testing passing the argument, this didn't work, the timeout was ignored:

setTimeout( alert( 'Hello, '+name ), 1000 );

This works, the timeout ticks:

setTimeout( function() { alert( 'Hello, '+name ) }, 1000 );

It sucks that w3schools doesn't mention it.

Credits go to: makemineatriple.com.

Hopefully, this helps somebody who comes here.

How to read and write excel file

You can also consider JExcelApi. I find it better designed than POI. There's a tutorial here.

Oracle: what is the situation to use RAISE_APPLICATION_ERROR?

You use RAISE_APPLICATION_ERROR in order to create an Oracle style exception/error that is specific to your code/needs. Good use of these help to produce code that is clearer, more maintainable, and easier to debug.

For example, if I have an application calling a stored procedure that adds a user and that user already exists, you'll usually get back an error like:

ORA-00001: unique constraint (USERS.PK_USER_KEY) violated

Obviously this error and associated message are not unique to the task you were trying to do. Creating your own Oracle application errors allow you to be clearer on the intent of the action and the cause of the issue.

raise_application_error(-20101, 'User ' || in_user || ' already exists!');

Now your application code can write an exception handler in order to process this specific error condition. Think of it as a way to make Oracle communicate error conditions that your application expects in a "language" (for lack of a better term) that you have defined and is more meaningful to your application's problem domain.

Note that user defined errors must be in the range between -20000 and -20999.

The following link provides lots of good information on this topic and Oracle exceptions in general.

QUERY syntax using cell reference

I found out that single quote > double quote > wrapped in ampersands did work. So, for me it looks like this:

=QUERY('Youth Conference Registration'!C:Y,"select C where Y = '"&A1&"'", 0)

Difference between webdriver.get() and webdriver.navigate()

There are some differences between webdriver.get() and webdriver.navigate() method.

get()

As per the API Docs get() method in the WebDriver interface extends the SearchContext and is defined as:

/**
 * Load a new web page in the current browser window. This is done using an HTTP POST operation,
 * and the method will block until the load is complete.
 * This will follow redirects issued either by the server or as a meta-redirect from within the
 * returned HTML.
 * Synonym for {@link org.openqa.selenium.WebDriver.Navigation#to(String)}.
 */
void get(String url);

Usage:
```
driver.get("https://www.google.com/");
```

navigate()

On the other hand, navigate() is the abstraction which allows the WebDriver instance i.e. the driver to access the browser's history as well as to navigate to a given URL. The methods along with the usage are as follows:

to(java.lang.String url): Load a new web page in the current browser window.
```
driver.navigate().to("https://www.google.com/");
```
to(java.net.URL url): Overloaded version of to(String) that makes it easy to pass in a URL.
refresh(): Refresh the current page.
```
driver.navigate().refresh();
```
back(): Move back a single "item" in the browser's history.
```
driver.navigate().back();
```
forward(): Move a single "item" forward in the browser's history.
```
driver.navigate().forward();
```

How do I get the XML root node with C#?

XmlDocument xmlDoc = new XmlDocument();
xmlDoc.Load(response.GetResponseStream());
string rootNode = XmlDoc.ChildNodes[0].Name;

What is the facade design pattern?

The facade pattern is a wrapper of many other interfaces in a result to produce a simpler interface.

Design patterns are useful as they solve recurring problems and in general simplify code. In a team of developers who agree to use the same patterns it improves efficiency and understanding when maintaining each others code.

Try reading about more patterns:

Facade Pattern: http://www.dofactory.com/Patterns/PatternFacade.aspx#_self1

or more generally: http://www.dofactory.com/Patterns/Patterns.aspx

How to reload a page using Angularjs?

You need $route defined in your module and change the JS to this.

$scope.backLinkClick = function () {
  window.location.reload(); 
};

that works fine for me.

Ruby on Rails: Where to define global constants?

If your model is really "responsible" for the constants you should stick them there. You can create class methods to access them without creating a new object instance:

class Card < ActiveRecord::Base
  def self.colours
    ['white', 'blue']
  end
end

# accessible like this
Card.colours

Alternatively, you can create class variables and an accessor. This is however discouraged as class variables might act kind of surprising with inheritance and in multi-thread environments.

class Card < ActiveRecord::Base
  @@colours = ['white', 'blue'].freeze
  cattr_reader :colours
end

# accessible the same as above
Card.colours

The two options above allow you to change the returned array on each invocation of the accessor method if required. If you have true a truly unchangeable constant, you can also define it on the model class:

class Card < ActiveRecord::Base
  COLOURS = ['white', 'blue'].freeze
end

# accessible as
Card::COLOURS

You could also create global constants which are accessible from everywhere in an initializer like in the following example. This is probably the best place, if your colours are really global and used in more than one model context.

# put this into config/initializers/my_constants.rb
COLOURS = ['white', 'blue'].freeze

# accessible as a top-level constant this time
COLOURS

Note: when we define constants above, often we want to freeze the array. That prevents other code from later (inadvertently) modifying the array by e.g. adding a new element. Once an object is frozen, it can't be changed anymore.

Equivalent of waitForVisible/waitForElementPresent in Selenium WebDriver tests using Java?

Implicit and Explicit Waits

Implicit Wait

An implicit wait is to tell WebDriver to poll the DOM for a certain amount of time when trying to find an element or elements if they are not immediately available. The default setting is 0. Once set, the implicit wait is set for the life of the WebDriver object instance.

driver.manage().timeouts().implicitlyWait(10, TimeUnit.SECONDS);

Explicit Wait + Expected Conditions

An explicit waits is code you define to wait for a certain condition to occur before proceeding further in the code. The worst case of this is Thread.sleep(), which sets the condition to an exact time period to wait. There are some convenience methods provided that help you write code that will wait only as long as required. WebDriverWait in combination with ExpectedCondition is one way this can be accomplished.

WebDriverWait wait = new WebDriverWait(driver, 10);
WebElement element = wait.until(
        ExpectedConditions.visibilityOfElementLocated(By.id("someid")));

How to convert a set to a list in python?

I'm not sure that you're creating a set with this ([1, 2]) syntax, rather a list. To create a set, you should use set([1, 2]).

These brackets are just envelopping your expression, as if you would have written:

if (condition1
    and condition2 == 3):
    print something

There're not really ignored, but do nothing to your expression.

Note: (something, something_else) will create a tuple (but still no list).

A completely free agile software process tool

You can check out https://kanbanflow.com It's free for now because it's in beta and they say there is no time limit. It behaves very similar to AgileZen

I second the google doc, or you could use an online collaborative board that multiple people can edit.

Or you can host a more robust excel doc in skydrive from MS. I haven't tried that yet.

Mura.ly is another one that I am playing with currently. It has unlimited collaborators, though I think you would probably have to invite them everytime?? with a free account.

Hope that helps!

How to filter a dictionary according to an arbitrary condition function?

points_small = dict(filter(lambda (a,(b,c)): b<5 and c < 5, points.items()))

What are some ways of accessing Microsoft SQL Server from Linux?

There is a nice CLI based tool for accessing MSSQL databases now.

It's called mssql-cli and it's a bit similar to postgres' psql.

Gihub repository page

Install for example via pip (global installation, for a local one omit the sudo part):

sudo pip install mssql-cli

How to write connection string in web.config file and read from it?

try this

var configuration = WebConfigurationManager.OpenWebConfiguration("~");
var section = (ConnectionStringsSection)configuration.GetSection("connectionStrings");
section.ConnectionStrings["MyConnectionString"].ConnectionString = "Data Source=...";
configuration.Save();

Defining static const integer members in class definition

My understanding is that C++ allows static const members to be defined inside a class so long as it's an integer type.

You are sort of correct. You are allowed to initialize static const integrals in the class declaration but that is not a definition.

http://publib.boulder.ibm.com/infocenter/comphelp/v8v101/index.jsp?topic=/com.ibm.xlcpp8a.doc/language/ref/cplr038.htm

Interestingly, if I comment out the call to std::min, the code compiles and links just fine (even though test::N is also referenced on the previous line).

Any idea as to what's going on?

std::min takes its parameters by const reference. If it took them by value you'd not have this problem but since you need a reference you also need a definition.

Here's chapter/verse:

9.4.2/4 - If a static data member is of const integral or const enumeration type, its declaration in the class definition can specify a constant-initializer which shall be an integral constant expression (5.19). In that case, the member can appear in integral constant expressions. The member shall still be defined in a namespace scope if it is used in the program and the namespace scope definition shall not contain an initializer.

See Chu's answer for a possible workaround.

How to Edit a row in the datatable

Try the SetField method:

By passing column object :

table.Rows[rowIndex].SetField(column, value);

By Passing column index :

table.Rows[rowIndex].SetField(0 /*column index*/, value);

By Passing column name as string :

table.Rows[rowIndex].SetField("product_name" /*columnName*/, value);

How to debug Spring Boot application with Eclipse?

How to debug a remote staging or production Spring Boot application

Server-side

Let's assume you have successfully followed Spring Boot's guide on setting up your Spring Boot application as a service. Your application artifact resides in /srv/my-app/my-app.war, accompanied by a configuration file /srv/my-app/my-app.conf:

# This is file my-app.conf
# What can you do in this .conf file? The my-app.war is prepended with a SysV init.d script
# (yes, take a look into the war file with a text editor). As my-app.war is symlinked in the init.d directory, that init.d script
# gets executed. One of its step is actually `source`ing this .conf file. Therefore we can do anything in this .conf file that
# we can also do in a regular shell script.

JAVA_OPTS="-agentlib:jdwp=transport=dt_socket,address=localhost:8002,server=y,suspend=n"
export SPRING_PROFILES_ACTIVE=staging

When you restart your Spring Boot application with sudo service my-app restart, then in its log file located at /var/log/my-app.log should be a line saying Listening for transport dt_socket at address: 8002.

Client-side (developer machine)

Open an SSH port-forwarding tunnel to the server: ssh -L 8002:localhost:8002 [email protected]. Keep this SSH session running.

In Eclipse, from the toolbar, select Run -> Debug Configurations -> select Remote Java Application -> click the New button -> select as Connection Type Standard (Socket Attach), as Host localhost, and as Port 8002 (or whatever you have configured in the steps before). Click Apply and then Debug.

The Eclipse debugger should now connect to the remote server. Switching to the Debug perspective should show the connected JVM and its threads. Breakpoints should fire as soon as they are remotely triggered.

Automatically set appsettings.json for dev and release environments in asp.net core?

You can make use of environment variables and the ConfigurationBuilder class in your Startup constructor like this:

public Startup(IHostingEnvironment env)
{
    var builder = new ConfigurationBuilder()
    .SetBasePath(env.ContentRootPath)
    .AddJsonFile("appsettings.json", optional: true, reloadOnChange: true)
    .AddJsonFile($"appsettings.{env.EnvironmentName}.json", optional: true)
    .AddEnvironmentVariables();
    this.configuration = builder.Build();
}

Then you create an appsettings.xxx.json file for every environment you need, with "xxx" being the environment name. Note that you can put all global configuration values in your "normal" appsettings.json file and only put the environment specific stuff into these new files.

Now you only need an environment variable called ASPNETCORE_ENVIRONMENT with some specific environment value ("live", "staging", "production", whatever). You can specify this variable in your project settings for your development environment, and of course you need to set it in your staging and production environments also. The way you do it there depends on what kind of environment this is.

UPDATE: I just realized you want to choose the appsettings.xxx.json based on your current build configuration. This cannot be achieved with my proposed solution and I don't know if there is a way to do this. The "environment variable" way, however, works and might as well be a good alternative to your approach.

jQuery attr() change img src

Function imageMorph will create a new img element therefore the id is removed. Changed to

$("#wrapper > img")
You should use live() function for click event if you want you rocket lanch again.

Updated demo: http://jsfiddle.net/ynhat/QQRsW/4/

Return the most recent record from ElasticSearch index

the _timestamp didn't work out for me,

this query does work for me:

(as in mconlin's answer)

{
  "query": {
    "match_all": {}
  },
  "size": "1",
  "sort": [
    {
      "@timestamp": {
        "order": "desc"
      }
    }
  ]
}

Could be trivial but the _timestamp answer didn't gave an error but not a good result either...

Hope to help someone...

(kibana/elastic 5.0.4)

6 digits regular expression

^[0-9]{1,6}$ should do it. I don't know VB.NET good enough to know if it's the same there.

For examples, have a look at the Wikipedia.

Best practice when adding whitespace in JSX

use {} or {``} or   to create space between span element and content.

<b> {notif.name} </b> <span id="value"> &nbsp;{ notif.count }{``} </span>

Scraping data from website using vba

I modified some thing that were poping up error for me and end up with this which worked great to extract the data as I needed:

Sub get_data_web()

Dim appIE As Object
Set appIE = CreateObject("internetexplorer.application")

With appIE
    .navigate "https://finance.yahoo.com/quote/NQ%3DF/futures?p=NQ%3DF"
    .Visible = True
End With

Do While appIE.Busy
    DoEvents
Loop

Set allRowofData = appIE.document.getElementsByClassName("Ta(end) BdT Bdc($c-fuji-grey-c) H(36px)")

Dim i As Long
Dim myValue As String

Count = 1

    For Each itm In allRowofData

        For i = 0 To 4

        myValue = itm.Cells(i).innerText
        ActiveSheet.Cells(Count, i + 1).Value = myValue

        Next

        Count = Count + 1

    Next

appIE.Quit
Set appIE = Nothing


End Sub

CodeIgniter: How To Do a Select (Distinct Fieldname) MySQL Query

try it out with the following code

function fun1()  
{  
   $this->db->select('count(DISTINCT(accessid))');  
   $this->db->from('accesslog');  
   $this->db->where('record =','123');  
   $query=$this->db->get();  
   return $query->num_rows();  
}

The point of test %eax %eax

This checks if EAX is zero. The instruction test does bitwise AND between the arguments, and if EAX contains zero, the result sets the ZF, or ZeroFlag.

What is better, adjacency lists or adjacency matrices for graph problems in C++?

This answer is not just for C++ since everything mentioned is about the data structures themselves, regardless of language. And, my answer is assuming that you know the basic structure of adjacency lists and matrices.

Memory

If memory is your primary concern you can follow this formula for a simple graph that allows loops:

An adjacency matrix occupies n²/8 byte space (one bit per entry).

An adjacency list occupies 8e space, where e is the number of edges (32bit computer).

If we define the density of the graph as d = e/n² (number of edges divided by the maximum number of edges), we can find the "breakpoint" where a list takes up more memory than a matrix:

8e > n²/8 when d > 1/64

So with these numbers (still 32-bit specific) the breakpoint lands at 1/64. If the density (e/n²) is bigger than 1/64, then a matrix is preferable if you want to save memory.

You can read about this at wikipedia (article on adjacency matrices) and a lot of other sites.

Side note: One can improve the space-efficiency of the adjacency matrix by using a hash table where the keys are pairs of vertices (undirected only).

Iteration and lookup

Adjacency lists are a compact way of representing only existing edges. However, this comes at the cost of possibly slow lookup of specific edges. Since each list is as long as the degree of a vertex the worst case lookup time of checking for a specific edge can become O(n), if the list is unordered. However, looking up the neighbours of a vertex becomes trivial, and for a sparse or small graph the cost of iterating through the adjacency lists might be negligible.

Adjacency matrices on the other hand use more space in order to provide constant lookup time. Since every possible entry exists you can check for the existence of an edge in constant time using indexes. However, neighbour lookup takes O(n) since you need to check all possible neighbours. The obvious space drawback is that for sparse graphs a lot of padding is added. See the memory discussion above for more information on this.

If you're still unsure what to use: Most real-world problems produce sparse and/or large graphs, which are better suited for adjacency list representations. They might seem harder to implement but I assure you they aren't, and when you write a BFS or DFS and want to fetch all neighbours of a node they're just one line of code away. However, note that I'm not promoting adjacency lists in general.

In a simple to understand explanation, what is Runnable in Java?

Runnable is an interface defined as so:

interface Runnable {
    public void run();
}

To make a class which uses it, just define the class as (public) class MyRunnable implements Runnable {

It can be used without even making a new Thread. It's basically your basic interface with a single method, run, that can be called.

If you make a new Thread with runnable as it's parameter, it will call the run method in a new Thread.

It should also be noted that Threads implement Runnable, and that is called when the new Thread is made (in the new thread). The default implementation just calls whatever Runnable you handed in the constructor, which is why you can just do new Thread(someRunnable) without overriding Thread's run method.

How do I get and set Environment variables in C#?

Environment.SetEnvironmentVariable("Variable name", value, EnvironmentVariableTarget.User);

How to reset Django admin password?

Just type this command in your command line:

python manage.py changepassword yourusername

Print series of prime numbers in python

Here's a simple and intuitive version of checking whether it's a prime in a RECURSIVE function! :) (I did it as a homework assignment for an MIT class) In python it runs very fast until 1900. IF you try more than 1900, you'll get an interesting error :) (Would u like to check how many numbers your computer can manage?)

def is_prime(n, div=2):

    if div> n/2.0: return True

    if n% div == 0:
        return False
    else:
        div+=1
        return is_prime(n,div)

#The program:
until = 1000
for i in range(until):
    if is_prime(i):
        print i

Of course... if you like recursive functions, this small code can be upgraded with a dictionary to seriously increase its performance, and avoid that funny error. Here's a simple Level 1 upgrade with a MEMORY integration:

import datetime
def is_prime(n, div=2):
    global primelist
    if div> n/2.0: return True
    if div < primelist[0]:
        div = primelist[0]
        for x in primelist:
            if x ==0 or x==1: continue
            if n % x == 0:
                return False
    if n% div == 0:
        return False
    else:
        div+=1
        return is_prime(n,div)


now = datetime.datetime.now()
print 'time and date:',now
until = 100000
primelist=[]
for i in range(until):
    if is_prime(i):
        primelist.insert(0,i)
print "There are", len(primelist),"prime numbers, until", until
print primelist[0:100], "..."

finish = datetime.datetime.now()
print "It took your computer", finish - now , " to calculate it"

Here are the resuls, where I printed the last 100 prime numbers found.

time and date: 2013-10-15 13:32:11.674448

There are 9594 prime numbers, until 100000

[99991, 99989, 99971, 99961, 99929, 99923, 99907, 99901, 99881, 99877, 99871, 99859, 99839, 99833, 99829, 99823, 99817, 99809, 99793, 99787, 99767, 99761, 99733, 99721, 99719, 99713, 99709, 99707, 99689, 99679, 99667, 99661, 99643, 99623, 99611, 99607, 99581, 99577, 99571, 99563, 99559, 99551, 99529, 99527, 99523, 99497, 99487, 99469, 99439, 99431, 99409, 99401, 99397, 99391, 99377, 99371, 99367, 99349, 99347, 99317, 99289, 99277, 99259, 99257, 99251, 99241, 99233, 99223, 99191, 99181, 99173, 99149, 99139, 99137, 99133, 99131, 99119, 99109, 99103, 99089, 99083, 99079, 99053, 99041, 99023, 99017, 99013, 98999, 98993, 98981, 98963, 98953, 98947, 98939, 98929, 98927, 98911, 98909, 98899, 98897] ...

It took your computer 0:00:40.871083 to calculate it

So It took 40 seconds for my i7 laptop to calculate it. :)

Copy values from one column to another in the same table

try following:

UPDATE `list` SET `test` = `number`

it creates copy of all values from "number" and paste it to "test"

What are the uses of the exec command in shell scripts?

The exec built-in command mirrors functions in the kernel, there are a family of them based on execve, which is usually called from C.

exec replaces the current program in the current process, without forking a new process. It is not something you would use in every script you write, but it comes in handy on occasion. Here are some scenarios I have used it;

We want the user to run a specific application program without access to the shell. We could change the sign-in program in /etc/passwd, but maybe we want environment setting to be used from start-up files. So, in (say) .profile, the last statement says something like:
```
 exec appln-program
```
so now there is no shell to go back to. Even if appln-program crashes, the end-user cannot get to a shell, because it is not there - the exec replaced it.
We want to use a different shell to the one in /etc/passwd. Stupid as it may seem, some sites do not allow users to alter their sign-in shell. One site I know had everyone start with csh, and everyone just put into their .login (csh start-up file) a call to ksh. While that worked, it left a stray csh process running, and the logout was two stage which could get confusing. So we changed it to exec ksh which just replaced the c-shell program with the korn shell, and made everything simpler (there are other issues with this, such as the fact that the ksh is not a login-shell).
Just to save processes. If we call prog1 -> prog2 -> prog3 -> prog4 etc. and never go back, then make each call an exec. It saves resources (not much, admittedly, unless repeated) and makes shutdown simplier.

You have obviously seen exec used somewhere, perhaps if you showed the code that's bugging you we could justify its use.

Edit: I realised that my answer above is incomplete. There are two uses of exec in shells like ksh and bash - used for opening file descriptors. Here are some examples:

exec 3< thisfile          # open "thisfile" for reading on file descriptor 3
exec 4> thatfile          # open "thatfile" for writing on file descriptor 4
exec 8<> tother           # open "tother" for reading and writing on fd 8
exec 6>> other            # open "other" for appending on file descriptor 6
exec 5<&0                 # copy read file descriptor 0 onto file descriptor 5
exec 7>&4                 # copy write file descriptor 4 onto 7
exec 3<&-                 # close the read file descriptor 3
exec 6>&-                 # close the write file descriptor 6

Note that spacing is very important here. If you place a space between the fd number and the redirection symbol then exec reverts to the original meaning:

  exec 3 < thisfile       # oops, overwrite the current program with command "3"

There are several ways you can use these, on ksh use read -u or print -u, on bash, for example:

read <&3
echo stuff >&4

How to reset the use/password of jenkins on windows?

Read Initial password :

C:\Program Files(x86)\Jenkins\secrets\initialAdminPassword

Default username is 'admin' and the password is the one from initialAdminPassword when you follow the above path.

'Manage Jenkins' --> 'Manage Users' --> Password

Then logout and login to make sure new password works.

Iterating through a golang map

You could just write it out in multiline like this,

$ cat dict.go
package main

import "fmt"

func main() {
        items := map[string]interface{}{
                "foo": map[string]int{
                        "strength": 10,
                        "age": 2000,
                },
                "bar": map[string]int{
                        "strength": 20,
                        "age": 1000,
                },
        }
        for key, value := range items {
                fmt.Println("[", key, "] has items:")
                for k,v := range value.(map[string]int) {
                        fmt.Println("\t-->", k, ":", v)
                }

        }
}

And the output:

$ go run dict.go
[ foo ] has items:
        --> strength : 10
        --> age : 2000
[ bar ] has items:
        --> strength : 20
        --> age : 1000

"static const" vs "#define" vs "enum"

Another drawback of const in C is that you can't use the value in initializing another const.

static int const NUMBER_OF_FINGERS_PER_HAND = 5;
static int const NUMBER_OF_HANDS = 2;

// initializer element is not constant, this does not work.
static int const NUMBER_OF_FINGERS = NUMBER_OF_FINGERS_PER_HAND 
                                     * NUMBER_OF_HANDS;

Even this does not work with a const since the compiler does not see it as a constant:

static uint8_t const ARRAY_SIZE = 16;
static int8_t const lookup_table[ARRAY_SIZE] = {
    1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16}; // ARRAY_SIZE not a constant!

I'd be happy to use typed const in these cases, otherwise...

Understanding Apache's access log

I also don't under stand what the "-" means after the 200 140 section of the log

That value corresponds to the referer as described by Joachim. If you see a dash though, that means that there was no referer value to begin with (eg. the user went straight to a specific destination, like if he/she typed a URL in their browser)

JQuery - File attributes

<form id = "uploadForm" name = "uploadForm" enctype="multipart/form-data">
    <label for="uploadFile">Upload Your File</label>
     <input type="file" name="uploadFile" id="uploadFile">                  
</form>
<script>
    $('#uploadFile').change(function(){
        var fileName = this.files[0].name;
        var fileSize = this.files[0].size;
        var fileType = this.files[0].type;
        alert('FileName : ' + fileName + '\nFileSize : ' + fileSize + ' bytes');
    });
</script>

Note: To get the uploading file name means then use jquery val() method.

For Ex:

var fileName = $('#uploadFile').val();

I checked this above code before post, it works perfectly.!

An error occurred while signing: SignTool.exe not found

ClickOnce Publishing Tools are not installed as part of the Typical Installation Options. So you have to install it in advanced mode.

This dialog can be found in Windows 7 by going to Control Panel > Uninstall a program, right-clicking on Microsoft Visual Studio Professional 2015 and selecting Change. A Visual Studio dialog will open up. Select Modify from the set of buttons at the bottom and the above dialog will appear.

Why is Tkinter Entry's get function returning nothing?

A simple example without classes:

from tkinter import *    
master = Tk()

# Create this method before you create the entry
def return_entry(en):
    """Gets and prints the content of the entry"""
    content = entry.get()
    print(content)  

Label(master, text="Input: ").grid(row=0, sticky=W)

entry = Entry(master)
entry.grid(row=0, column=1)

# Connect the entry with the return button
entry.bind('<Return>', return_entry) 

mainloop()

Disable single warning error

If you only want to suppress a warning in a single line of code, you can use the suppress warning specifier:

#pragma warning(suppress: 4101)
// here goes your single line of code where the warning occurs

For a single line of code, this works the same as writing the following:

#pragma warning(push)
#pragma warning(disable: 4101)
// here goes your code where the warning occurs
#pragma warning(pop)

How can I programmatically get the MAC address of an iphone

It's not possible anymore on devices running iOS 7.0 or later, thus unavailable to get MAC address in Swift.

As Apple stated:

In iOS 7 and later, if you ask for the MAC address of an iOS device, the system returns the value 02:00:00:00:00:00. If you need to identify the device, use the identifierForVendor property of UIDevice instead. (Apps that need an identifier for their own advertising purposes should consider using the advertisingIdentifier property of ASIdentifierManager instead.)

Is it possible to play music during calls so that the partner can hear it ? Android

Note: You can play back the audio data only to the standard output device.
Currently, that is the mobile device speaker or a Bluetooth headset. You 
cannot play sound files in the conversation audio during a call.

See official link

http://developer.android.com/guide/topics/media/mediaplayer.html

Error: Can't set headers after they are sent to the client

It is very likely that this is more of a node thing, 99% of the time it's a double callback causing you to respond twice, or next()ing twice etc, damn sure. It solved my problem was using next() inside a loop. Remove the next() from the loop or stop calling it more than one times.

What are the Ruby File.open modes and options?

opt is new for ruby 1.9. The various options are documented in IO.new : www.ruby-doc.org/core/IO.html

Get Application Directory

If you're trying to get access to a file, try the openFileOutput() and openFileInput() methods as described here. They automatically open input/output streams to the specified file in internal memory. This allows you to bypass the directory and File objects altogether which is a pretty clean solution.

How to draw a filled circle in Java?

public void paintComponent(Graphics g) {
   super.paintComponent(g);
   Graphics2D g2d = (Graphics2D)g;
   // Assume x, y, and diameter are instance variables.
   Ellipse2D.Double circle = new Ellipse2D.Double(x, y, diameter, diameter);
   g2d.fill(circle);
   ...
}

Here are some docs about paintComponent (link).

You should override that method in your JPanel and do something similar to the code snippet above.

In your ActionListener you should specify x, y, diameter and call repaint().

Error 330 (net::ERR_CONTENT_DECODING_FAILED):

One more idea for anyone else getting this...

I had some gzipped svg, but it had a php error in the output, which caused this error message. (Because there was text in the middle of gzip binary.) Fixing the php error solved it.

Deleting multiple columns based on column names in Pandas

df = df[[col for col in df.columns if not ('Unnamed' in col)]]

How to find Google's IP address?

The following IP address ranges belong to Google:

64.233.160.0 - 64.233.191.255
66.102.0.0 - 66.102.15.255
66.249.64.0 - 66.249.95.255
72.14.192.0 - 72.14.255.255
74.125.0.0 - 74.125.255.255
209.85.128.0 - 209.85.255.255
216.239.32.0 - 216.239.63.255

Like many popular Web sites, Google utilizes multiple Internet servers to handle incoming requests to its Web site. Instead of entering http://www.google.com/ into the browser, a person can enter http:// followed by one of the above addresses, for example:

http://74.125.224.72/

SOURCE

Add and remove a class on click using jQuery?

Try this in your Head section of the site:

$(function() {
    $('.menu_box_list li').click(function() {
        $('.menu_box_list li.active').removeClass('active');
        $(this).addClass('active');
    });
});

jQuery check if attr = value

jQuery's attr method returns the value of the attribute:

The .attr() method gets the attribute value for only the first element in the matched set. To get the value for each element individually, use a looping construct such as jQuery's .each() or .map() method.

All you need is:

$('html').attr('lang') == 'fr-FR'

However, you might want to do a case-insensitive match:

$('html').attr('lang').toLowerCase() === 'fr-fr'

jQuery's val method returns the value of a form element.

The .val() method is primarily used to get the values of form elements such as input, select and textarea. In the case of <select multiple="multiple"> elements, the .val() method returns an array containing each selected option; if no option is selected, it returns null.

How to prevent colliders from passing through each other?

Edit ---> Project Settings ---> Time ... decrease "Fixed Timestep" value .. This will solve the problem but it can affect performance negatively.
Another solution is could be calculate the coordinates (for example, you have a ball and wall. Ball will hit to wall. So calculate coordinates of wall and set hitting process according these cordinates )

Find unused npm packages in package.json

many of the answer here are how to find unused items.

I wanted to remove them automatically.

Install this node project.

$ npm install -g typescript tslint tslint-etc

At the root dir, add a new file tslint-imports.json

{ "extends": [ "tslint-etc" ], "rules": { "no-unused-declaration": true } }

Run this at your own risk, make a backup :)

$ tslint --config tslint-imports.json --fix --project .

Declaring variables in Excel Cells

I also just found out how to do this with the Excel Name Manager (Formulas > Defined Names Section > Name Manager).

You can define a variable that doesn't have to "live" within a cell and then you can use it in formulas.

Excel Name Manager

JavaScript pattern for multiple constructors

Answering because this question is returned first in google but the answers are now outdated.

You can use Destructuring objects as constructor parameters in ES6

Here's the pattern:

You can't have multiple constructors, but you can use destructuring and default values to do what you want.

export class myClass {

  constructor({ myArray = [1, 2, 3], myString = 'Hello World' }) {

    // ..
  }
}

And you can do this if you want to support a 'parameterless' constructor.

export class myClass {

      constructor({myArray = [1, 2, 3], myString = 'Hello World'} = {}) {

        // ..
      }
}

Where is the Microsoft.IdentityModel dll

I had a similar problem. I got an exception "Type is not resolved for member 'Microsoft.IdentityModel.Claims.ClaimsPrincipal, Microsoft.IdentityModel, Version = 3.5.0.0, Culture = neutral, PublicKeyToken = 31bf3856ad364e35'.".

I tried to run the ASP.NET application from Visual Studio, which was a reference to a local copy of Microsoft.IdentityModel.dll.

I did not want to install the SDK and I had to copy the library to the directory "C: \ Program Files \ Common Files \ Microsoft Shared \ DevServer \ 10.0" and restart Visual Studio.

Static array vs. dynamic array in C++

Yes right the static array is created at the compile time where as the dynamic array is created on the run time. Where as the difference as far is concerned with their memory locations the static are located on the stack and the dynamic are created on the heap. Everything which gets located on heap needs the memory management until and unless garbage collector as in the case of .net framework is present otherwise there is a risk of memory leak.

Spring CORS No 'Access-Control-Allow-Origin' header is present

I also had messages like No 'Access-Control-Allow-Origin' header is present on the requested resource. Origin 'http://localhost:63342' is therefore not allowed access.

I had configured cors properly, but what was missing in webflux in RouterFuncion was accept and contenttype headers APPLICATION_JSON like in this piece of code:

@Bean
RouterFunction<ServerResponse> routes() {
    return route(POST("/create")
                              .and(accept(APPLICATION_JSON))
                              .and(contentType(APPLICATION_JSON)), serverRequest -> create(serverRequest);
}

Angular 2 Date Input not binding to date value

use DatePipe

> // ts file

import { DatePipe } from '@angular/common';

@Component({
....
providers:[DatePipe]
})

export class FormComponent {

constructor(private datePipe : DatePipe){}

    demoUser = new User(0, '', '', '', '', this.datePipe.transform(new Date(), 'yyyy-MM-dd'), '', 0, [], []);  
}

CSS table column autowidth

The following will solve your problem:

td.last {
    width: 1px;
    white-space: nowrap;
}

Flexible, Class-Based Solution

And a more flexible solution is creating a .fitwidth class and applying that to any columns you want to ensure their contents are fit on one line:

td.fitwidth {
    width: 1px;
    white-space: nowrap;
}

And then in your HTML:

<tr>
    <td class="fitwidth">ID</td>
    <td>Description</td>
    <td class="fitwidth">Status</td>
    <td>Notes</td>
</tr>

What's the difference between a null pointer and a void pointer?

A null pointer is guaranteed to not compare equal to a pointer to any object. It's actual value is system dependent and may vary depending on the type. To get a null int pointer you would do

int* p = 0;

A null pointer will be returned by malloc on failure.

We can test if a pointer is null, i.e. if malloc or some other function failed simply by testing its boolean value:

if (p) {
    /* Pointer is not null */
} else {
    /* Pointer is null */
}

A void pointer can point to any type and it is up to you to handle how much memory the referenced objects consume for the purpose of dereferencing and pointer arithmetic.

Replace all spaces in a string with '+'

var str = 'a b c';
var replaced = str.replace(/\s/g, '+');

How to download a file from server using SSH?

Find a line in a file and remove it

Old question, but an easy way is to:

Iterate through file, adding each line to an new array list
iterate through the array, find matching String, then call the remove method.
iterate through array again, printing each line to the file, boolean for append should be false, which basically replaces the file

How to get local server host and port in Spring Boot?

I used to declare the configuration in application.properties like this (you can use you own property file)

server.host = localhost
server.port = 8081

and in application you can get it easily by @Value("${server.host}") and @Value("${server.port}") as field level annotation.

or if in your case it is dynamic than you can get from system properties

Here is the example

@Value("#{systemproperties['server.host']}")
@Value("#{systemproperties['server.port']}")

For a better understanding of this annotation , see this example Multiple uses of @Value annotation

How are software license keys generated?

I realize that this answer is about 10 years late to the party.

A good software license key/serial number generator consists of more than just a string of random characters or a value from some curve generator. Using a limited alphanumeric alphabet, data can be embedded into a short string (e.g. XXXX-XXXX-XXXX-XXXX) that includes all kinds of useful information such as:

Date created or the date the license expires
Product ID, product classification, major and minor version numbers
Custom bits like a hardware hash
Per-user hash checksum bits (e.g. the user enters their email address along with the license key and both pieces of information are used to calculate/verify the hash).

The license key data is then encrypted and then encoded using the limited alphanumeric alphabet. For online validation, the license server holds the secrets for decrypting the information. For offline validation, the decryption secret(s) are included with the software itself along with the decryption/validation code. Obviously, offline validation means the software isn't secure against someone making a keygen.

Probably the hardest part about creating a license key is figuring out how to cram as much data as possible into as few bytes as possible. Remember that users will be entering in their license keys by hand, so every bit counts and users don't want to type extremely long, complex strings in. 16 to 25 character license keys are the most common and balance how much data can be placed into a key vs. user tolerance for entering the key to unlock the software. Slicing up bytes into chunks of bits allows for more information to be included but does increase code complexity of both the generator and validator.

Encryption is a complex topic. In general, standard encryption algorithms like AES have block sizes that don't align with the goal of keeping license key lengths short. Therefore, most developers making their own license keys end up writing their own encryption algorithms (an activity which is frequently discouraged) or don't encrypt keys at all, which guarantees that someone will write a keygen. Suffice it to say that good encryption is hard to do right and a decent understanding of how Feistel networks and existing ciphers work are prerequisites.

Verifying a key is a matter of decoding and decrypting the string, verifying the hash/checksum, checking the product ID and major and minor version numbers in the data, verifying that the license hasn't expired, and doing whatever other checks need to be performed.

Writing a keygen is a matter of knowing what a license key consists of and then producing the same output that the original key generator produces. If the algorithm for license key verification is included in and used by the software, then it is just a matter of creating software that does the reverse of the verification process.

To see what the entire process looks like, here is a blog post I recently wrote that goes over choosing the license key length, the data layout, the encryption algorithm, and the final encoding scheme:

https://cubicspot.blogspot.com/2020/03/adventuring-deeply-into-software-serial.html

A practical, real-world implementation of the key generator and key verifier from the blog post can be seen here:

https://github.com/cubiclesoft/php-misc/blob/master/support/serial_number.php

Documentation for the above class:

https://github.com/cubiclesoft/php-misc/blob/master/docs/serial_number.md

A production-ready open source license server that generates and manages license keys using the above serial number code can be found here:

https://github.com/cubiclesoft/php-license-server

The above license server supports both online and offline validation modes. A software product might start its existence with online only validation. When the software product is ready to retire and no longer supported, it can easily move to offline validation where all existing keys continue to work once the user upgrades to the very last version of the software that switches over to offline validation.

A live demo of how the above license server can be integrated into a website to sell software licenses plus an installable demo application can be found here (both the website and demo app are open source too):

https://license-server-demo.cubiclesoft.com/

Full disclosure: I'm the author of both the license server and the demo site software.

How to block until an event is fired in c#

A very easy kind of event you can wait for is the ManualResetEvent, and even better, the ManualResetEventSlim.

They have a WaitOne() method that does exactly that. You can wait forever, or set a timeout, or a "cancellation token" which is a way for you to decide to stop waiting for the event (if you want to cancel your work, or your app is asked to exit).

You fire them calling Set().

Here is the doc.

Memory address of an object in C#

Instead of this code, you should call GetHashCode(), which will return a (hopefully-)unique value for each instance.

You can also use the ObjectIDGenerator class, which is guaranteed to be unique.

Regular expression to stop at first match

You need to make your regular expression non-greedy, because by default, "(.*)" will match all of "file path/level1/level2" xxx some="xxx".

Instead you can make your dot-star non-greedy, which will make it match as few characters as possible:

/location="(.*?)"/

Adding a ? on a quantifier (?, * or +) makes it non-greedy.

How to clear jQuery validation error messages?

If you want to simply hide the errors:

$("#clearButton").click(function() {
  $("label.error").hide();
  $(".error").removeClass("error");
});

If you specified the errorClass, call that class to hide instead error (the default) I used above.

Difference between exit(0) and exit(1) in Python

How to add constraints programmatically using Swift

The error is caused by constrains automatically created from autoresizing mask, they are created because UIView property translatesAutoresizingMaskIntoConstraints is true by default.

Consider using BoxView to get rid of all manual constraint creation boilerplate, and make your code concize and readable. To make layout in question with BoxView is very easy:

boxView.items = [
   new_view.boxed.centerX().centerY().relativeWidth(1.0).relativeHeight(1.0)
]

SQL Greater than, Equal to AND Less Than

declare @starttime datetime = '2012-03-07 22:58:00'

SELECT BookingId, StartTime
FROM Booking
WHERE ABS( DATEDIFF( minute, StartTime, @starttime ) ) <= 60

Does SVG support embedding of bitmap images?

Yes, you can reference any image from the image element. And you can use data URIs to make the SVG self-contained. An example:

<svg xmlns="http://www.w3.org/2000/svg"
     xmlns:xlink="http://www.w3.org/1999/xlink">

    ...
    <image
        width="100" height="100"
        xlink:href="data:image/png;base64,IMAGE_DATA"
        />
    ...
</svg>

The svg element attribute xmlns:xlink declares xlink as a namespace prefix and says where the definition is. That then allows the SVG reader to know what xlink:href means.

The IMAGE_DATA is where you'd add the image data as base64-encoded text. Vector graphics editors that support SVG usually have an option for saving with images embedded. Otherwise there are plenty of tools around for encoding a byte stream to and from base64.

Here's a full example from the SVG testsuite.

How to restart Postgresql

macOS:

On the top left of the MacOS menu bar you have the Postgres Icon
Click on it this opens a drop down menu
Click on Stop -> than click on start

PHP not displaying errors even though display_errors = On

I have encountered also the problem. Finally I found the solution. I am using UBUNTU 16.04 LTS.

1) Open the /ect/php/7.0/apache2/php.ini file (under the /etc/php one might have different version of PHP but apache2/php.ini will be under the version file), find ERROR HANDLING AND LOGGING section and set the following value {display_error = On, error_reporting = E_ALL}.

NOTE - Under the QUICK REFERENCE section also one can find these values directives but don't change there just change in Section I told.

2) Restart Apache server sudo systemctl restart apache2

How to specify the JDK version in android studio?

For new Android Studio versions, go to C:\Program Files\Android\Android Studio\jre\bin(or to location of Android Studio installed files) and open command window at this location and type in following command in command prompt:-

java -version

setState() inside of componentDidUpdate()

This example will help you to understand the React Life Cycle Hooks.

You can setState in getDerivedStateFromProps method i.e. static and trigger the method after props change in componentDidUpdate.

In componentDidUpdate you will get 3rd param which returns from getSnapshotBeforeUpdate.

You can check this codesandbox link

_x000D_

// Child component_x000D_
class Child extends React.Component {_x000D_
  // First thing called when component loaded_x000D_
  constructor(props) {_x000D_
    console.log("constructor");_x000D_
    super(props);_x000D_
    this.state = {_x000D_
      value: this.props.value,_x000D_
      color: "green"_x000D_
    };_x000D_
  }_x000D_
_x000D_
  // static method_x000D_
  // dont have access of 'this'_x000D_
  // return object will update the state_x000D_
  static getDerivedStateFromProps(props, state) {_x000D_
    console.log("getDerivedStateFromProps");_x000D_
    return {_x000D_
      value: props.value,_x000D_
      color: props.value % 2 === 0 ? "green" : "red"_x000D_
    };_x000D_
  }_x000D_
_x000D_
  // skip render if return false_x000D_
  shouldComponentUpdate(nextProps, nextState) {_x000D_
    console.log("shouldComponentUpdate");_x000D_
    // return nextState.color !== this.state.color;_x000D_
    return true;_x000D_
  }_x000D_
_x000D_
  // In between before real DOM updates (pre-commit)_x000D_
  // has access of 'this'_x000D_
  // return object will be captured in componentDidUpdate_x000D_
  getSnapshotBeforeUpdate(prevProps, prevState) {_x000D_
    console.log("getSnapshotBeforeUpdate");_x000D_
    return { oldValue: prevState.value };_x000D_
  }_x000D_
_x000D_
  // Calls after component updated_x000D_
  // has access of previous state and props with snapshot_x000D_
  // Can call methods here_x000D_
  // setState inside this will cause infinite loop_x000D_
  componentDidUpdate(prevProps, prevState, snapshot) {_x000D_
    console.log("componentDidUpdate: ", prevProps, prevState, snapshot);_x000D_
  }_x000D_
_x000D_
  static getDerivedStateFromError(error) {_x000D_
    console.log("getDerivedStateFromError");_x000D_
    return { hasError: true };_x000D_
  }_x000D_
_x000D_
  componentDidCatch(error, info) {_x000D_
    console.log("componentDidCatch: ", error, info);_x000D_
  }_x000D_
_x000D_
  // After component mount_x000D_
  // Good place to start AJAX call and initial state_x000D_
  componentDidMount() {_x000D_
    console.log("componentDidMount");_x000D_
    this.makeAjaxCall();_x000D_
  }_x000D_
_x000D_
  makeAjaxCall() {_x000D_
    console.log("makeAjaxCall");_x000D_
  }_x000D_
_x000D_
  onClick() {_x000D_
    console.log("state: ", this.state);_x000D_
  }_x000D_
_x000D_
  render() {_x000D_
    return (_x000D_
      <div style={{ border: "1px solid red", padding: "0px 10px 10px 10px" }}>_x000D_
        <p style={{ color: this.state.color }}>Color: {this.state.color}</p>_x000D_
        <button onClick={() => this.onClick()}>{this.props.value}</button>_x000D_
      </div>_x000D_
    );_x000D_
  }_x000D_
}_x000D_
_x000D_
// Parent component_x000D_
class Parent extends React.Component {_x000D_
  constructor(props) {_x000D_
    super(props);_x000D_
    this.state = { value: 1 };_x000D_
_x000D_
    this.tick = () => {_x000D_
      this.setState({_x000D_
        date: new Date(),_x000D_
        value: this.state.value + 1_x000D_
      });_x000D_
    };_x000D_
  }_x000D_
_x000D_
  componentDidMount() {_x000D_
    setTimeout(this.tick, 2000);_x000D_
  }_x000D_
_x000D_
  render() {_x000D_
    return (_x000D_
      <div style={{ border: "1px solid blue", padding: "0px 10px 10px 10px" }}>_x000D_
        <p>Parent</p>_x000D_
        <Child value={this.state.value} />_x000D_
      </div>_x000D_
    );_x000D_
  }_x000D_
}_x000D_
_x000D_
function App() {_x000D_
  return (_x000D_
    <React.Fragment>_x000D_
      <Parent />_x000D_
    </React.Fragment>_x000D_
  );_x000D_
}_x000D_
_x000D_
const rootElement = document.getElementById("root");_x000D_
ReactDOM.render(<App />, rootElement);

_x000D_

<div id="root"></div>_x000D_
<script src="https://cdnjs.cloudflare.com/ajax/libs/react/16.6.3/umd/react.production.min.js"></script>_x000D_
<script src="https://cdnjs.cloudflare.com/ajax/libs/react-dom/16.6.3/umd/react-dom.production.min.js"></script>

_x000D_

Difference between int32, int, int32_t, int8 and int8_t

The _t data types are typedef types in the stdint.h header, while int is an in built fundamental data type. This make the _t available only if stdint.h exists. int on the other hand is guaranteed to exist.

html tables & inline styles

This should do the trick:

<table width="400" border="0" cellpadding="0" cellspacing="0">
  <tr>
    <td width="50" height="40" valign="top" rowspan="3">
      <img alt="" src="" width="40" height="40" style="margin: 0; border: 0; padding: 0; display: block;">
    </td>
    <td width="350" height="40" style="font-family: Helvetica, Arial, sans-serif; font-size: 14px; color: #000000;">
<a href="" style="color: #D31145; font-weight: bold; text-decoration: none;">LAST FIRST</a><br>
REALTOR | P 123.456.789
    </td>
  </tr>
  <tr>
    <td width="350" height="70" valign="bottom" style="font-family: Helvetica, Arial, sans-serif; font-size: 14px; color: #000000;">
<img alt="" src="" width="200" height="60" style="margin: 0; border: 0; padding: 0; display: block;">
    </td>
  </tr>
  <tr>
    <td width="350" height="20" valign="bottom" style="font-family: Helvetica, Arial, sans-serif; font-size: 10px; color: #000000;">
all your minor text here | all your minor text here | all your minor text here
    </td>
  </tr>
</table>

UPDATE: Adjusted code per the comments:

After viewing your jsFiddle, an important thing to note about tables is that table cell widths in each additional row all have to be the same width as the first, and all cells must add to the total width of your table.

Here is an example that will NOT WORK:

<table width="600" border="0" cellpadding="0" cellspacing="0">
  <tr>
    <td width="200" bgcolor="#252525">&nbsp;
    </td>
    <td width="400" bgcolor="#454545">&nbsp;
    </td>
  </tr>
  <tr>
    <td width="300" bgcolor="#252525">&nbsp;
    </td>
    <td width="300" bgcolor="#454545">&nbsp;
    </td>
  </tr>
</table>

Although the 2nd row does add up to 600, it (and any additional rows) must have the same 200-400 split as the first row, unless you are using colspans. If you use a colspan, you could have one row, but it needs to have the same width as the cells it is spanning, so this works:

<table width="600" border="0" cellpadding="0" cellspacing="0">
  <tr>
    <td width="200" bgcolor="#252525">&nbsp;
    </td>
    <td width="400" bgcolor="#454545">&nbsp;
    </td>
  </tr>
  <tr>
    <td width="600" colspan="2" bgcolor="#353535">&nbsp;
    </td>
  </tr>
</table>

Not a full tutorial, but I hope that helps steer you in the right direction in the future.

Here is the code you are after:

<table width="900" border="0" cellpadding="0" cellspacing="0">
  <tr>
    <td width="57" height="43" valign="top" rowspan="2">
      <img alt="Rashel Adragna" src="http://zoparealtygroup.com/wp-content/uploads/2013/10/sig_head.png" width="47" height="43" style="margin: 0; border: 0; padding: 0; display: block;">
    </td>
    <td width="843" height="43" style="font-family: Helvetica, Arial, sans-serif; font-size: 14px; color: #000000;">
<a href="" style="color: #D31145; font-weight: bold; text-decoration: none;">RASHEL ADRAGNA</a><br>
REALTOR | P 855.900.24KW
    </td>
  </tr>
  <tr>
    <td width="843" height="64" valign="bottom" style="font-family: Helvetica, Arial, sans-serif; font-size: 14px; color: #000000;">
<img alt="Zopa Realty Group logo" src="http://zoparealtygroup.com/wp-content/uploads/2013/10/sig_logo.png" width="177" height="54" style="margin: 0; border: 0; padding: 0; display: block;">
    </td>
  </tr>
  <tr>
    <td width="843" colspan="2" height="20" valign="bottom" align="center" style="font-family: Helvetica, Arial, sans-serif; font-size: 10px; color: #000000;">
all your minor text here | all your minor text here | all your minor text here
    </td>
  </tr>
</table>

You'll note that I've added an extra 10px to some of your table cells. This in combination with align/valigns act as padding between your cells. It is a clever way to aviod actually having to add padding, margins or empty padding cells.

Oracle PL/SQL - Raise User-Defined Exception With Custom SQLERRM

declare
   z exception;

begin
   if to_char(sysdate,'day')='sunday' then
     raise z;
   end if;

   exception 
     when z then
        dbms_output.put_line('to day is sunday');
end;

Html- how to disable <a href>?

<script>
    $(document).ready(function(){
        $('#connectBtn').click(function(e){
            e.preventDefault();
        })
    });
</script>

This will prevent the default action.

Angular 2.0 router not working on reloading the browser

Just adding .htaccess in root resolved 404 while refreshing the page in angular 4 apache2.

<IfModule mod_rewrite.c>
    RewriteEngine on

    # Don't rewrite files or directories
    RewriteCond %{REQUEST_FILENAME} -f [OR]
    RewriteCond %{REQUEST_FILENAME} -d
    RewriteRule ^ - [L]

    # Rewrite everything else to index.html
    # to allow html5 state links
    RewriteRule ^ index.html [L]
</IfModule>

How to access your website through LAN in ASP.NET

You may also need to enable the World Wide Web Service inbound firewall rule.

On Windows 7: Start -> Control Panel -> Windows Firewall -> Advanced Settings -> Inbound Rules

Find World Wide Web Services (HTTP Traffic-In) in the list and select to enable the rule. Change is pretty much immediate.

jQuery: Best practice to populate drop down?

I found this to be working from jquery site

$.getJSON( "/Admin/GetFolderList/", function( data ) {
  var options = $("#dropdownID");
  $.each( data, function(key, val) {
    options.append(new Option(key, val));
  });
});

How to create an executable .exe file from a .m file

I developed a non-matlab software for direct compilation of m-files (TMC Compiler). This is an open-source converter of m-files projects to C. The compiler produces the C code that may be linked with provided open-source run-time library to produce a stand-alone application. The library implements a set of build-in functions; the linear-algebra operations use LAPACK code. It is possible to expand the set of the build-in functions by custom implementation as described in the documentation.

Java how to sort a Linked List?

I wouldn't. I would use an ArrayList or a sorted collection with a Comparator. Sorting a LinkedList is about the most inefficient procedure I can think of.

How do I get the Date & Time (VBS)

To expound on Numenor's answer you can do something like, Format(Now(),"HH:mm:ss") using these custom date/time formating options

For everyone who is tempted to downvote this answer please be aware that the question was originally tagged VB and vbscript hence my answer, the VB tag was edited out leaving only the vbscript tag. The OP accepted this answer which I take to mean that it gave him the information that he needed.

CodeIgniter activerecord, retrieve last insert id?

$this->db->insert_id()

//please try this

GnuPG: "decryption failed: secret key not available" error from gpg on Windows

when reimporting your keys from the old keyring, you need to specify the command:

gpg --allow-secret-key-import --import <keyring>

otherwise it will only import the public keys, not the private keys.

excel formula to subtract number of days from a date

Say the 1st date is in A1 cell & the 2nd date is in B1 cell

Make sure that the cell type of both A1 & B1 is DATE.
Then simply put the following formula in C1:

=A1-B1

The result of this formula may look funny to you. Then Change the Cell type of C1 to GENERAL.

It will give you the difference in Days.

You can also use this formula to get the remaining days of year or change the formula as you need:

=365-(A1-B1)

C# Error "The type initializer for ... threw an exception

I got this error when I modified an Nlog configuration file and didn't format the XML correctly.

How do I capitalize first letter of first name and last name in C#?

TextInfo.ToTitleCase() capitalizes the first character in each token of a string.
If there is no need to maintain Acronym Uppercasing, then you should include ToLower().

string s = "JOHN DOE";
s = CultureInfo.CurrentCulture.TextInfo.ToTitleCase(s.ToLower());
// Produces "John Doe"

If CurrentCulture is unavailable, use:

string s = "JOHN DOE";
s = new System.Globalization.CultureInfo("en-US", false).TextInfo.ToTitleCase(s.ToLower());

See the MSDN Link for a detailed description.

How to flush output after each `echo` call?

Sometimes, the problem come from Apache settings. Apache can be set to gzip the output. In the file .htaccess you can add for instance :

SetEnv no-gzip 1

Data was not saved: object references an unsaved transient instance - save the transient instance before flushing

I had the same problem. In my case it arises, because the lookup-table "country" has an existing record with countryId==0 and a primitive primary key and I try to save a User with a countryID==0. Change the primary key of country to Integer. Now Hibernate can identify new records.

For the recommendation of using wrapper classes as primary key see this stackoverflow question

Where is `%p` useful with printf?

When you need to debug, use printf with %p option is really helpful. You see 0x0 when you have a NULL value.

Google server putty connect 'Disconnected: No supported authentication methods available (server sent: publickey)

If the private key has been generated with ssh-keygen in Linux it needs to be converted with puttygen because Putty does not support openssh keys.

Start puttygen, and click on Conversions - Import key, then click Browse and select the private key generated with openssh, then click on Save private key.

Use your new key to connect.

List names of all tables in a SQL Server 2012 schema

Your should really use the INFORMATION_SCHEMA views in your database:

USE <your_database_name>
GO
SELECT * FROM INFORMATION_SCHEMA.TABLES

You can then filter that by table schema and/or table type, e.g.

SELECT * FROM INFORMATION_SCHEMA.TABLES WHERE TABLE_TYPE='BASE TABLE'

Change onclick action with a Javascript function

var Foo = function(){
    document.getElementById( "a" ).setAttribute( "onClick", "javascript: Boo();" );
}

var Boo = function(){
    alert("test");
}

Check if datetime instance falls in between other two datetime objects

Do simple compare > and <.

if (dateA>dateB && dateA<dateC)
    //do something

If you care only on time:

if (dateA.TimeOfDay>dateB.TimeOfDay && dateA.TimeOfDay<dateC.TimeOfDay)
    //do something

SQL to search objects, including stored procedures, in Oracle

i reached this question while trying to find all procedures which use a certain table

Oracle SQL Developer offers this capability, as pointed out in this article : https://www.thatjeffsmith.com/archive/2012/09/search-and-browse-database-objects-with-oracle-sql-developer/

From the View menu, choose Find DB Object. Choose a DB connection. Enter the name of the table. At Object Types, keep only functions, procedures and packages. At Code section, check All source lines.

java.lang.NoClassDefFoundError: org/apache/juli/logging/LogFactory

This happened to me because I was using a Tomcat 5.5 catalina.sh file with a Tomcat 7 installation. Using the catalina.sh that came with the Tomcat 7 install fixed the problem.

What's the difference between passing by reference vs. passing by value?

Many answers here (and in particular the most highly upvoted answer) are factually incorrect, since they misunderstand what "call by reference" really means. Here's my attempt to set matters straight.

TL;DR

In simplest terms:

call by value means that you pass values as function arguments
call by reference means that you pass variables as function arguments

In metaphoric terms:

Call by value is where I write down something on a piece of paper and hand it to you. Maybe it's a URL, maybe it's a complete copy of War and Peace. No matter what it is, it's on a piece of paper which I've given to you, and so now it is effectively your piece of paper. You are now free to scribble on that piece of paper, or use that piece of paper to find something somewhere else and fiddle with it, whatever.
Call by reference is when I give you my notebook which has something written down in it. You may scribble in my notebook (maybe I want you to, maybe I don't), and afterwards I keep my notebook, with whatever scribbles you've put there. Also, if what either you or I wrote there is information about how to find something somewhere else, either you or I can go there and fiddle with that information.

What "call by value" and "call by reference" don't mean

Note that both of these concepts are completely independent and orthogonal from the concept of reference types (which in Java is all types that are subtypes of Object, and in C# all class types), or the concept of pointer types like in C (which are semantically equivalent to Java's "reference types", simply with different syntax).

The notion of reference type corresponds to a URL: it is both itself a piece of information, and it is a reference (a pointer, if you will) to other information. You can have many copies of a URL in different places, and they don't change what website they all link to; if the website is updated then every URL copy will still lead to the updated information. Conversely, changing the URL in any one place won't affect any other written copy of the URL.

Note that C++ has a notion of "references" (e.g. int&) that is not like Java and C#'s "reference types", but is like "call by reference". Java and C#'s "reference types", and all types in Python, are like what C and C++ call "pointer types" (e.g. int*).

OK, here's the longer and more formal explanation.

Terminology

To start with, I want to highlight some important bits of terminology, to help clarify my answer and to ensure we're all referring to the same ideas when we are using words. (In practice, I believe the vast majority of confusion about topics such as these stems from using words in ways that to not fully communicate the meaning that was intended.)

To start, here's an example in some C-like language of a function declaration:

void foo(int param) {  // line 1
  param += 1;
}

And here's an example of calling this function:

void bar() {
  int arg = 1;  // line 2
  foo(arg);     // line 3
}

Using this example, I want to define some important bits of terminology:

foo is a function declared on line 1 (Java insists on making all functions methods, but the concept is the same without loss of generality; C and C++ make a distinction between declaration and definition which I won't go into here)
param is a formal parameter to foo, also declared on line 1
arg is a variable, specifically a local variable of the function bar, declared and initialized on line 2
arg is also an argument to a specific invocation of foo on line 3

There are two very important sets of concepts to distinguish here. The first is value versus variable:

A value is the result of evaluating an expression in the language. For example, in the bar function above, after the line int arg = 1;, the expression arg has the value 1.
A variable is a container for values. A variable can be mutable (this is the default in most C-like languages), read-only (e.g. declared using Java's final or C#'s readonly) or deeply immutable (e.g. using C++'s const).

The other important pair of concepts to distinguish is parameter versus argument:

A parameter (also called a formal parameter) is a variable which must be supplied by the caller when calling a function.
An argument is a value that is supplied by the caller of a function to satisfy a specific formal parameter of that function

Call by value

In call by value, the function's formal parameters are variables that are newly created for the function invocation, and which are initialized with the values of their arguments.

This works exactly the same way that any other kinds of variables are initialized with values. For example:

int arg = 1;
int another_variable = arg;

Here arg and another_variable are completely independent variables -- their values can change independently of each other. However, at the point where another_variable is declared, it is initialized to hold the same value that arg holds -- which is 1.

Since they are independent variables, changes to another_variable do not affect arg:

int arg = 1;
int another_variable = arg;
another_variable = 2;

assert arg == 1; // true
assert another_variable == 2; // true

This is exactly the same as the relationship between arg and param in our example above, which I'll repeat here for symmetry:

void foo(int param) {
  param += 1;
}

void bar() {
  int arg = 1;
  foo(arg);
}

It is exactly as if we had written the code this way:

// entering function "bar" here
int arg = 1;
// entering function "foo" here
int param = arg;
param += 1;
// exiting function "foo" here
// exiting function "bar" here

That is, the defining characteristic of what call by value means is that the callee (foo in this case) receives values as arguments, but has its own separate variables for those values from the variables of the caller (bar in this case).

Going back to my metaphor above, if I'm bar and you're foo, when I call you, I hand you a piece of paper with a value written on it. You call that piece of paper param. That value is a copy of the value I have written in my notebook (my local variables), in a variable I call arg.

(As an aside: depending on hardware and operating system, there are various calling conventions about how you call one function from another. The calling convention is like us deciding whether I write the value on a piece of my paper and then hand it to you, or if you have a piece of paper that I write it on, or if I write it on the wall in front of both of us. This is an interesting subject as well, but far beyond the scope of this already long answer.)

Call by reference

In call by reference, the function's formal parameters are simply new names for the same variables that the caller supplies as arguments.

Going back to our example above, it's equivalent to:

// entering function "bar" here
int arg = 1;
// entering function "foo" here
// aha! I note that "param" is just another name for "arg"
arg /* param */ += 1;
// exiting function "foo" here
// exiting function "bar" here

Since param is just another name for arg -- that is, they are the same variable, changes to param are reflected in arg. This is the fundamental way in which call by reference differs from call by value.

Very few languages support call by reference, but C++ can do it like this:

void foo(int& param) {
  param += 1;
}

void bar() {
  int arg = 1;
  foo(arg);
}

In this case, param doesn't just have the same value as arg, it actually is arg (just by a different name) and so bar can observe that arg has been incremented.

Note that this is not how any of Java, JavaScript, C, Objective-C, Python, or nearly any other popular language today works. This means that those languages are not call by reference, they are call by value.

Addendum: call by object sharing

If what you have is call by value, but the actual value is a reference type or pointer type, then the "value" itself isn't very interesting (e.g. in C it's just an integer of a platform-specific size) -- what's interesting is what that value points to.

If what that reference type (that is, pointer) points to is mutable then an interesting effect is possible: you can modify the pointed-to value, and the caller can observe changes to the pointed-to value, even though the caller cannot observe changes to the pointer itself.

To borrow the analogy of the URL again, the fact that I gave you a copy of the URL to a website is not particularly interesting if the thing we both care about is the website, not the URL. The fact that you scribbling over your copy of the URL doesn't affect my copy of the URL isn't a thing we care about (and in fact, in languages like Java and Python the "URL", or reference type value, can't be modified at all, only the thing pointed to by it can).

Barbara Liskov, when she invented the CLU programming language (which had these semantics), realized that the existing terms "call by value" and "call by reference" weren't particularly useful for describing the semantics of this new language. So she invented a new term: call by object sharing.

When discussing languages that are technically call by value, but where common types in use are reference or pointer types (that is: nearly every modern imperative, object-oriented, or multi-paradigm programming language), I find it's a lot less confusing to simply avoid talking about call by value or call by reference. Stick to call by object sharing (or simply call by object) and nobody will be confused. :-)

Define a global variable in a JavaScript function

    var Global = 'Global';

    function LocalToGlobalVariable() {

        // This creates a local variable.

        var Local = '5';

        // Doing this makes the variable available for one session
        // (a page refresh - it's the session not local)

        sessionStorage.LocalToGlobalVar = Local;

        // It can be named anything as long as the sessionStorage
        // references the local variable.
        // Otherwise it won't work.
        // This refreshes the page to make the variable take
        // effect instead of the last variable set.

        location.reload(false);
    };

    // This calls the variable outside of the function for whatever use you want.

    sessionStorage.LocalToGlobalVar;

I realize there is probably a lot of syntax errors in this but its the general idea... Thanks so much LayZee for pointing this out... You can find what a local and session Storage is at http://www.w3schools.com/html/html5_webstorage.asp. I have needed the same thing for my code and this was a really good idea.

How to Retrieve value from JTextField in Java Swing?

import java.awt.*;
import java.awt.event.*;
import javax.swing.*;

public class Swingtest extends JFrame implements ActionListener
{
    JTextField txtdata;
    JButton calbtn = new JButton("Calculate");

    public Swingtest()
    {
        JPanel myPanel = new JPanel();
        add(myPanel);
        myPanel.setLayout(new GridLayout(3, 2));
        myPanel.add(calbtn);
        calbtn.addActionListener(this);
        txtdata = new JTextField();
        myPanel.add(txtdata);
    }

    public void actionPerformed(ActionEvent e)
    {
        if (e.getSource() == calbtn) {
            String data = txtdata.getText(); //perform your operation
            System.out.println(data);
        }
    }

    public static void main(String args[])
    {
        Swingtest g = new Swingtest();
        g.setLocation(10, 10);
        g.setSize(300, 300);
        g.setVisible(true);
    }
}

now its working

php is null or empty?

Just to addon if someone is dealing with  , this would work if dealing with  .

Replace it with str_replace() first and check it with empty()

empty(str_replace("&nbsp;" ,"" , $YOUR_DATA)) ? $YOUR_DATA = '--' : $YOUR_DATA;

Access denied for user 'root'@'localhost' (using password: YES) (Mysql::Error)

You need to grant access to root from localhost. Check this ubuntu help

How to recursively download a folder via FTP on Linux

Just to complement the answer given by Thibaut Barrère.

I used

wget -r -nH --cut-dirs=5 -nc ftp://user:pass@server//absolute/path/to/directory

Note the double slash after the server name. If you don't put an extra slash the path is relative to the home directory of user.

-nH avoids the creation of a directory named after the server name
-nc avoids creating a new file if it already exists on the destination (it is just skipped)
--cut-dirs=5 allows to take the content of /absolute/path/to/directory and to put it in the directory where you launch wget. The number 5 is used to filter out the 5 components of the path. The double slash means an extra component.

Define a fixed-size list in Java

A Java list is a collection of objects ... the elements of a list. The size of the list is the number of elements in that list. If you want that size to be fixed, that means that you cannot either add or remove elements, because adding or removing elements would violate your "fixed size" constraint.

The simplest way to implement a "fixed sized" list (if that is really what you want!) is to put the elements into an array and then Arrays.asList(array) to create the list wrapper. The wrapper will allow you to do operations like get and set, but the add and remove operations will throw exceptions.

And if you want to create a fixed-sized wrapper for an existing list, then you could use the Apache commons FixedSizeList class. But note that this wrapper can't stop something else changing the size of the original list, and if that happens the wrapped list will presumably reflect those changes.

On the other hand, if you really want a list type with a fixed limit (or limits) on its size, then you'll need to create your own List class to implement this. For example, you could create a wrapper class that implements the relevant checks in the various add / addAll and remove / removeAll / retainAll operations. (And in the iterator remove methods if they are supported.)

So why doesn't the Java Collections framework implement these? Here's why I think so:

Use-cases that need this are rare.
The use-cases where this is needed, there are different requirements on what to do when an operation tries to break the limits; e.g. throw exception, ignore operation, discard some other element to make space.
A list implementation with limits could be problematic for helper methods; e.g. Collections.sort.

Is there any good dynamic SQL builder library in Java?

ddlutils is my best choice:http://db.apache.org/ddlutils/api/org/apache/ddlutils/platform/SqlBuilder.html

here is create example(groovy):

Platform platform  = PlatformFactory.createNewPlatformInstance("oracle");//db2,...
//create schema    
def db =        new Database();
def t = new Table(name:"t1",description:"XXX");
def col1 = new Column(primaryKey:true,name:"id",type:"bigint",required:true);
t.addColumn(col1);
t.addColumn(new Column(name:"c2",type:"DECIMAL",size:"8,2"));
t.addColumn( new Column(name:"c3",type:"varchar"));
t.addColumn(new Column(name:"c4",type:"TIMESTAMP",description:"date"));        
db.addTable(t);
println platform.getCreateModelSql(db, false, false)

//you can read Table Object from  platform.readModelFromDatabase(....)
def sqlbuilder = platform.getSqlBuilder();
println "insert:"+sqlbuilder.getInsertSql(t,["id":1,c2:3],false);
println "update:"+sqlbuilder.getUpdateSql(t,["id":1,c2:3],false);
println "delete:"+sqlbuilder.getDeleteSql(t,["id":1,c2:3],false);
//http://db.apache.org/ddlutils/database-support.html

DIV :after - add content after DIV

Position your <div> absolutely at the bottom and don't forget to give div.A a position: relative - http://jsfiddle.net/TTaMx/

    .A {
        position: relative;
        margin: 40px 0;
        height: 40px;
        width: 200px;
        background: #eee;
    }

    .A:after {
        content: " ";
        display: block;
        background: #c00;
        height: 29px;
        width: 100%;

        position: absolute;
        bottom: -29px;
    }?

Decimal separator comma (',') with numberDecimal inputType in EditText

You could do the following:

DecimalFormatSymbols d = DecimalFormatSymbols.getInstance(Locale.getDefault());
input.setFilters(new InputFilter[] { new DecimalDigitsInputFilter(5, 2) });
input.setKeyListener(DigitsKeyListener.getInstance("0123456789" + d.getDecimalSeparator()));

And then you could use an input filter:

    public class DecimalDigitsInputFilter implements InputFilter {

Pattern mPattern;

public DecimalDigitsInputFilter(int digitsBeforeZero, int digitsAfterZero) {
    DecimalFormatSymbols d = new DecimalFormatSymbols(Locale.getDefault());
    String s = "\\" + d.getDecimalSeparator();
    mPattern = Pattern.compile("[0-9]{0," + (digitsBeforeZero - 1) + "}+((" + s + "[0-9]{0," + (digitsAfterZero - 1) + "})?)||(" + s + ")?");
}

@Override
public CharSequence filter(CharSequence source, int start, int end, Spanned dest, int dstart, int dend) {

    Matcher matcher = mPattern.matcher(dest);
    if (!matcher.matches())
        return "";
    return null;
}

}

Why are the Level.FINE logging messages not showing?

This solution appears better to me, regarding maintainability and design for change:

Create the logging property file embedding it in the resource project folder, to be included in the jar file:

# Logging
handlers = java.util.logging.ConsoleHandler
.level = ALL

# Console Logging
java.util.logging.ConsoleHandler.level = ALL

Load the property file from code:

public static java.net.URL retrieveURLOfJarResource(String resourceName) {
   return Thread.currentThread().getContextClassLoader().getResource(resourceName);
}

public synchronized void initializeLogger() {
   try (InputStream is = retrieveURLOfJarResource("logging.properties").openStream()) {
      LogManager.getLogManager().readConfiguration(is);
   } catch (IOException e) {
      // ...
   }
}

LDAP filter for blank (empty) attribute

Search for a null value by using \00

For example:

ldapsearch -D cn=admin -w pass -s sub -b ou=users,dc=acme 'manager=\00' uid manager

Make sure if you use the null value on the command line to use quotes around it to prevent the OS shell from sending a null character to LDAP. For example, this won't work:

 ldapsearch -D cn=admin -w pass -s sub -b ou=users,dc=acme manager=\00 uid manager

There are various sites that reference this, along with other special characters. Example:

How to find the statistical mode?

There is package modeest which provide estimators of the mode of univariate unimodal (and sometimes multimodal) data and values of the modes of usual probability distributions.

mySamples <- c(19, 4, 5, 7, 29, 19, 29, 13, 25, 19)

library(modeest)
mlv(mySamples, method = "mfv")

Mode (most likely value): 19 
Bickel's modal skewness: -0.1 
Call: mlv.default(x = mySamples, method = "mfv")

For more information see this page

How can I get a resource content from a static context?

Another solution:

If you have a static subclass in a non-static outer class, you can access the resources from within the subclass via static variables in the outer class, which you initialise on creation of the outer class. Like

public class Outerclass {

    static String resource1

    public onCreate() {
        resource1 = getString(R.string.text);
    }

    public static class Innerclass {

        public StringGetter (int num) {
            return resource1; 
        }
    }
}

I used it for the getPageTitle(int position) Function of the static FragmentPagerAdapter within my FragmentActivity which is useful because of I8N.

Windows equivalent of the 'tail' command

set /p line= < file.csv 
echo %line%

it will return first line of your file in cmd Windows in variable %line%.

Markdown and image alignment

You can embed HTML in Markdown, so you can do something like this:

<img style="float: right;" src="whatever.jpg">

Continue markdown text...

How to stretch children to fill cross-axis?

The children of a row-flexbox container automatically fill the container's vertical space.
Specify flex: 1; for a child if you want it to fill the remaining horizontal space:

_x000D_

.wrapper {_x000D_
  display: flex;_x000D_
  flex-direction: row;_x000D_
  align-items: stretch;_x000D_
  width: 100%;_x000D_
  height: 5em;_x000D_
  background: #ccc;_x000D_
}_x000D_
.wrapper > .left_x000D_
{_x000D_
  background: #fcc;_x000D_
}_x000D_
.wrapper > .right_x000D_
{_x000D_
  background: #ccf;_x000D_
  flex: 1; _x000D_
}

_x000D_

<div class="wrapper">_x000D_
  <div class="left">Left</div>_x000D_
  <div class="right">Right</div>_x000D_
</div>

_x000D_

Specify flex: 1; for both children if you want them to fill equal amounts of the horizontal space:

_x000D_

.wrapper {_x000D_
  display: flex;_x000D_
  flex-direction: row;_x000D_
  align-items: stretch;_x000D_
  width: 100%;_x000D_
  height: 5em;_x000D_
  background: #ccc;_x000D_
}_x000D_
.wrapper > div _x000D_
{_x000D_
  flex: 1; _x000D_
}_x000D_
.wrapper > .left_x000D_
{_x000D_
  background: #fcc;_x000D_
}_x000D_
.wrapper > .right_x000D_
{_x000D_
  background: #ccf;_x000D_
}

_x000D_

<div class="wrapper">_x000D_
  <div class="left">Left</div>_x000D_
  <div class="right">Right</div>_x000D_
</div>

_x000D_

AJAX cross domain call

I faced the same problem during 2 days and I found the solution, and it's elegant after googling a lot. I needed xss Ajax for some widget clients which pull datastream from tiers websites to my Rails app. here's how I did.

PreparedStatement setNull(..)

You could also consider using preparedStatement.setObject(index,value,type);

How to get base url with jquery or javascript?

window.location.origin+"/"+window.location.pathname.split('/')[1]+"/"+page+"/"+page+"_list.jsp"

almost same as Jenish answer but a little shorter.

How to bind Dataset to DataGridView in windows application

you can set the dataset to grid as follows:

//assuming your dataset object is ds

datagridview1.datasource= ds;
datagridview1.datamember= tablename.ToString();

tablename is the name of the table, which you want to show on the grid.

I hope, it helps.

B.R.

Count work days between two dates

Using a date table:

    DECLARE 
        @StartDate date = '2014-01-01',
        @EndDate date = '2014-01-31'; 
    SELECT 
        COUNT(*) As NumberOfWeekDays
    FROM dbo.Calendar
    WHERE CalendarDate BETWEEN @StartDate AND @EndDate
      AND IsWorkDay = 1;

If you don't have that, you can use a numbers table:

    DECLARE 
    @StartDate datetime = '2014-01-01',
    @EndDate datetime = '2014-01-31'; 
    SELECT 
    SUM(CASE WHEN DATEPART(dw, DATEADD(dd, Number-1, @StartDate)) BETWEEN 2 AND 6 THEN 1 ELSE 0 END) As NumberOfWeekDays
    FROM dbo.Numbers
    WHERE Number <= DATEDIFF(dd, @StartDate, @EndDate) + 1 -- Number table starts at 1, we want a 0 base

They should both be fast and it takes out the ambiguity/complexity. The first option is the best but if you don't have a calendar table you can allways create a numbers table with a CTE.

Excel doesn't update value unless I hit Enter

Found the problem and couldn't find the solution until tried this.

Open Visual Basic from Developer tab (OR right-click at any sheet and click 'View code')
At upper left panel, select 'ThisWorkbook'
At lower left panel, find 'ForceFullCalculation' attribute
Change it from 'False' to 'True' and save it

I'm not sure if this has any side-effect, but it is work for me now.

Connect HTML page with SQL server using javascript

<script>
var name=document.getElementById("name").value;
var address= document.getElementById("address").value;
var age= document.getElementById("age").value;

$.ajax({
      type:"GET",
      url:"http://hostname/projectfolder/webservicename.php?callback=jsondata&web_name="+name+"&web_address="+address+"&web_age="+age,
      crossDomain:true,
      dataType:'jsonp',
      success: function jsondata(data)
           {

            var parsedata=JSON.parse(JSON.stringify(data));
            var logindata=parsedata["Status"];

            if("sucess"==logindata)
            {   
                alert("success");
            }
            else
            {
                alert("failed");
            }
          }  
    }); 
<script>

You need to use web services. In the above code I have php web service to be used which has a callback function which is optional. Assuming you know HTML5 I did not post the html code. In the url you can send the details to the web server.

How to set auto increment primary key in PostgreSQL?

Steps to do it on PgAdmin:

CREATE SEQUENCE sequnence_title START 1; // if table exist last id
Add this sequense to the primary key, table - properties - columns - column_id(primary key) edit - Constraints - Add nextval('sequnence_title'::regclass) to the field default.

Npm Please try using this command again as root/administrator

Here is how I fixed the problem in Windows. I was trying to install the CLI for Angular.

Turn off firewall and antivirus protections.
Right click the nodejs folder (under Program Files), select Properties (scroll all the way down), click the Security tab, and click all items in the ALLOW column (for All System Packages and any user or group that allows you to add the “allow” checkmark).
Click the Windows icon. Type cmd. Right click the top result and select Run as Administrator. A command window results.
Type npm cache clean. If there is an error, close log files or anything open and rerun.
Type npm install -g @angular/cli (Or whatever npm install command you are using)
Check the installation by typing ng –version (Or whatever you need to verify your install)

Good luck! Note: If you are still having problems, check the Path in Environmental Variables. (To access: Control Panel ? System and Security ? System ? Advanced system settings ? Environment variables.) My path variable included the following: C:\Users\Michele\AppData\Roaming\npm

C# Get a control's position on a form

I usually combine PointToScreen and PointToClient:

Point locationOnForm = control.FindForm().PointToClient(
    control.Parent.PointToScreen(control.Location));

C++: what regex library should I use?

C++ has a builtin regex library since TR1. AFAIK Boost's regex library is very compatible with it and can be used as a replacement, if your standard library doesn't provide TR1.

set column width of a gridview in asp.net

Set width

HeaderStyle-width

for Example HeaderStyle-width="10%"

Convert a bitmap into a byte array

Very simple use this just in one line:

byte[] imgdata = File.ReadAllBytes(@"C:\download.png");

Android Bitmap to Base64 String

Use this code..

import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.util.Base64;
import java.io.ByteArrayOutputStream;

public class ImageUtil 
{ 
    public static Bitmap convert(String base64Str) throws IllegalArgumentException 
    { 
        byte[] decodedBytes = Base64.decode( base64Str.substring(base64Str.indexOf(",") + 1), Base64.DEFAULT );
        return BitmapFactory.decodeByteArray(decodedBytes, 0, decodedBytes.length);
    } 

    public static String convert(Bitmap bitmap) 
    { 
        ByteArrayOutputStream outputStream = new ByteArrayOutputStream();
        bitmap.compress(Bitmap.CompressFormat.PNG, 100, outputStream);
        return Base64.encodeToString(outputStream.toByteArray(), Base64.DEFAULT);
    }
}

Plugin org.apache.maven.plugins:maven-compiler-plugin or one of its dependencies could not be resolved

I also got the same issue and not able to create a jar, and I found that in Windows-->Prefernces-->Java-->installed JREs By default JRE was added to the build path of newly created java project so just changed it to your prefered JDK.

How to prevent buttons from submitting forms

You can simply get the reference of your buttons using jQuery, and prevent its propagation like below:

 $(document).ready(function () {
    $('#BUTTON_ID').click(function(e) {

            e.preventDefault();
            e.stopPropagation();
            e.stopImmediatePropagation();

            return false;
    });});

Using Service to run background and create notification

The question is relatively old, but I hope this post still might be relevant for others.

TL;DR: use AlarmManager to schedule a task, use IntentService, see the sample code here;

What this test-application(and instruction) is about:

Simple helloworld app, which sends you notification every 2 hours. Clicking on notification - opens secondary Activity in the app; deleting notification tracks.

When should you use it:

Once you need to run some task on a scheduled basis. My own case: once a day, I want to fetch new content from server, compose a notification based on the content I got and show it to user.

What to do:

First, let's create 2 activities: MainActivity, which starts notification-service and NotificationActivity, which will be started by clicking notification:

activity_main.xml

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:padding="16dp">
    <Button
        android:id="@+id/sendNotifications"
        android:onClick="onSendNotificationsButtonClick"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Start Sending Notifications Every 2 Hours!" />
</RelativeLayout>

MainActivity.java

public class MainActivity extends AppCompatActivity {
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
    }

    public void onSendNotificationsButtonClick(View view) {
        NotificationEventReceiver.setupAlarm(getApplicationContext());
    }   
}

and NotificationActivity is any random activity you can come up with. NB! Don't forget to add both activities into AndroidManifest.

Then let's create WakefulBroadcastReceiver broadcast receiver, I called NotificationEventReceiver in code above.

Here, we'll set up AlarmManager to fire PendingIntent every 2 hours (or with any other frequency), and specify the handled actions for this intent in onReceive() method. In our case - wakefully start IntentService, which we'll specify in the later steps. This IntentService would generate notifications for us.

Also, this receiver would contain some helper-methods like creating PendintIntents, which we'll use later

NB1! As I'm using WakefulBroadcastReceiver, I need to add extra-permission into my manifest: <uses-permission android:name="android.permission.WAKE_LOCK" />

NB2! I use it wakeful version of broadcast receiver, as I want to ensure, that the device does not go back to sleep during my IntentService's operation. In the hello-world it's not that important (we have no long-running operation in our service, but imagine, if you have to fetch some relatively huge files from server during this operation). Read more about Device Awake here.

NotificationEventReceiver.java

public class NotificationEventReceiver extends WakefulBroadcastReceiver {

    private static final String ACTION_START_NOTIFICATION_SERVICE = "ACTION_START_NOTIFICATION_SERVICE";
    private static final String ACTION_DELETE_NOTIFICATION = "ACTION_DELETE_NOTIFICATION";
    private static final int NOTIFICATIONS_INTERVAL_IN_HOURS = 2;

    public static void setupAlarm(Context context) {
        AlarmManager alarmManager = (AlarmManager) context.getSystemService(Context.ALARM_SERVICE);
        PendingIntent alarmIntent = getStartPendingIntent(context);
        alarmManager.setRepeating(AlarmManager.RTC_WAKEUP,
                getTriggerAt(new Date()),
                NOTIFICATIONS_INTERVAL_IN_HOURS * AlarmManager.INTERVAL_HOUR,
                alarmIntent);
    }

    @Override
    public void onReceive(Context context, Intent intent) {
        String action = intent.getAction();
        Intent serviceIntent = null;
        if (ACTION_START_NOTIFICATION_SERVICE.equals(action)) {
            Log.i(getClass().getSimpleName(), "onReceive from alarm, starting notification service");
            serviceIntent = NotificationIntentService.createIntentStartNotificationService(context);
        } else if (ACTION_DELETE_NOTIFICATION.equals(action)) {
            Log.i(getClass().getSimpleName(), "onReceive delete notification action, starting notification service to handle delete");
            serviceIntent = NotificationIntentService.createIntentDeleteNotification(context);
        }

        if (serviceIntent != null) {
            startWakefulService(context, serviceIntent);
        }
    }

    private static long getTriggerAt(Date now) {
        Calendar calendar = Calendar.getInstance();
        calendar.setTime(now);
        //calendar.add(Calendar.HOUR, NOTIFICATIONS_INTERVAL_IN_HOURS);
        return calendar.getTimeInMillis();
    }

    private static PendingIntent getStartPendingIntent(Context context) {
        Intent intent = new Intent(context, NotificationEventReceiver.class);
        intent.setAction(ACTION_START_NOTIFICATION_SERVICE);
        return PendingIntent.getBroadcast(context, 0, intent, PendingIntent.FLAG_UPDATE_CURRENT);
    }

    public static PendingIntent getDeleteIntent(Context context) {
        Intent intent = new Intent(context, NotificationEventReceiver.class);
        intent.setAction(ACTION_DELETE_NOTIFICATION);
        return PendingIntent.getBroadcast(context, 0, intent, PendingIntent.FLAG_UPDATE_CURRENT);
    }
}

Now let's create an IntentService to actually create notifications.

There, we specify onHandleIntent() which is responses on NotificationEventReceiver's intent we passed in startWakefulService method.

If it's Delete action - we can log it to our analytics, for example. If it's Start notification intent - then by using NotificationCompat.Builder we're composing new notification and showing it by NotificationManager.notify. While composing notification, we are also setting pending intents for click and remove actions. Fairly Easy.

NotificationIntentService.java

public class NotificationIntentService extends IntentService {

    private static final int NOTIFICATION_ID = 1;
    private static final String ACTION_START = "ACTION_START";
    private static final String ACTION_DELETE = "ACTION_DELETE";

    public NotificationIntentService() {
        super(NotificationIntentService.class.getSimpleName());
    }

    public static Intent createIntentStartNotificationService(Context context) {
        Intent intent = new Intent(context, NotificationIntentService.class);
        intent.setAction(ACTION_START);
        return intent;
    }

    public static Intent createIntentDeleteNotification(Context context) {
        Intent intent = new Intent(context, NotificationIntentService.class);
        intent.setAction(ACTION_DELETE);
        return intent;
    }

    @Override
    protected void onHandleIntent(Intent intent) {
        Log.d(getClass().getSimpleName(), "onHandleIntent, started handling a notification event");
        try {
            String action = intent.getAction();
            if (ACTION_START.equals(action)) {
                processStartNotification();
            }
            if (ACTION_DELETE.equals(action)) {
                processDeleteNotification(intent);
            }
        } finally {
            WakefulBroadcastReceiver.completeWakefulIntent(intent);
        }
    }

    private void processDeleteNotification(Intent intent) {
        // Log something?
    }

    private void processStartNotification() {
        // Do something. For example, fetch fresh data from backend to create a rich notification?

        final NotificationCompat.Builder builder = new NotificationCompat.Builder(this);
        builder.setContentTitle("Scheduled Notification")
                .setAutoCancel(true)
                .setColor(getResources().getColor(R.color.colorAccent))
                .setContentText("This notification has been triggered by Notification Service")
                .setSmallIcon(R.drawable.notification_icon);

        PendingIntent pendingIntent = PendingIntent.getActivity(this,
                NOTIFICATION_ID,
                new Intent(this, NotificationActivity.class),
                PendingIntent.FLAG_UPDATE_CURRENT);
        builder.setContentIntent(pendingIntent);
        builder.setDeleteIntent(NotificationEventReceiver.getDeleteIntent(this));

        final NotificationManager manager = (NotificationManager) this.getSystemService(Context.NOTIFICATION_SERVICE);
        manager.notify(NOTIFICATION_ID, builder.build());
    }
}

Almost done. Now I also add broadcast receiver for BOOT_COMPLETED, TIMEZONE_CHANGED, and TIME_SET events to re-setup my AlarmManager, once device has been rebooted or timezone has changed (For example, user flown from USA to Europe and you don't want notification to pop up in the middle of the night, but was sticky to the local time :-) ).

NotificationServiceStarterReceiver.java
```
public final class NotificationServiceStarterReceiver extends BroadcastReceiver {

    @Override
    public void onReceive(Context context, Intent intent) {
        NotificationEventReceiver.setupAlarm(context);
    }
}
```

We need to also register all our services, broadcast receivers in AndroidManifest:

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="klogi.com.notificationbyschedule">

    <uses-permission android:name="android.permission.INTERNET" />
    <uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" />
    <uses-permission android:name="android.permission.RECEIVE_BOOT_COMPLETED" />
    <uses-permission android:name="android.permission.WAKE_LOCK" />

    <application
        android:allowBackup="true"
        android:icon="@mipmap/ic_launcher"
        android:label="@string/app_name"
        android:supportsRtl="true"
        android:theme="@style/AppTheme">
        <activity android:name=".MainActivity">
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />

                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>

        <service
            android:name=".notifications.NotificationIntentService"
            android:enabled="true"
            android:exported="false" />

        <receiver android:name=".broadcast_receivers.NotificationEventReceiver" />
        <receiver android:name=".broadcast_receivers.NotificationServiceStarterReceiver">
            <intent-filter>
                <action android:name="android.intent.action.BOOT_COMPLETED" />
                <action android:name="android.intent.action.TIMEZONE_CHANGED" />
                <action android:name="android.intent.action.TIME_SET" />
            </intent-filter>
        </receiver>

        <activity
            android:name=".NotificationActivity"
            android:label="@string/title_activity_notification"
            android:theme="@style/AppTheme.NoActionBar"/>
    </application>

</manifest>

That's it!

The source code for this project you can find here. I hope, you will find this post helpful.

Port 443 in use by "Unable to open process" with PID 4

Similarly, I experienced this: Port 443 in use by "Unable to open process" with PID 6012! When starting XAMPP Control Panel v3.2.1 for the first time.

In Task Manager I found that PID 6012 was Apache web server. A copy of it was running in the background without the GUI, and when I invoked the GUI it was trying to start another copy. Killed the phantom copy and then XAMPP started up fine.

I didn't have to change any port settings.

Python != operation vs "is not"

First, let me go over a few terms. If you just want your question answered, scroll down to "Answering your question".

Definitions

Object identity: When you create an object, you can assign it to a variable. You can then also assign it to another variable. And another.

>>> button = Button()
>>> cancel = button
>>> close = button
>>> dismiss = button
>>> print(cancel is close)
True

In this case, cancel, close, and dismiss all refer to the same object in memory. You only created one Button object, and all three variables refer to this one object. We say that cancel, close, and dismiss all refer to identical objects; that is, they refer to one single object.

Object equality: When you compare two objects, you usually don't care that it refers to the exact same object in memory. With object equality, you can define your own rules for how two objects compare. When you write if a == b:, you are essentially saying if a.__eq__(b):. This lets you define a __eq__ method on a so that you can use your own comparison logic.

Rationale for equality comparisons

Rationale: Two objects have the exact same data, but are not identical. (They are not the same object in memory.) Example: Strings

>>> greeting = "It's a beautiful day in the neighbourhood."
>>> a = unicode(greeting)
>>> b = unicode(greeting)
>>> a is b
False
>>> a == b
True

Note: I use unicode strings here because Python is smart enough to reuse regular strings without creating new ones in memory.

Here, I have two unicode strings, a and b. They have the exact same content, but they are not the same object in memory. However, when we compare them, we want them to compare equal. What's happening here is that the unicode object has implemented the __eq__ method.

class unicode(object):
    # ...

    def __eq__(self, other):
        if len(self) != len(other):
            return False

        for i, j in zip(self, other):
            if i != j:
                return False

        return True

Note: __eq__ on unicode is definitely implemented more efficiently than this.

Rationale: Two objects have different data, but are considered the same object if some key data is the same. Example: Most types of model data

>>> import datetime
>>> a = Monitor()
>>> a.make = "Dell"
>>> a.model = "E770s"
>>> a.owner = "Bob Jones"
>>> a.warranty_expiration = datetime.date(2030, 12, 31)
>>> b = Monitor()
>>> b.make = "Dell"
>>> b.model = "E770s"
>>> b.owner = "Sam Johnson"
>>> b.warranty_expiration = datetime.date(2005, 8, 22)
>>> a is b
False
>>> a == b
True

Here, I have two Dell monitors, a and b. They have the same make and model. However, they neither have the same data nor are the same object in memory. However, when we compare them, we want them to compare equal. What's happening here is that the Monitor object implemented the __eq__ method.

class Monitor(object):
    # ...

    def __eq__(self, other):
        return self.make == other.make and self.model == other.model

Answering your question

When comparing to None, always use is not. None is a singleton in Python - there is only ever one instance of it in memory.

By comparing identity, this can be performed very quickly. Python checks whether the object you're referring to has the same memory address as the global None object - a very, very fast comparison of two numbers.

By comparing equality, Python has to look up whether your object has an __eq__ method. If it does not, it examines each superclass looking for an __eq__ method. If it finds one, Python calls it. This is especially bad if the __eq__ method is slow and doesn't immediately return when it notices that the other object is None.

Did you not implement __eq__? Then Python will probably find the __eq__ method on object and use that instead - which just checks for object identity anyway.

When comparing most other things in Python, you will be using !=.

Set padding for UITextField with UITextBorderStyleNone

Swift 2.0 Version:

let paddingView: UIView = UIView(frame: CGRectMake(0, 0, 5, 20))
textField.leftView = paddingView
textField.leftViewMode = UITextFieldViewMode.Always;

Android update activity UI from service

Clyde's solution works, but it is a broadcast, which I am pretty sure will be less efficient than calling a method directly. I could be mistaken, but I think the broadcasts are meant more for inter-application communication.

I'm assuming you already know how to bind a service with an Activity. I do something sort of like the code below to handle this kind of problem:

class MyService extends Service {
    MyFragment mMyFragment = null;
    MyFragment mMyOtherFragment = null;

    private void networkLoop() {
        ...

        //received new data for list.
        if(myFragment != null)
            myFragment.updateList();
        }

        ...

        //received new data for textView
        if(myFragment !=null)
            myFragment.updateText();

        ...

        //received new data for textView
        if(myOtherFragment !=null)
            myOtherFragment.updateSomething();

        ...
    }
}


class MyFragment extends Fragment {

    public void onResume() {
        super.onResume()
        //Assuming your activity bound to your service
        getActivity().mMyService.mMyFragment=this;
    }

    public void onPause() {
        super.onPause()
        //Assuming your activity bound to your service
        getActivity().mMyService.mMyFragment=null;
    }

    public void updateList() {
        runOnUiThread(new Runnable() {
            public void run() {
                //Update the list.
            }
        });
    }

    public void updateText() {
       //as above
    }
}

class MyOtherFragment extends Fragment {
             public void onResume() {
        super.onResume()
        //Assuming your activity bound to your service
        getActivity().mMyService.mMyOtherFragment=this;
    }

    public void onPause() {
        super.onPause()
        //Assuming your activity bound to your service
        getActivity().mMyService.mMyOtherFragment=null;
    }

    public void updateSomething() {//etc... }
}

I left out bits for thread safety, which is essential. Make sure to use locks or something like that when checking and using or changing the fragment references on the service.

ORA-12560: TNS:protocol adaptor error

Flow the flowing steps :

Edit your listener.ora and tnsnames.ora file in $Oracle_home\product\11.2.0\client_1\NETWORK\ADMIN location

a. add listener.ora file

LISTENER =
  (DESCRIPTION_LIST =
    (DESCRIPTION =
      (ADDRESS = (PROTOCOL = IPC)(KEY = EXTPROC1521))
      (ADDRESS = (PROTOCOL = TCP)(HOST = 127.0.0.1)(PORT = 1521))
)

)

ADR_BASE_LISTENER = C: [here c is oralce home directory]

b. add in tnsnames.ora file

    SCHEMADEV =
            (DESCRIPTION =
                     (ADDRESS_LIST =
                     (ADDRESS = (PROTOCOL = TCP)(HOST = dabase_ip)(PORT = 1521))
    )
    (CONNECT_DATA =
      (SERVICE_NAME = SCHEMADEV)
    )
  )

Open command prompt and type
sqlplus username/passowrd@oracle_connection_alias

Example :
username : your_database_username
password : Your_database_password
oracle_connection_alias : SCHEMADEV for above example.

HTTP could not register URL http://+:8000/HelloWCF/. Your process does not have access rights to this namespace

I closed Visual studio IDE and reopened it by right clicking on the Visual Studio icon and saying "Run as Administrator", Then when I ran the host , It worked!!!

Create a git patch from the uncommitted changes in the current working directory

We could also specify the files, to include just the files with relative changes, particularly when they span multiple directories e.x.

git diff ~/path1/file1.ext ~/path2/file2.ext...fileN.ext > ~/whatever_path/whatever_name.patch

I found this to be not specified in the answers or comments, which are all relevant and correct, so chose to add it. Explicit is better than implicit!

Two column div layout with fluid left and fixed right column

_x000D_

#wrapper {_x000D_
  margin-right: 50%;_x000D_
}_x000D_
#content {_x000D_
  float: left;_x000D_
  width: 50%;_x000D_
  background-color: #CCF;_x000D_
}_x000D_
#sidebar {_x000D_
  float: right;_x000D_
  width: 200px;_x000D_
  margin-right: -200px;_x000D_
  background-color: #FFA;_x000D_
}_x000D_
#cleared {_x000D_
  clear: both;_x000D_
}

_x000D_

<div id="wrapper">_x000D_
  <div id="content">Column 1 (fluid)</div>_x000D_
  <div id="sidebar">Column 2 (fixed)</div>_x000D_
  <div id="cleared"></div>_x000D_
</div>

_x000D_

Programs & Examples On #Iphone wax

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Redirecting to a certain route based on condition

jQuery get content between <div> tags

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Missing XML comment for publicly visible type or member

#1142 - SELECT command denied to user ''@'localhost' for table 'pma_table_uiprefs'

Git: copy all files in a directory from another branch

If greater than batch files

How to use the start command in a batch file?

'NoneType' object is not subscriptable?

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Launch Failed Binary not found Eclipse for C in Windows

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What's the difference between import java.util.*; and import java.util.Date; ?

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What's the use of "enum" in Java?

The int enum pattern

Use enum type

Sort a two dimensional array based on one column

Shell script to get the process ID on Linux

Path to MSBuild

fatal: Unable to create temporary file '/home/username/git/myrepo.git/./objects/pack/tmp_pack_XXXXXX': Permission denied

How to recover the deleted files using "rm -R" command in linux server?

How to update fields in a model without creating a new record in django?

Dynamic Height Issue for UITableView Cells (Swift)

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Why does LayoutInflater ignore the layout_width and layout_height layout parameters I've specified?

How can I stage and commit all files, including newly added files, using a single command?

Pointtype command for gnuplot

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why I can't get value of label with jquery and javascript?

Reading a json file in Android

convert string date to java.sql.Date

Assign a class name to <img> tag instead of write it in css file?

Django URL Redirect

Getting the parameters of a running JVM

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Set focus to field in dynamically loaded DIV

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Oracle: what is the situation to use RAISE_APPLICATION_ERROR?

QUERY syntax using cell reference

Difference between webdriver.get() and webdriver.navigate()

get()

navigate()

How do I get the XML root node with C#?

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How to reload a page using Angularjs?

Ruby on Rails: Where to define global constants?

Equivalent of waitForVisible/waitForElementPresent in Selenium WebDriver tests using Java?

Implicit and Explicit Waits

How to convert a set to a list in python?

A completely free agile software process tool

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What are some ways of accessing Microsoft SQL Server from Linux?

How to write connection string in web.config file and read from it?

Defining static const integer members in class definition

How to Edit a row in the datatable

How to debug Spring Boot application with Eclipse?

How to debug a remote staging or production Spring Boot application

Use `enum` type