Tutorial by Examples: b

Consider the following block of code. try { using (var disposable = new MyDisposable()) { throw new Exception("Couldn't perform operation."); } } catch (Exception ex) { Console.WriteLine(ex.Message); } class MyDisposable : IDisposable { public vo...

int a; std::cout << a; // Undefined behavior! This results in undefined behavior, because a is uninitialised. It is often, incorrectly, claimed that this is because the value is "indeterminate", or "whatever value was in that memory location before". However, it is th...

The keyword auto provides the auto-deduction of type of a variable. It is especially convenient when dealing with long type names: std::map< std::string, std::shared_ptr< Widget > > table; // C++98 std::map< std::string, std::shared_ptr< Widget > >::iterator i = table.fin...

Prerequisites In order to run Elasticsearch, a Java Runtime Environment (JRE) is required on the machine. Elasticsearch requires Java 7 or higher and recommends Oracle JDK version 1.8.0_73. Install Oracle Java 8 sudo add-apt-repository -y ppa:webupd8team/java sudo apt-get update echo "or...

The Locals window provides easy access to the current value of variables and objects within the scope of the function or subroutine you are running. It is an essential tool to debugging your code and stepping through changes in order to find issues. It also allows you to explore properties you might...

CREATE TABLE person ( person_id BIGINT NOT NULL, last_name VARCHAR(255) NOT NULL, first_name VARCHAR(255), address VARCHAR(255), city VARCHAR(255), PRIMARY KEY (person_id) ); Alternatively, you can place the PRIMARY KEY constraint directly in the column definition: ...

In ASP.NET Web API, a controller is a class that handles HTTP requests. The public methods of the controller are called action methods or simply actions. When the Web API framework receives a request, it routes the request to an action. To determine which action to invoke, the framework uses a rou...

A template autorun may be used to (re)subscribe to a publication. It establishes a reactive context which is re-executed whenever any reactive data it depends on changes. In addition, an autorun always runs once (the first time it is executed). Template autoruns are normally put in an onCreated met...

A metatable defines a set of operations which alter the behaviour of a lua object. A metatable is just an ordinary table, which is used in a special way. local meta = { } -- create a table for use as metatable -- a metatable can change the behaviour of many things -- here we modify the 'tostrin...

Some metamethods don't have to be functions. To most important example for this is the __index metamethod. It can also be a table, which is then used as lookup. This is quite commonly used in the creation of classes in lua. Here, a table (often the metatable itself) is used to hold all the operation...

5.2 Objects in lua are garbage collected. Sometimes, you need to free some resource, want to print a message or do something else when an object is destroyed (collected). For this, you can use the __gc metamethod, which gets called with the object as argument when the object is destroyed. You could...

There is a metamethod called __call, which defines the bevahiour of the object upon being used as a function, e.g. object(). This can be used to create function objects: -- create the metatable with a __call metamethod local meta = { __call = function(self) self.i = self.i + 1 e...

Perhaps the most important use of metatables is the possibility to change the indexing of tables. For this, there are two actions to consider: reading the content and writing the content of the table. Note that both actions are only triggered if the corresponding key is not present in the table. Re...

Sometimes, you don't want to trigger metamethods, but really write or read exactly the given key, without some clever functions wrapped around the access. For this, lua provides you with raw table access methods: -- first, set up a metatable that allows no read/write access local meta = { __i...

To create a background session // Swift: let mySessionID = "com.example.bgSession" let bgSessionConfig = NSURLSessionConfiguration.backgroundSessionConfigurationWithIdentifier(mySessionID) let session = NSURLSession(configuration: bgSessionConfig) // add tasks here //...

In C# 5.0 and earlier the developer could only suppress warnings by number. With the introduction of Roslyn Analyzers, C# needs a way to disable warnings issued from specific libraries. With C# 6.0 the pragma directive can suppress warnings by name. Before: #pragma warning disable 0501 C# 6.0: ...

import javax.swing.JButton; import javax.swing.JFrame; import javax.swing.JLabel; import javax.swing.JPanel; import javax.swing.SwingUtilities; import javax.swing.WindowConstants; /** * A very simple Swing example. */ public class SwingExample { /** * The number of times the ...

You can create a new branch and switch to it using git checkout -b AP-57 After you use git checkout to create a new branch, you will need to set that upstream origin to push to using git push --set-upstream origin AP-57 After that, you can use git push while you are on that branch.

3D transforms can be use to create many 3D shapes. Here is a simple 3D CSS cube example: HTML: <div class="cube"> <div class="cubeFace"></div> <div class="cubeFace face2"></div> </div> CSS: body { perspective-origin: 5...

To get template item by template Id. TemplateItem templateItem = Sitecore.Context.Database.GetTemplate(new ID("{11111111-1111-1111-1111-111111111111}"));