Tutorial by Examples: at

This example shows a helper class that contains methods useful, when executing the queries for data. Every method here uses Java Generic's in order to be very flexible. public <T> List<T> selectElements(AbstractDao<T, ?> dao) { if (dao == null) { return null; } ...

This technique details how to ensure that your .apk has been signed with your developer certificate, and leverages the fact that the certificate remains consistent and that only you have access to it. We can break this technique into 3 simple steps: Find your developer certificate signature. Em...

q = Queue.new q << "any object including another queue" # or q.push :data There is no high water mark, queues can infinitely grow. #push never blocks

q = Queue.new q << :data q.pop #=> :data #pop will block until there is some data available. #pop can be used for synchronization.

syncer = Queue.new a = Thread.new do syncer.pop puts "this happens at end" end b = Thread.new do puts "this happens first" STDOUT.flush syncer << :ok end [a, b].map(&:join)

Enum constructors can be matched using pattern matching. Assume the following enum: enum Color { Red; Green; Blue; RGB(r : Int, g : Int, b : Int); } Colours with only a green channel value can be matched as follows: var color = Color.RGB(0, 127, 0); var isGreenOnly = swit...

Operator overloading is only possible with abstract types. The following abstract defines a Vec2i type based on the Array<Int> type. This is a two-component vector with integer values. Operator overloading is made possible my the @:op compiler metadata. Only the available numeric operators ca...

In Groovy, the inject() method is one of the cumulative methods that allows us to add (or inject) new functionality into any object that implements the inject() method. In the case of a Collection, we can apply a closure to a collection of objects uniformly and then collate the results into a single...

SilverStripe has reasonably good support for submitting form data using AJAX requests. Below is example code of how to set up a basic Form that accepts submissions by both AJAX and traditional default browser behaviour (as is good practice). Adding the form to our controller First we need to defin...

The following class is used to demonstrate, how instances of classes can be created: JavaFX 8 The annotation in Person(@NamedArg("name") String name) has to be removed, since the @NamedArg annotation is unavailable. package fxml.sample; import javafx.beans.NamedArg; import javafx....

public String getAppVersion() throws PackageManager.NameNotFoundException { PackageManager manager = getApplicationContext().getPackageManager(); PackageInfo info = manager.getPackageInfo( getApplicationContext().getPackageName(), ...

You should use this when you have two text fields that should receive exactly the same content. For example, you may want to confirm an email address or a password. This validation creates a virtual attribute whose name is the name of the field that has to be confirmed with _confirmation appended. ...

UIView *view = [[UIView alloc] init]; [self.view addSubview:view]; //Use the function if you want to use height as constraint [self addView:view onParentView:self.view withHeight:200.f]; //Use this function if you want to add view with respect to parent and should resize with it [self a...

Angular Forms and Inputs have various states that are useful when validating content Input States StateDescription$touchedField has been touched$untouchedField has not been touched$pristineField has not been modified$dirtyField has been modified$validField content is valid$invalidField content is ...

A StringBuilder represents a series of characters, which unlike a normal string, are mutable. Often times there is a need to modify strings that we've already made, but the standard string object is not mutable. This means that each time a string is modified, a new string object needs to be created,...

You can configure the database settings in config/connections.js. Here's an example: postgresql: { database: 'databaseName', host: 'localhost', user: 'root', password: '', port: 5432, poolSize: 10, ssl: false }; Alternatively, you can supply the connection information in U...

Short circuiting is a functionality that skips evaluating parts of a (if/while/...) condition when able. In case of a logical operation on two operands, the first operand is evaluated (to true or false) and if there is a verdict (i.e first operand is false when using &&, first operand is tr...

OSX Implement the contract of the role-specific protocol (NSAccessibilityButton, NSAccessibilityImage, NSAccessibilityGroup, etc) within the NSAccessibility protocol that best matches the behavior of the GUI element being rendered. Linux / BSD For GNOME applications, the GNOME Accessibility Impl...

The most common way is to apply the extension via Config. Example: # File: mysite/_config/config.yml Member: extensions: - MyMemberExtension The extensions config variable is of type "array", so you can add multiple extensions like this: # File: mysite/_config/config.yml Mem...

library(gpuR) # gpuMatrix objects X <- gpuMatrix(rnorm(100), 10, 10) Y <- gpuMatrix(rnorm(100), 10, 10) # transfer data to GPU when operation called # automatically copied back to CPU Z <- X %*% Y