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Def: Final Keyword prevents child classes from overriding a method by prefixing the definition with final. If the class itself is being defined final then it cannot be extended Final Method class BaseClass { public function test() { echo "BaseClass::test() called\n"; } ...

The @ sign binds a variable to a name during a pattern match. The bound variable can either be the entire matched object or part of the matched object: sealed trait Shape case class Rectangle(height: Int, width: Int) extends Shape case class Circle(radius: Int) extends Shape case object Point ex...

Pattern matching can also be used to check the type of an instance, rather than using isInstanceOf[B]: val anyRef: AnyRef = "" anyRef match { case _: Number => "It is a number" case _: String => "I...

This operator checks whether the object is of a particular class/interface type. instanceof operator is written as: ( Object reference variable ) instanceof (class/interface type) Example: public class Test { public static void main(String args[]){ String name = "Buyya";...

Lazy evaluation means Haskell will evaluate only list items whose values are needed. The basic recursive definition is: f (0) <- 0 f (1) <- 1 f (n) <- f (n-1) + f (n-2) If evaluated directly, it will be very slow. But, imagine we have a list that records all the results, fibs ...

There is no simple way to obtain attributes from an interface, since classes does not inherit attributes from an interface. Whenever implementing an interface or overriding members in a derived class, you need to re-declare the attributes. So in the example below output would be True in all three c...

To take a photo, first we need to declare required permissions in AndroidManifest.xml. We need two permissions: Camera - to open camera app. If attribute required is set to true you will not be able to install this app if you don't have hardware camera. WRITE_EXTERNAL_STORAGE - This permission i...

The first thing we need to do it add EventBus to our module's gradle file: dependencies { ... compile 'org.greenrobot:eventbus:3.0.0' ... } Now we need to create a model for our event. It can contain anything we want to pass along. For now we'll just make an empty class. public ...

You will have to inject $filter: angular .module('filters', []) .filter('percentage', function($filter) { return function (input) { return $filter('number')(input * 100) + ' %'; }; });

ng-include allows you to delegate the control of one part of the page to a specific controller. You may want to do this because the complexity of that component is becoming such that you want to encapsulate all the logic in a dedicated controller. An example is: <div ng-include src=&q...

Use Conditionals via (syntax is in [brackets]): when [when:] Task: - name: run if operating system is debian command: echo "I am a Debian Computer" when: ansible_os_family == "Debian" loops [with_items:] loops [with_dicts:] Custom Facts [ wh...

- name: copy ssl key/cert/ssl_include files copy: src=files/ssl/{{ item }} dest=/etc/apache2/ssl/ with_items: - g_chain.crt - server.crt - server.key - ssl_vhost.inc

Ordering the results and setting a limit can easily be achieved with 2 additional lines added to the chain, like so: $db = JFactory::getDbo(); $query = $db->getQuery(true); $query->select('*') ->from('#__users') ->where('username = '. $db->q('John')) ->ord...

Directives can be used to build reusable components. Here is an example of a "user box" component: userBox.js angular.module('simpleDirective', []).directive('userBox', function() { return { scope: { username: '=username', reputation: '=reputation' }, ...

Preliminary Install the Cordova cli tools, if you haven't already. $ npm install -g cordova Navigate to your desired working folder. $ cd /path/to/coding/folder Creating the application Create a new application $ cordova create <appProjectName> <appNameSpace> <appName> For ...

iText for Java Importing the iText jars from the Central Maven Repository is the best way to install iText 7. These simple videos explain how to do this using different IDEs: How to import iText 7 in Eclipse to create a Hello World PDF? How to import iText 7 in Netbeans to create a Hello World ...

Behaviours are a list of functions specifications that another module can implement. They are similar to interfaces in other languages. Here’s an example behaviour: defmodule Parser do @callback parse(String.t) :: any @callback extensions() :: [String.t] end And a module that implements ...

POSIX/IEEE Open Group Base Specification says: [2addr] s/BRE/replacement/flags Substitute the replacement string for instances of the BRE in the pattern space. Any character other than backslash or newline can be used instead of a slash to delimit the BRE and the replacement. Within the BRE a...

Types can represents various kind of things. It can be a single data, a set of data or a function. In F#, we can group the types into two categories.: F# types: // Functions let a = fun c -> c // Tuples let b = (0, "Foo") // Unit type let c = ignore // Records...

Encapsulation is a basic concept in OOP. It is about wrapping data and code as a single unit. In this case, it is a good practice to declare the variables as private and then access them through Getters and Setters to view and/or modify them. public class Sample { private String name; privat...