Tutorial by Examples: class

Implementations in classes, including abstract declarations, take precedence over all interface defaults. Abstract class method takes precedence over Interface Default Method. public interface Swim { default void backStroke() { System.out.println("Swim.backStroke"); ...
Firstly, make sure that the agent being used has the following attributes in the Manifest.mf: Can-Redefine-Classes: true Can-Retransform-Classes: true Starting a java agent will let the agent access the class Instrumentation. With Instrumentation you can call addTransformer(ClassFileTransformer...
It's a very common extension that allows type classes with multiple type parameters. You can think of MPTC as a relation between types. {-# LANGUAGE MultiParamTypeClasses #-} class Convertable a b where convert :: a -> b instance Convertable Int Float where convert i = fromIntegr...
When creating a SOAP Client in PHP, you can also set a classmap key in the configuration array. This classmap defines which types defined in the WSDL should be mapped to actual classes, instead of the default StdClass. The reason you would want to do this is because you can get auto-completion of fi...
Header file UIColor+XYZPalette.h: @interface UIColor (XYZPalette) +(UIColor *)xyz_indigoColor; @end and implementation UIColor+XYZPalette.m: @implementation UIColor (XYZPalette) +(UIColor *)xyz_indigoColor { return [UIColor colorWithRed:75/255.0f green:0/255.0f blue:130/255.0f al...
You can restrict the valid types used in a generic class by bounding that type in the class definition. Given the following simple type hierarchy: public abstract class Animal { public abstract String getSound(); } public class Cat extends Animal { public String getSound() { ...
Subclassing UIControl gives us access to the following methods: beginTrackingWithTouch is called when the finger first touches down within the control's bounds. continueTrackingWithTouch is called repeatedly as the finger slides across the control and even outside of the control's bounds. endTr...
import { Http, Request, RequestOptionsArgs, Response, RequestOptions, ConnectionBackend, Headers } from '@angular/http'; import { Router } from '@angular/router'; import { Observable } from 'rxjs/Observable'; import 'rxjs/add/observable/empty'; import 'rxjs/add/observable/throw'; import 'rxjs/a...
After extending the Http class, we need to tell angular to use this class instead of Http class. In order to do this, in our main module(or depending on the needs, just a particular module), we need to write in the providers section: export function httpServiceFactory(xhrBackend: XHRBackend, reque...
__CLASS__ magic constant returns the same result as get_class() function called without parameters and they both return the name of the class where it was defined (i.e. where you wrote the function call/constant name ). In contrast, get_class($this) and get_called_class() functions call, will both ...
Type hinting for classes and interfaces was added in PHP 5. Class type hint <?php class Student { public $name = 'Chris'; } class School { public $name = 'University of Edinburgh'; } function enroll(Student $student, School $school) { echo $student->name . ' is b...
A class method is called on the class the method belongs to, not an instance of it. This is possible because Objective-C classes are also objects. To denote a method as a class method, change the - to a +: + (void)hello { NSLog(@"Hello World"); }
Abstract classes are classes that are meant to be inherited but avoid implementing specific methods, leaving behind only method signatures that subclasses must implement. Abstract classes are useful for defining and enforcing class abstractions at a high level, similar to the concept of interfaces ...
Enumerable is the most popular module in Ruby. Its purpose is to provide you with iterable methods like map, select, reduce, etc. Classes that use Enumerable include Array, Hash, Range. To use it, you have to include Enumerable and implement each. class NaturalNumbers include Enumerable de...
Private inheritance is useful when it is required to restrict the public interface of the class: class A { public: int move(); int turn(); }; class B : private A { public: using A::turn; }; B b; b.move(); // compile error b.turn(); // OK This approach efficiently pr...
If you have an existing class that you'd like to use, perform Step 2 and then skip to Step 5. (For some cases, I had to add an explicit #import <Foundation/Foundation.h to an older ObjC File) Step 1: Add Objective-C Implementation -- .m Add a .m file to your class, and name it CustomObje...
Step 1: Create New Swift Class Add a .swift file to your project, and name it MySwiftObject.swift In MySwiftObject.swift: import Foundation class MySwiftObject : NSObject { var someProperty: AnyObject = "Some Initializer Val" init() {} func someFunction(someArg...
Classes can be created as follow: class InputField { int maxLength; String name; } The class can be instantiated using the new keyword after which the field values will be null by default. var field = new InputField(); Field values can then be accessed: // this will trigger the sette...
<?php namespace models; use yii\db\ActiveRecord; use yii\behaviors\TimestampBehavior; class Post extends ActiveRecord { public static function tableName() { return 'post'; } public function rules() { ...
Class methods present alternate ways to build instances of classes. To illustrate, let's look at an example. Let's suppose we have a relatively simple Person class: class Person(object): def __init__(self, first_name, last_name, age): self.first_name = first_name self.last...

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