Yii2源码学习之yii\base\Behavior代码详解-蒲公英云

<?php
/**
 * @link http://www.yiiframework.com/
 * @copyright Copyright (c) 2008 Yii Software LLC
 * @license http://www.yiiframework.com/license/
 */
namespace yii\base;
/**
 * Behavior is the base class for all behavior classes.
 * 所有行为的基类
 *
 * A behavior can be used to enhance the functionality of an existing component without modifying its code.
 * In particular, it can "inject" its own methods and properties into the component
 * and make them directly accessible via the component. It can also respond to the events triggered in the component
 * and thus intercept the normal code execution.
 * 用来增强现有组件的功能而不修改它的代码。它可以添加自己的方法和属性组件
 * 使他们可以直接通过组件访问。还可以响应组件中触发的事件，拦截正常的代码执行。
 *
 * @author Qiang Xue <qiang.xue@gmail.com>
 * @since 2.0
 *
 * 继承父类Object
 */
class Behavior extends Object
{
    /**
     * @var Component the owner of this behavior
     * 行为组件的所有者,要附加行为对象的组件。
     */
    public $owner;
    /**
     * Declares event handlers for the [[owner]]'s events.
     * 声明[[owner]]的事件处理程序
     *
     * Child classes may override this method to declare what PHP callbacks should
     * be attached to the events of the [[owner]] component.
     * 子类可以重写此方法 php回调应连接 [[owner]]组件。
     *
     * The callbacks will be attached to the [[owner]]'s events when the behavior is
     * attached to the owner; and they will be detached from the events when
     * the behavior is detached from the component.
     * 当行为被连接到owner时回调将附在[[owner]]的事件中，当行为从组件中分离时，它们将被分离
     *
     * The callbacks can be any of the following:
     *
     * - method in this behavior: `'handleClick'`, equivalent to `[$this, 'handleClick']`
     * - object method: `[$object, 'handleClick']`
     * - static method: `['Page', 'handleClick']`
     * - anonymous function: `function ($event) { ... }`
     *
     * The following is an example:
     * 下面是一个例子
     *
     * ```php
     * [
     *     Model::EVENT_BEFORE_VALIDATE => 'myBeforeValidate',
     *     Model::EVENT_AFTER_VALIDATE => 'myAfterValidate',
     * ]
     * ```
     *
     * @return array events (array keys) and the corresponding event handler methods (array values).
     * 事件和相应的事件处理方法
     */
    public function events()
    {
        // Behavior 基类本身没用，主要是子类使用，重载这个函数返回一个数组表
        // 示行为所关联的事件
        //用于表示行为所有要响应的事件
        return [];
    }
    /**
     * Attaches the behavior object to the component. 绑定行为到组件
     * The default implementation will set the [[owner]] property
     * and attach event handlers as declared in [[events]].
     * 默认设置[[owner]]属性并将事件处理程序绑定到组件
     * Make sure you call the parent implementation if you override this method. 如果重写方法，确保调用父类去实现
     * @param Component $owner the component that this behavior is to be attached to. 行为绑定到$owner组件
     */
    public function attach($owner)
    {
        $this->owner = $owner;//设置 $owner ，使得所依附的对象可以访问、操作
        foreach ($this->events() as $event => $handler) {
            //将准备响应的事件，通过所依附类的 on()方法 绑定到类上
            $owner->on($event, is_string($handler) ? [$this, $handler] : $handler);
        }
    }
    /**
     * Detaches the behavior object from the component. 解除绑定的行为
     * The default implementation will unset the [[owner]] property  默认取消 owner的属性
     * and detach event handlers declared in [[events]]. 将events中的事件程序解除绑定
     * Make sure you call the parent implementation if you override this method. 如果重写方法，确保调用父类去实现
     */
    public function detach()
    {
        if ($this->owner) {
            foreach ($this->events() as $event => $handler) {
   //遍历行为中 events() 返回的数组
                //通过Component的 off() 将绑定到类上的事件解除
                $this->owner->off($event, is_string($handler) ? [$this, $handler] : $handler);
            }
            $this->owner = null;//将 $owner 设置为 null ，表示这个解除绑定
        }
    }
}
/*
 * 一个绑定了行为的类，表现起来是这样的:
 *
 */
// Step 1: 定义一个将绑定行为的类
// class MyClass extends yii\base\Component
//  {
    // 空的
// }
// Step 2: 定义一个行为类，他将绑定到MyClass上
// class MyBehavior extends yii\base\Behavior
//{
    // 行为的一个属性
//    public $property1 = 'This is property in MyBehavior.';
    // 行为的一个方法
//    public function method1()
//    {
//        return 'Method in MyBehavior is called.';
//    }
// }
//$myClass = new MyClass();
//$myBehavior = new MyBehavior();
// Step 3: 将行为绑定到类上
//$myClass->attachBehavior('myBehavior', $myBehavior);
// Step 4: 访问行为中的属性和方法，就和访问类自身的属性和方法一样
//echo $myClass->property1;
//echo $myClass->method1();