<?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. * * 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. * * @author Qiang Xue <qiang.xue@gmail.com> * @since 2.0 */ class Behavior extends \yii\base\Object { /** * @var Component the owner of this behavior */ public $owner; /** * Declares event handlers for the [[owner]]'s events. * * Child classes may override this method to declare what PHP callbacks should * be attached to the events of the [[owner]] component. * * The callbacks will be attached to the [[owner]]'s events when the behavior is * attached to the owner; and they will be detached from the events when * the behavior is detached from the component. * * The callbacks can be any of the followings: * * - method in this behavior: `'handleClick'`, equivalent to `[$this, 'handleClick']` * - object method: `[$object, 'handleClick']` * - static method: `['Page', 'handleClick']` * - anonymous function: `function($event) { ... }` * * The following is an example: * * ~~~ * [ * Model::EVENT_BEFORE_VALIDATE => 'myBeforeValidate', * Model::EVENT_AFTER_VALIDATE => 'myAfterValidate', * ] * ~~~ * * @return array events (array keys) and the corresponding event handler methods (array values). */ public function events() { return []; } /** * Attaches the behavior object to the component. * The default implementation will set the [[owner]] property * and attach event handlers as declared in [[events]]. * Make sure you call the parent implementation if you override this method. * @param Component $owner the component that this behavior is to be attached to. */ public function attach($owner) { $this->owner = $owner; foreach ($this->events() as $event => $handler) { $owner->on($event, is_string($handler) ? [$this, $handler] : $handler); } } /** * Detaches the behavior object from the component. * The default implementation will unset the [[owner]] property * and detach event handlers declared in [[events]]. * Make sure you call the parent implementation if you override this method. */ public function detach() { if ($this->owner) { foreach ($this->events() as $event => $handler) { $this->owner->off($event, is_string($handler) ? [$this, $handler] : $handler); } $this->owner = null; } } }