PHP中如何通过实例分析实现事件驱动机制？

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php事件@edit http://www.lai18.com@author xiezhenye @gmail.com

class Event{ private $callbacks=array(); private $holder;

function __construct() { $bt=debug_backtrace(); if (count($bt) > 2) { $this->holder=null; } }}

<?php /** * 事件 * @edit www.lai18.com * @author xiezhenye <xiezhenye@gmail.com> */ class Event { private $callbacks = array(); private $holder; function __construct() { $bt = debug_backtrace(); if (count($bt) < 2) { $this->holder = null; return; } $this->holder = &$bt[1]['object']; } function attach() { $args = func_get_args(); switch (count($args)) { case 1: if (is_callable($args[0])) { $this->callbacks[]= $args[0]; return; } break; case 2: if (is_object($args[0]) && is_string($args[1])) { $this->callbacks[]= array(&$args[0], $args[1]); } return; default: return; } } function notify() { $bt = debug_backtrace(); if ($this->holder && ((count($bt) >= 2 && $bt[count($bt) - 1]['object'] !== $this->holder) || (count($bt) < 2))) { throw(new Exception('Notify can only be called in holder')); } foreach ($this->callbacks as $callback) { $args = func_get_args(); call_user_func_array($callback, $args); } } }