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Copy pathObserverPattern.php
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105 lines (88 loc) · 2.24 KB
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<?php
/**
* This is observer pattern of design pattern
* 观察者模式是一种行为型模式,它定义对象间的一种一对多的依赖关系,
* 当一个对象的状态发生改变时,所有依赖于它的对象得到通知并自动更新
*
* @author hkf <[email protected]>
* @version 0.1.0
*/
/**
* Interface Subject
* 抽象主题角色
*/
interface Subject
{
public function attach(Observer $observer); // 增加一个新的观察者对象
public function detach(Observer $observer); // 删除一个已注册过的观察者对象
public function notifyObservers(); // 通知所有注册过的观察者对象
}
/**
* Class ConcreteSubject
* 具体主题角色
*/
class ConcreteSubject implements Subject
{
private $_observers;
public function __construct()
{
$this->_observers = array();
}
public function attach(Observer $observer)
{
return array_push($this->_observers, $observer);
}
public function detach(Observer $observer)
{
$index = array_search($observer, $this->_observers);
if ($index === FALSE || !array_key_exists($index, $this->_observers)) {
return FALSE;
}
unset($this->_observers[$index]);
return TRUE;
}
public function notifyObservers()
{
if (!is_array($this->_observers)) {
return FALSE;
}
foreach ($this->_observers as $observer) {
$observer->update();
}
return TRUE;
}
}
/**
* Interface Observer
* 抽象观察者角色
*/
interface Observer
{
public function update(); // 更新方法
}
/**
* Class ConcreteObserver
* 具体观察者角色
*/
class ConcreteObserver implements Observer
{
private $_name;
public function __construct($name)
{
$this->_name = $name;
}
public function update()
{
}
}
$subject = new ConcreteSubject();
/* 添加第一个观察者 */
$observer1 = new ConcreteObserver('Mac');
$subject->attach($observer1);
$subject->notifyObservers(); // 主题变化，通知观察者
/* 添加第二个观察者 */
$observer2 = new ConcreteObserver('Win');
$subject->attach($observer2);
$subject->notifyObservers();
$subject->detach($observer1);
$subject->notifyObservers();