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Observer.php
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113 lines (104 loc) · 2.26 KB
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<?php
/**
* * 抽象主题角色
* */
interface Subject
{
/**
** 增加一个新的观察者对象
** @param Observer $observer
**/
public function attach(Observer $observer);
/**
** 删除一个已注册过的观察者对象
** @param Observer $observer
**/
public function detach(Observer $observer);
/**
** 通知所有注册过的观察者对象
**/
public function notifyObservers();
}
/**
* * 具体主题角色
* */
class ConcreteSubject implements Subject
{
private $_observers;
public function __construct()
{
$this->_observers = array();
}
/**
** 增加一个新的观察者对象
** @param Observer $observer
**/
public function attach(Observer $observer)
{
return array_push($this->_observers, $observer);
}
/**
** 删除一个已注册过的观察者对象
** @param Observer $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[$index]);
return true;
}
/**
** 通知所有注册过的观察者对象
**/
public function notifyObservers()
{
if (!is_array($this->_observers)) {
return false;
}
foreach ($this->_observers as $observer) {
$observer->update();
}
return true;
}
}
/**
* * 抽象观察者角色
* */
interface Observer
{
/**
** 更新方法
* */
public function update();
}
class ConcreteObserver implements Observer
{
/**
** 观察者的名称
** @var <type>
**/
private $_name;
public function __construct($name)
{
$this->_name = $name;
}
/**
** 更新方法
**/
public function update()
{
echo 'Observer', $this->_name, ' has notified.';
}
}
//实例化类
$subject = new ConcreteSubject();
/* 添加第一个观察者 */
$observer1 = new ConcreteObserver('Martin');
$subject->attach($observer1);
/* 添加第二个观察者 */
$observer2 = new ConcreteObserver('phppan');
$subject->attach($observer2);
$subject->notifyObservers();