觀察者模式
在此種模式中昭抒，一個(gè)目標(biāo)物件管理所有相依于它的觀察者物件挎峦，并且在它本身的狀態(tài)改變時(shí)主動(dòng)發(fā)出通知阻逮。這通常透過(guò)呼叫各觀察者所提供的方法來(lái)實(shí)現(xiàn)钻哩。此種模式通常被用來(lái)實(shí)現(xiàn)事件處理系統(tǒng)。
Demo：
//抽象通知者
abstract class Subject
{
private $observers = array();
public function Attach(Observer $observer)
{
array_push($this->observers,$observer);
}
public function Detach(Observer $observer)
{
foreach($this->observers as $k=>$v)
{
if($v==$observer)
{
unset($this->observers[$k]);
}
}
}
function Notify()
{
foreach($this->observers as $v)
{
$v->Update();
}
}
}
//具體通知者（Boss和Secretary）
class ConcreteSubject extends Subject
{
public $subject_state;
}
//抽象觀察者
abstract class Observer
{
public abstract function Update();
}
//具體觀察者
class ConcreteObserver extends Observer
{
private $name;
private $observerState;
public $subject;
public function __construct(ConcreteSubject $_sub,$_name)
{
$this->subject = $_sub;
$this->name = $_name;
}
public function Update()
{
$this->observerState = $this->subject->subject_state;
echo "觀察者".$this->name."的新?tīng)顟B(tài)是:".$this->observerState."<br/>";
}
}
//-------------------------觀察者模式-----------------------
require_once "./Observe/Observe.php";
//前臺(tái)
$_s = new ConcreteSubject();
//寶銀
$baoyin = new ConcreteObserver($_s, "張三");
$jiangchao = new ConcreteObserver($_s,"李四");
//前臺(tái)記下寶銀姜超
$_s->Attach($baoyin);
$_s->Attach($jiangchao);
//前臺(tái)發(fā)現(xiàn)老板回來(lái)
$_s->subject_state = "孫總回來(lái)了";
//前臺(tái)發(fā)送通知
$_s->Notify();
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