代码片段一:
<?php
/**
* 观察者模式:定于对象间的一种一对多的依赖关系,当一个对象发生改变时,所有依赖它的对象都收到通知并自动更新。
*/ //例子:少林方丈的通讯录,当扫地僧的号码发生变化时,只需告诉方丈,方丈可通知自己通讯录里面的所有人
interface Contacts{
public function addTel($tel);
public function delTel($tel);
public function notify();
public function action($action);
} class StuContact implements Contacts{
public $contact;
public $action;
public function addTel($tel){
$this->contact[] = $tel;
} public function delTel($tel){
$key = array_search($tel, $this->contact);
if($key !== FALSE){
unset($this->contact[$key]);
}else{
echo '通讯录中无此人';
}
} public function notify(){
echo $this->action;
echo "<br/>";
foreach ($this->contact as $tel){
$tel->update();
echo "<br/>";
}
} public function action($action){
$this->action = $action;
}
} interface Tel{
public function update();
} class StuTel implements Tel{
public $name;
public function __construct($name){
$this->name = $name;
} public function update(){
echo $this->name.'收到消息,已经更新';
}
} class Client{
public static function main(){
$tel1 = new StuTel('虚竹');
$tel2 = new StuTel('乔峰');
$tel3 = new StuTel('段誉'); $contacts = new StuContact();
$contacts->addTel($tel1);
$contacts->addTel($tel2);
$contacts->addTel($tel3); $contacts->action('扫地僧的号码更新了,是11111');
$contacts->notify();
}
} Client::main();
?>
代码片段2
<?php
/*
* 观察者模式:定义对象间的一种一对多的依赖关系,当一个对象的状态发生改变时,所有依赖于它的对象都得到通知并被自动更新。
* 类型:行为类模式
*
*
*/ //抽象主题角色
interface Subject
{
public function Attach($Observer); //添加观察者
public function Detach($Observer); //踢出观察者
public function Notify(); //满足条件时通知观察者
public function SubjectState($Subject); //观察条件
} //具体主题角色
class Boss Implements Subject
{
public $_action;
private $_Observer;
public function Attach($Observer)
{
$this->_Observer[] = $Observer;
}
public function Detach($Observer)
{
$ObserverKey = array_search($Observer, $this->_Observer);
if($ObserverKey !== false)
{
unset($this->_Observer[$ObserverKey]);
}
}
public function Notify()
{
foreach($this->_Observer as $value )
{
$value->Update();
}
}
public function SubjectState($Subject)
{
$this->_action = $Subject;
}
} //抽象观察者角色
abstract class Observer
{
protected $_UserName;
protected $_Sub;
public function __construct($Name,$Sub)
{
$this->_UserName = $Name;
$this->_Sub = $Sub;
}
public abstract function Update(); //接收通过方法
}
//具体观察者角色
class StockObserver extends Observer
{
public function __construct($name,$sub)
{
parent::__construct($name,$sub);
}
public function Update()
{
echo $this->_Sub->_action.$this->_UserName." 你赶快跑...";
}
}
$huhansan = new Boss(); //被观察者
$gongshil = new StockObserver("三毛",$huhansan); //初始化观察者
$huhansan->Attach($gongshil); //添加一个观察者
$huhansan->Attach($gongshil); //添加一个相同的观察者
//$huhansan->Detach($gongshil); //踢出基中一个观察者
$huhansan->SubjectState("警察来了"); //达到满足的条件
$huhansan->Notify(); //通过所有有效的观察者
?>
UML类图如下