本页文章导读:

    ▪php设计模式 Observer(观察者模式)       代码如下: <?php /** * 观察者模式 * * 定义对象间的一种一对多的依赖关系,以便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自动刷新 * 能够便利地创建查看目标对象状态.........

    ▪php设计模式 Singleton(单例模式)       代码如下: <?php /** * 单例模式 * * 保证一个类仅有一个实例,并提供一个访问它的全局访问点 * */ class Singleton { static private $_instance = null; private function __construct() { } static public function getInstance.........

    ▪php设计模式 Command(命令模式)       代码如下: <?php /** * 命令模式 * * 将一个请求封装为一个对象从而使你可用不同的请求对客户进行参数化,对请求排除或记录请求日志,以及支持可取消的操作 */ interface Command { public function ex.........

代码如下:

<?php
/**
* 观察者模式
*
* 定义对象间的一种一对多的依赖关系,以便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自动刷新
* 能够便利地创建查看目标对象状态的对象,并且提供与核心对象非耦合的指定功能
* 插件系统
*/
class Observerable
{
private $_observers = array();

public function registerObserver($observer)
{
$this->_observers[] = $observer;
}

public function removeObserver($observer)
{
$key = array_search($observer,$this->_observers);
if(!($key === false))
{
unset($this->_observers[$key]);
}
}

public function notifyObservers()
{
foreach($this->_observers as $observer)
{
if($observer instanceof Observer) $observer->update($this);
}
}
}

interface Observer
{
public function update($observer);
}

interface DisplayElement
{
public function display();
}

// -- 实例类定义
class NewsObserverable extends Observerable
{
private $_sports_news;
public function setSportsNews($data)
{
$this->_sports_news = $data;
$this->notifyObservers();
}

public function getSportsNews()
{
return $this->_sports_news;
}

private $_local_news;
public function setLocalNews($data)
{
$this->_local_news = $data;
$this->notifyObservers();
}

public function getLocalNews()
{
return $this->_local_news;
}
}

class SportsNews implements Observer,DisplayElement
{
private $_data = null;
public function update($observer)
{
if($this->_data != $observer->getSportsNews())
{
$this->_data = $observer->getSportsNews();
$this->display();
}
}

public function display()
{
echo $this->_data.date("Y-m-d H:i:s")."<br/>";
}
}

class LocalNews implements Observer,DisplayElement
{
private $_data = null;
public function update($observer)
{
if($this->_data != $observer->getLocalNews())
{
$this->_data = $observer->getLocalNews();
$this->display();
}
}

public function display()
{
echo $this->_data.date("Y-m-d H:i:s")."<br/>";
}
}

// -- 实例化 ---

$objObserver = new NewsObserverable();
$local = new LocalNews();
$sports = new SportsNews();

$objObserver->registerObserver($local);
$objObserver->registerObserver($sports);

$objObserver->setSportsNews("sports news 1 ");
$objObserver->setLocalNews("local news 1 ");
$objObserver->removeObserver($sports);
$objObserver->setLocalNews("local news 2 ");
$objObserver->setSportsNews("sports news 2 ");
$objObserver->removeObserver($local);
$objObserver->setLocalNews("local news 3 ");

代码如下:

<?php
/**
* 单例模式
*
* 保证一个类仅有一个实例,并提供一个访问它的全局访问点
*
*/
class Singleton
{
static private $_instance = null;

private function __construct()
{
}

static public function getInstance()
{
if(is_null(self::$_instance)) {
self::$_instance = new Singleton();
}
return self::$_instance;
}

public function display()
{
echo "it is a singlton class function";
}
}

// $obj = new Singleton(); // 声明不能成功
$obj = Singleton::getInstance();
var_dump($obj);
$obj->display();

$obj1 = Singleton::getInstance();
var_dump(($obj === $obj1));

代码如下:

<?php
/**
* 命令模式
*
* 将一个请求封装为一个对象从而使你可用不同的请求对客户进行参数化,对请求排除或记录请求日志,以及支持可取消的操作
*/
interface Command
{
public function execute();
}

class Invoker
{
private $_command = array();
public function setCommand($command) {
$this->_command[] = $command;
}

public function executeCommand()
{
foreach($this->_command as $command)
{
$command->execute();
}
}

public function removeCommand($command)
{
$key = array_search($command, $this->_command);
if($key !== false)
{
unset($this->_command[$key]);
}
}
}

class Receiver
{
private $_name = null;

public function __construct($name) {
$this->_name = $name;
}

public function action()
{
echo $this->_name." action<br/>";
}

public function action1()
{
echo $this->_name." action1<br/>";
}
}

class ConcreteCommand implements Command
{
private $_receiver;
public function __construct($receiver)
{
$this->_receiver = $receiver;
}

public function execute()
{
$this->_receiver->action();
}
}

class ConcreteCommand1 implements Command
{
private $_receiver;
public function __construct($receiver)
{
$this->_receiver = $receiver;
}

public function execute()
{
$this->_receiver->action1();
}
}

class ConcreteCommand2 implements Command
{
private $_receiver;
public function __construct($receiver)
{
$this->_receiver = $receiver;
}

public function execute()
{
$this->_receiver->action();
$this->_receiver->action1();
}
}


$objRecevier = new Receiver("No.1");
$objRecevier1 = new Receiver("No.2");
$objRecevier2 = new Receiver("No.3");

$objCommand = new ConcreteCommand($objRecevier);
$objCommand1 = new ConcreteCommand1($objRecevier);
$objCommand2 = new ConcreteCommand($objRecevier1);
$objCommand3 = new ConcreteCommand1($objRecevier1);
$objCommand4 = new ConcreteCommand2($objRecevier2); // 使用 Recevier的两个方法

$objInvoker = new Invoker();
$objInvoker->setCommand($objCommand);
$objInvoker->setCommand($objCommand1);
$objInvoker->executeCommand();
$objInvoker->removeCommand($objCommand1);
$objInvoker->executeCommand();

$objInvoker->setCommand($objCommand2);
$objInvoker->setCommand($objCommand3);
$objInvoker->setCommand($objCommand4);
$objInvoker->executeCommand();