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Php design patterns: behavioral patterns (2)
- 巴扎黑Original
- 2016-11-12 11:50:401048browse
7a6edc53a1766025dd3070dcd5a69369
4. Observer mode (Observer):
)． response. Just like a newspaper, everyone who reads the news today will see the same content. Same thing if another newspaper is published.通The benefits: broadcast -type communication, large scope, one hundred response, which is convenient for operating a group, "public ownership".
Disadvantages: Individuals in the group cannot be operated independently, and allocation on demand cannot be implemented.
Application scenario: Operate multiple objects and perform the same operation.
Code implementation:
[php] view plaincopy
<?php
/**
* 优才网公开课示例代码
*
* 观察者模式 Observer
*
* @author 优才网全栈工程师教研组
* @see http://www.ucai.cn
*/
function output($string) {
echo $string . "\n";
}
//订单数据对象简单模拟，这个是实际需要被观察的对象(Subject)，但是我们将其独立，然后
//通过构造方法传入到我们模式中的Subject中，这样使具体业务更加独立
class Order{
//订单号
private $id = '';
//用户ID
private $userId = '';
//用户名
private $userName = '';
//价格
private $price = '';
//下单时间
private $orderTime = '';
//订单数据填充简单模拟，实际应用中可能会读取用户表单输入并处理
public function __set($name, $value){
if (isset($this->$name)){
$this->$name = $value;
}
}
//获取订单属性
public function __get($name){
if (isset($this->$name)){
return $this->$name;
}
return "";
}
}
//假设的DB类，便于测试，实际会存入真实数据库
class FakeDB{
public function save($data){
return true;
}
}
class Client {
public static function test() {
//初始化一个订单数据
$order = new Order();
$order->id = 1001;
$order->userId = 9527;
$order->userName = "God";
$order->price = 20.0;
$order->orderTime = time();
//向数据库保存订单
$db = new FakeDB();
$result = $db->save($order);
if ($result){
//实际应用可能会写到日志文件中，这里直接输出
output( "[OrderId:{$order->id}] [UseId:{$order->userId}] [Price:{$order->price}]" );
//实际应用会调用邮件发送服务如sendmail，这里直接输出
output( "Dear {$order->userName}: Your order {$order->id} was confirmed!" );
//实际应用会调用邮件发送服务如sendmail，这里直接输出
output( "Dear Manager: User {$order->userName}(ID:{$order->userId}) submitted a new order {$order->id}, please handle it ASAP!" );
}
}
}
Client::test();
<?php
/**
* 优才网公开课示例代码
*
* 观察者模式 Observer
*
* @author 优才网全栈工程师教研组
* @see http://www.ucai.cn
*/
function output($string) {
echo $string . "\n";
}
//订单数据对象简单模拟，这个是实际需要被观察的对象(Subject)，但是我们将其独立，然后
//通过构造方法传入到我们模式中的Subject中，这样使具体业务更加独立
class Order{
//订单号
private $id = '';
//用户ID
private $userId = '';
//用户名
private $userName = '';
//价格
private $price = '';
//下单时间
private $orderTime = '';
//订单数据填充简单模拟，实际应用中可能会读取用户表单输入并处理
public function __set($name, $value){
if (isset($this->$name)){
$this->$name = $value;
}
}
//获取订单属性
public function __get($name){
if (isset($this->$name)){
return $this->$name;
}
return "";
}
}
//被观察者, 负责维护观察者并在变化发生是通知观察者
class OrderSubject implements SplSubject {
private $observers;
private $order;
public function __construct(Order $order) {
$this->observers = new SplObjectStorage();
$this->order = $order;
}
//增加一个观察者
public function attach(SplObserver $observer) {
$this->observers->attach($observer);
}
//移除一个观察者
public function detach(SplObserver $observer) {
$this->observers->detach($observer);
}
//通知所有观察者
public function notify() {
foreach ($this->observers as $observer) {
$observer->update($this);
}
}
//返回主体对象的具体实现，供观察者调用
public function getOrder() {
return $this->order;
}
}
//记录业务数据日志 (ActionLogObserver)，实际可能还要抽象一层以处理不同的Action(业务操作)，这里省略
class ActionLogObserver implements SplObserver{
public function update(SplSubject $subject) {
$order = $subject->getOrder();
//实际应用可能会写到日志文件中，这里直接输出
output( "[OrderId:{$order->id}] [UseId:{$order->userId}] [Price:{$order->price}]" );
}
}
//给用户发送订单确认邮件 (UserMailObserver)
class UserMailObserver implements SplObserver{
public function update(SplSubject $subject) {
$order = $subject->getOrder();
//实际应用会调用邮件发送服务如sendmail，这里直接输出
output( "Dear {$order->userName}: Your order {$order->id} was confirmed!" );
}
}
//给管理人员发订单处理通知邮件 (AdminMailObserver)
class AdminMailObserver implements SplObserver{
public function update(SplSubject $subject) {
$order = $subject->getOrder();
//实际应用会调用邮件发送服务如sendmail，这里直接输出
output( "Dear Manager: User {$order->userName}(ID:{$order->userId}) submitted a new order {$order->id}, please handle it ASAP!" );
}
}
//假设的DB类，便于测试，实际会存入真实数据库
class FakeDB{
public function save($data){
return true;
}
}
class Client {
public static function test() {
//初始化一个订单数据
$order = new Order();
$order->id = 1001;
$order->userId = 9527;
$order->userName = "God";
$order->price = 20.0;
$order->orderTime = time();
//绑定观察者
$subject = new OrderSubject($order);
$actionLogObserver = new ActionLogObserver();
$userMailObserver = new UserMailObserver();
$adminMailObserver = new AdminMailObserver();
$subject->attach($actionLogObserver);
$subject->attach($userMailObserver);
$subject->attach($adminMailObserver);
//向数据库保存订单
$db = new FakeDB();
$result = $db->save($order);
if ($result){
//通知观察者
$subject->notify();
}
}
}
Client::test();
5. Mediator pattern (Mediator):
Use mediation objects to encapsulate a series of objects interaction, the intermediary enables each Objects do not need to explicitly reference each other. Similar to the post office, the mailer and recipient do not need to travel far themselves, they can just go through the post office.
Benefits: Simplifies the relationship between objects and reduces the generation of subclasses.
Disadvantages: Intermediary objects may become very complex and the system is difficult to maintain.
Application scenario: Establish interaction without display.
Code implementation:
[php] view plaincopy
<?php
/**
* 优才网公开课示例代码
*
* 中介者模式 Mediator
*
* @author 优才网全栈工程师教研组
* @see http://www.ucai.cn
*/
function output($string) {
echo $string . "\n";
}
abstract class Mediator { // 中介者角色
abstract public function send($message,$colleague);
}
abstract class Colleague { // 抽象对象
private $_mediator = null;
public function __construct($mediator) {
$this->_mediator = $mediator;
}
public function send($message) {
$this->_mediator->send($message,$this);
}
abstract public function notify($message);
}
class ConcreteMediator extends Mediator { // 具体中介者角色
private $_colleague1 = null;
private $_colleague2 = null;
public function send($message,$colleague) {
if($colleague == $this->_colleague1) {
$this->_colleague1->notify($message);
} else {
$this->_colleague2->notify($message);
}
}
public function set($colleague1,$colleague2) {
$this->_colleague1 = $colleague1;
$this->_colleague2 = $colleague2;
}
}
class Colleague1 extends Colleague { // 具体对象角色
public function notify($message) {
output(sprintf('Colleague-1: %s', $message));
}
}
class Colleague2 extends Colleague { // 具体对象角色
public function notify($message) {
output(sprintf('Colleague-2: %s', $message));
}
}
class Client {
public static function test(){
// client
$objMediator = new ConcreteMediator();
$objC1 = new Colleague1($objMediator);
$objC2 = new Colleague2($objMediator);
$objMediator->set($objC1,$objC2);
$objC1->send("to c2 from c1");
$objC2->send("to c1 from c2");
}
}
Client::test();
6. State mode (State):
Objects show different behaviors in different states. Just like a girlfriend, she holds your hand when she is happy and walks the dog when she is unhappy. Show different behaviors in the two states.
Advantages: It is practical to avoid if statements, convenient for adding new states, and encapsulates state transition rules.
Disadvantages: Increase the number of system classes and objects.
Application scenarios: Used for conversion of different functions of objects.
Code implementation:
[php] view plaincopy
<?php
/**
* 优才网公开课示例代码
*
* 状态模式 State
*
* @author 优才网全栈工程师教研组
* @see http://www.ucai.cn
*/
function output($string) {
echo $string . "\n";
}
abstract class ILift {
//电梯的四个状态
const OPENING_STATE = 1; //门敞状态
const CLOSING_STATE = 2; //门闭状态
const RUNNING_STATE = 3; //运行状态
const STOPPING_STATE = 4; //停止状态；
//设置电梯的状态
public abstract function setState($state);
//首先电梯门开启动作
public abstract function open();
//电梯门有开启，那当然也就有关闭了
public abstract function close();
//电梯要能上能下，跑起来
public abstract function run();
//电梯还要能停下来
public abstract function stop();
}
/**
* 电梯的实现类
*/
class Lift extends ILift {
private $state;
public function setState($state) {
$this->state = $state;
}
//电梯门关闭
public function close() {
//电梯在什么状态下才能关闭
switch ($this->state) {
case ILift::OPENING_STATE: //如果是则可以关门，同时修改电梯状态
$this->setState(ILift::CLOSING_STATE);
break;
case ILift::CLOSING_STATE: //如果电梯就是关门状态，则什么都不做
//do nothing;
return ;
break;
case ILift::RUNNING_STATE: //如果是正在运行，门本来就是关闭的，也说明都不做
//do nothing;
return ;
break;
case ILift::STOPPING_STATE: //如果是停止状态，本也是关闭的，什么也不做
//do nothing;
return ;
break;
}
output('Lift colse');
}
//电梯门开启
public function open() {
//电梯在什么状态才能开启
switch($this->state){
case ILift::OPENING_STATE: //如果已经在门敞状态，则什么都不做
//do nothing;
return ;
break;
case ILift::CLOSING_STATE: //如是电梯时关闭状态，则可以开启
$this->setState(ILift::OPENING_STATE);
break;
case ILift::RUNNING_STATE: //正在运行状态，则不能开门，什么都不做
//do nothing;
return ;
break;
case ILift::STOPPING_STATE: //停止状态，淡然要开门了
$this->setState(ILift::OPENING_STATE);
break;
}
output('Lift open');
}
///电梯开始跑起来
public function run() {
switch($this->state){
case ILift::OPENING_STATE: //如果已经在门敞状态，则不你能运行，什么都不做
//do nothing;
return ;
break;
case ILift::CLOSING_STATE: //如是电梯时关闭状态，则可以运行
$this->setState(ILift::RUNNING_STATE);
break;
case ILift::RUNNING_STATE: //正在运行状态，则什么都不做
//do nothing;
return ;
break;
case ILift::STOPPING_STATE: //停止状态，可以运行
$this->setState(ILift::RUNNING_STATE);
}
output('Lift run');
}
//电梯停止
public function stop() {
switch($this->state){
case ILift::OPENING_STATE: //如果已经在门敞状态，那肯定要先停下来的，什么都不做
//do nothing;
return ;
break;
case ILift::CLOSING_STATE: //如是电梯时关闭状态，则当然可以停止了
$this->setState(ILift::CLOSING_STATE);
break;
case ILift::RUNNING_STATE: //正在运行状态，有运行当然那也就有停止了
$this->setState(ILift::CLOSING_STATE);
break;
case ILift::STOPPING_STATE: //停止状态，什么都不做
//do nothing;
return ;
break;
}
output('Lift stop');
}
}
class Client {
public static function test() {
$lift = new Lift();
//电梯的初始条件应该是停止状态
$lift->setState(ILift::STOPPING_STATE);
//首先是电梯门开启，人进去
$lift->open();
//然后电梯门关闭
$lift->close();
//再然后，电梯跑起来，向上或者向下
$lift->run();
//最后到达目的地，电梯挺下来
$lift->stop();
}
}
Client::test();
<?php
/**
* 优才网公开课示例代码
*
* 状态模式 State
*
* @author 优才网全栈工程师教研组
* @see http://www.ucai.cn
*/
function output($string) {
echo $string . "\n";
}
/**
*
* 定义一个电梯的接口
*/
abstract class LiftState{
//定义一个环境角色，也就是封装状态的变换引起的功能变化
protected $_context;
public function setContext(Context $context){
$this->_context = $context;
}
//首先电梯门开启动作
public abstract function open();
//电梯门有开启，那当然也就有关闭了
public abstract function close();
//电梯要能上能下，跑起来
public abstract function run();
//电梯还要能停下来，停不下来那就扯淡了
public abstract function stop();
}
/**
* 环境类:定义客户感兴趣的接口。维护一个ConcreteState子类的实例，这个实例定义当前状态。
*/
class Context {
//定义出所有的电梯状态
static $openningState = null;
static $closeingState = null;
static $runningState = null;
static $stoppingState = null;
public function __construct() {
self::$openningState = new OpenningState();
self::$closeingState = new ClosingState();
self::$runningState = new RunningState();
self::$stoppingState = new StoppingState();
}
//定一个当前电梯状态
private $_liftState;
public function getLiftState() {
return $this->_liftState;
}
public function setLiftState($liftState) {
$this->_liftState = $liftState;
//把当前的环境通知到各个实现类中
$this->_liftState->setContext($this);
}
public function open(){
$this->_liftState->open();
}
public function close(){
$this->_liftState->close();
}
public function run(){
$this->_liftState->run();
}
public function stop(){
$this->_liftState->stop();
}
}
/**
* 在电梯门开启的状态下能做什么事情
*/
class OpenningState extends LiftState {
/**
* 开启当然可以关闭了，我就想测试一下电梯门开关功能
*
*/
public function close() {
//状态修改
$this->_context->setLiftState(Context::$closeingState);
//动作委托为CloseState来执行
$this->_context->getLiftState()->close();
}
//打开电梯门
public function open() {
output('lift open...');
}
//门开着电梯就想跑，这电梯，吓死你！
public function run() {
//do nothing;
}
//开门还不停止？
public function stop() {
//do nothing;
}
}
/**
* 电梯门关闭以后，电梯可以做哪些事情
*/
class ClosingState extends LiftState {
//电梯门关闭，这是关闭状态要实现的动作
public function close() {
output('lift close...');
}
//电梯门关了再打开，逗你玩呢，那这个允许呀
public function open() {
$this->_context->setLiftState(Context::$openningState); //置为门敞状态
$this->_context->getLiftState()->open();
}
//电梯门关了就跑，这是再正常不过了
public function run() {
$this->_context->setLiftState(Context::$runningState); //设置为运行状态；
$this->_context->getLiftState()->run();
}
//电梯门关着，我就不按楼层
public function stop() {
$this->_context->setLiftState(Context::$stoppingState); //设置为停止状态；
$this->_context->getLiftState()->stop();
}
}
/**
* 电梯在运行状态下能做哪些动作
*/
class RunningState extends LiftState {
//电梯门关闭？这是肯定了
public function close() {
//do nothing
}
//运行的时候开电梯门？你疯了！电梯不会给你开的
public function open() {
//do nothing
}
//这是在运行状态下要实现的方法
public function run() {
output('lift run...');
}
//这个事绝对是合理的，光运行不停止还有谁敢做这个电梯？！估计只有上帝了
public function stop() {
$this->_context->setLiftState(Context::$stoppingState); //环境设置为停止状态；
$this->_context->getLiftState()->stop();
}
}
/**
* 在停止状态下能做什么事情
*/
class StoppingState extends LiftState {
//停止状态关门？电梯门本来就是关着的！
public function close() {
//do nothing;
}
//停止状态，开门，那是要的！
public function open() {
$this->_context->setLiftState(Context::$openningState);
$this->_context->getLiftState()->open();
}
//停止状态再跑起来，正常的很
public function run() {
$this->_context->setLiftState(Context::$runningState);
$this->_context->getLiftState()->run();
}
//停止状态是怎么发生的呢？当然是停止方法执行了
public function stop() {
output('lift stop...');
}
}
/**
* 模拟电梯的动作
*/
class Client {
public static function test() {
$context = new Context();
$context->setLiftState(new ClosingState());
$context->open();
$context->close();
$context->run();
$context->stop();
}
}
Client::test();
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