设计模式之观察者模式&&状态模式

<?php

interface Subject {
	function attach($obj);
	function detach($name);
	function notify();
}

class Teacher implements Subject {
	private $attachArr = array();

	function __construct() {
	}

	function attach($obj) {
    	array_push($this->attachArr, $obj);
	}

	function detach($name) {
		unset($name);
	}

	function notify() {
		foreach($this->attachArr as $obj) {
			$obj->work();
		}
	}

	function setStatus($status) {
		$this->status = $status;
	}


}

interface Observe {
    function work();
}

class Student implements Observe {

	function __construct($name, $work, $subjectObj) {
		$this->name = $name;
		$this->subjectObj = $subjectObj;
		$this->work = $work;
	}

	function work() {
		echo $this->subjectObj->status . "\n" .$this->name . $this->work . " \n";
	}
}
$teacher = new Teacher();
$student1 = new Student('joey', 'paly table tenice', $teacher);
$student2 = new Student('jam', 'sleeping', $teacher);

$teacher->attach($student1);
$teacher->attach($student2);
$teacher->setStatus("quitting time \n");

$teacher->notify();

 

以上代码为观察者模式

观察者模式为当一个对象的状态改变的时候，其他的关联对象也做出相应。

观察者模式缺点：每个观察者对象必须继承这个抽像出来的接口类(比如这里的work)，这样就造成了一些不方便，

可以通过委托实现。

 

<?php
//状态模式

abstract class State {
	abstract  function writeProgram(Work $work);
}

class ForenoonState extends State {
	function writeProgram(Work $work) {
	  if ($work->hour < 12) {
	     echo '当前时间是上午' . $work->hour . '工作精神百倍噢';
	  } else {
	     $work->setState(new NoonState());
		 $work->writeProgram();
	  }

	}
}

class NoonState extends State {
    function writeProgram(Work $work) {
	    if ($work->hour < 13 && $work->hour >= 12) {
		   echo '当前时间是' . $work->hour . '午饭时间有点饿';
		} else {
		   $work->setState( new AfternoonState());
		   $work->writeProgram();
		}
	}
}

class AfternoonState extends State {
    function writeProgram(Work $work) {
		if ($work->hour > 13 && $work->hour < 17) {
		   echo '当前时间是' . $work->hour . '状态不错继续努力';
		} else {
		   $work->setState(new EveningState());
		   $work->writeProgram();
		}
	}
}

class EveningState extends State {
    function writeProgram(Work $work) {
	    if ($work->finish) {
			$work->setState(new RestState());
			$work->writeProgram();
		} else {
		    if ($work->hour < 21) {
               echo '当前时间是' . $work->hour . '加班悲剧了';
			}
		}
	}
}

class RestState extends State {
    function writeProgram(Work $work) {
	    echo '当前时间是' . $work->hour . '下班回家了';
	}
}

class Work {
    private $state;
	public  $hour;
	public  $finish = false; 
	function __construct() {
	    $this->state = new ForenoonState();
	}

	function setState($state) {
		$this->state = $state;
	}

	function taskFinished() {
		$this->finish = true;
	}
	function writeProgram() {
		$this->state->writeProgram($this);
	}
}

$task = new Work();
$task->hour = 8;
$task->writeProgram();
$task->hour = 12;
$task->writeProgram();

$task->hour = 15;
$task->writeProgram();
$task->hour = 20;
$task->taskFinished();
$task->writeProgram();

状态模式适应于当判断逻辑太长的时候，当有新的状态添加不用修改原来的状态的代码。