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。