PHP设计模式入门之状态模式原理与实现方法分析

<?php
/**
 * 饮料机
 * @author ben
 *
 */
class JuiceMachine{
 /**
 * 糖果机一共存在四种状态：没钱，有钱，成功售出以及销售一空
 * 
 * 没钱的状态
 * @var INT
 */
 const NOMONEY = 0;
 
 /**
 * 有钱的状态
 * @var INT
 */
 const HASMONEY = 1;
 
 /**
 * 成功售出的状态
 * @var INT
 */
 const SOLD = 2;
 
 /**
 * 销售一空的状态
 * @var INT
 */
 const SOLDOUT = 3;
 
 /**
 * 记录糖果机当前的状态，初始化状态为售空
 * @var INT
 */
 private $_state = JuiceMachine::SOLDOUT;
 
 /**
 * 该变量用于记录饮料机中饮料的数量
 */
 private $_count; 
 
 /**
 * 构造方法，最主要是用来初始化count和state属性的
 */
 public function __construct($count){
   $this->_count = $count;
   //当饮料机中的饮料数量大于零时，将饮料机的状态重置为没有钱的状态。
   if($this->_count > 0){
     $this->_state = JuiceMachine::NOMONEY;
   }
 }
 
 /**
 * 投入硬币
 */
 public function insertCoin(){
   if($this->_state == JuiceMachine::HASMONEY ){
     echo "you can't insert another coin!<br />";
   }elseif($this->_state == JuiceMachine::NOMONEY){
     echo "you just insert a coin<br />";
     $this->_state = JuiceMachine::HASMONEY;
   }elseif($this->_state == JuiceMachine::SOLD){
     echo "wait a minute, we are giving you a bottle of juice<br />";
   }elseif($this->_state == JuiceMachine::SOLDOUT){
     echo "you can't insert coin, the machine is already soldout<br />";
   }
 }
 
 /**
 * 退回硬币
 */
 public function retreatCoin(){
   if($this->_state == JuiceMachine::HASMONEY ){
     echo "coin return!<br />";
     $this->_state = JuiceMachine::NOMONEY;
   }elseif($this->_state == JuiceMachine::NOMONEY){
     echo "you have'nt inserted a coin yet<br />";
   }elseif($this->_state == JuiceMachine::SOLD){
     echo "sorry, you already clicked the botton<br />";
   }elseif($this->_state == JuiceMachine::SOLDOUT){
     echo "you have'nt inserted a coin yet<br />";
   }
 }
 
 /**
 * 点击饮料对应的按钮
 */
 public function clickButton(){
   if($this->_state == JuiceMachine::HASMONEY ){
     echo "you clicked, we are giving you a bottle of juice...<br />";
     $this->_state = JuiceMachine::SOLD;  //改变饮料机的状态为售出模式
     $this->dispend();
   }elseif($this->_state == JuiceMachine::NOMONEY){
     echo "you clicked,but you hav'nt inserted a coin yet<br />";
   }elseif($this->_state == JuiceMachine::SOLD){
     echo "click twice does'nt get you two bottle of juice<br />";
   }elseif($this->_state == JuiceMachine::SOLDOUT){
     echo "you clicked, but the machine is already soldout<br />";
   }
 }
 
 /**
 * 发放饮料
 */
 public function dispend(){
   if($this->_state == JuiceMachine::HASMONEY ){
     echo "please click the button first<br />";
   }elseif($this->_state == JuiceMachine::NOMONEY){
     echo "you need to pay first<br />";
   }elseif($this->_state == JuiceMachine::SOLD){
     echo "now you get you juice<br />";
     //饮料机中的饮料数量减一
     $this->_count--;
     if($this->_count <= 0){
       echo "opps, runing out of juice<br />";
       //如果这时饮料机中没有饮料了，将饮料机的状态重置为销售一空
       $this->_state = JuiceMachine::SOLDOUT;
     }else{
       //将饮料机的状态重置为没有钱
       $this->_state = JuiceMachine::NOMONEY;
     }
   }elseif($this->_state == JuiceMachine::SOLDOUT){
     //其实这种情况不应该出现
     echo "opps, it appears that we don't have any juice left<br />";
   }
 }
}