PHP设计模式之：策略模式

浏览数：37 / 时间：2015年06月09日

<?php
abstract class Strategy
{
   public abstract function AlgorithmInterface();
}

class ConcreteStrategyA extends Strategy
{
   public function AlgorithmInterface()
   {
       // 实现细节
   }
}

class ConcreteStrategyB extends Strategy
{
   public function AlgorithmInterface()
   {
       // 实现细节
   }
}

class ConcreteStrategyC extends Strategy
{
   public function AlgorithmInterface()
   {
       // 实现细节
   }
}

/* *************************************** */
// 配置
class Context
{
   public $strategy;

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

   public function ContextInterface()
   {
       $this->strategy->AlgorithmInterface();
   }
}

// 实现过程
$context = new Context(new ConcreteStrategyA());
$context.ContextInterface();

$context = new Context(new ConcreteStrategyB());
$context.ContextInterface();

$context = new Context(new ConcreteStrategyC());
$context.ContextInterface();

/* ********************************* */
// 策略模式具体实现

abstract class CashSuper
{
   public abstract function acceptCash($money);
}

// 正常收费
class CashNormal extends CashSuper
{
   public function acceptCash($money)
   {
       return $money;
   }
}

// 打折收费
class CashRebate extends CashSuper
{
   private $moneyReturn;

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

   public function acceptCash($money)
   {
       return $money * $this->moneyReturn;
   }
}

// 返利收费
class CashReturn extends CashSuper
{
   private $moneyCondtion;
   private $moneyReturn;

   function __construct($moneyCondition, $moneyReturn)
   {
       $this->moneyCondtion = $moneyCondition;
       $this->moneyReturn = $moneyReturn;
   }

   public function acceptCash($money)
   {
       $result = $money;
       if($money >= $this->moneyCondtion)
           $result = $money - Math.Float($money/$this->moneyCondition) * $this->moneyReturn;
       return $result;
   }
}

// 实现

class CashContext
{
   // 为一个构造实现一子类
   private cs;
   public function __construct($cashSuper)
   {
       $this->cs = $cashSuper;
   }

   public function GetResult($money)
   {
       return cs.acceptCash($money);
   }
}
/**
   @param $flag 检测收费方式
   @param $old 正常价格
   @param $back 返回利率
   @param $condtion 正常价格
   @param $conditionback 应返回的利率
   @param $money 实现的金额
*/
$flag;
$old, $back;
$condtion, $conditionback;
$money;
switch($flag)
{
   case "normal":
       $res = new CashContext(new CashNormal());
       break;
case "打折":
       $res = new CashContext(new CashRebate($old, $back));
       break;
   case "返利":
       $res = new CashContext(new CashReturn($conditon, $conditionback));
       break;
}
$res.acceptCash($money);

/** ********************************** */
// 策略模式与工厂模式结合，只需修改 CashContext即可

/**
   @param $flag 检测收费方式
   @param $old 正常价格
   @param $back 返回利率
   @param $condtion 正常价格
   @param $conditionback 应返回的利率
   @param $money 实现的金额
*/
// 用到时把参数修改为实际数字即可
class CashContext
{
   // 为一个构造实现一子类
   private cs;
   private $flag;
   public function __construct($flag)
   {
       $this->flag = $flag;
   }

   public function GetResult($money)
   {
       switch($this->flag)
       {
           case "normal":
               $res = new CashContext(new CashNormal());
               break;
           case "打折":
               $res = new CashContext(new CashRebate($old, $back));
               break;
           case "返利":
               $res = new CashContext(new CashReturn($conditon, $conditionback));
               break;
       }
       return $res.acceptCash($money);
   }
}

$flag;
$res = new CashContext($flag);
$res.acceptCash($money);