php 商场收银收费系统,使用的策略模式

<?php
//策略模式就是你有很多的方法,选择一种适合自己的,
//    单例模式就是只有一个实例对象,不需要每个文件都要加载,比如连接数据库,
//    工厂模式就是

//策略模式   优惠系统、工资计算系统
//工厂模式   主要应用在多数据库选择，类库文件加载等

//商场收银系统有正常收费,打折收费,返利收费模式
interface cashStrategy{
    public function acceptCash($money);
}
//正常收费
class NormalStrategy implements cashStrategy{
    public function acceptCash($money){
        return $money;
    }
}
//打折收费
class RebateStrategy implements cashStrategy{
    //打折比例
    private $moneyRebate = 1;
    public function __construct($rebate){
        $this->moneyRebate = $rebate;
    }
    public function acceptCash($money){
        return $this->moneyRebate*$money;
    }
}
//返利收费
class ReturnStrategy implements cashStrategy{
    //返利条件
    private $moneyCondition = null;
    //返利多少
    private $moneyReturn = null;
    public function __construct($moneyCondition ,$moneyReturn){
        $this->moneyCondition = $moneyCondition;
        $this->moneyReturn = $moneyReturn;
    }
    public function acceptCash($money){
        if(!isset($this->moneyCondition) || !isset($this->moneyReturn) || $this->moneyCondition == 0)
            return $money;
        return $money - floor($money/$this->moneyCondition)*$this->moneyReturn;
    }
}

// 加载所有的策略

// 创建一个环境类，根据不同的需求调用不同策略
class Factory{
    private $_strategy = null;
    public function __construct($type = null){
        if(!isset($type))
            return;
        $this->setCashStrategy($type);

    }
    public function setCashStrategy($type){
        $cs = null;
        switch($type){
            case 'normal':
                $cs = new NormalStrategy();
                break;
            case 'rebate8':
                $cs = new RebateStrategy(0.8);
                break;
            case 'return300to100':
                $cs = new ReturnStrategy(300,100);
                break;
        }
        $this->_strategy = $cs;
    }
    //获取结果
    public function getResult($money){
        return $this->_strategy->acceptCash($money);
    }
    public function getResultAll($type, $num, $price){
        $this->setCashStrategy($type);
        return $this->getResult($num * $price);
    }

}

/*
 * 客户端类
 * 让客户端和业务逻辑尽可能的分离，降低客户端和业务逻辑算法的耦合，
 * 使业务逻辑的算法更具有可移植性
 */
class Client{

    public function main(){
        $total = 0;

        $factory = new Factory();

        // 购买数量
        $numA = 10;
        // 单价
        $priceA = 100;
        // 策略模式获取结果
        $totalA = $factory->getResultAll('normal', $numA, $priceA);
        $this->display('A', 'normal', $numA, $priceA, $totalA);

        // 购买数量
        $numB = 5;
        // 单价
        $priceB = 100;
        // 打折策略获取结果
        $totalB = $factory->getResultAll('rebate8', $numB, $priceB);
        $this->display('B', 'rebate8', $numB, $priceB, $totalB);

        // 购买数量
        $numC = 10;
        // 单价
        $priceC = 100;
        // 返利策略获取结果
        $totalC = $factory->getResultAll('return300to100', $numC, $priceC);
        $this->display('C', 'return300to100', $numC, $priceC, $totalC);
    }

    /**
     * 打印
     *
     * @param string $name 商品名
     * @param string $type 类型
     * @param int $num 数量
     * @param double $price 单价
     * @return double
     */
    public function display($name, $type, $num, $price, $total){
        echo date('Y-m-d H:i:s') . ",$name,[$type],num:$num,price:$price,total:$total<br>";
    }
}

/**
 * 程序入口
 */
function start(){
    $client = new Client();
    $client->main();
}

start();

?>

打印结果:
2018-10-09 11:17:30,A,[normal],num:10,price:100,total:1000
2018-10-09 11:17:30,B,[rebate8],num:5,price:100,total:400
2018-10-09 11:17:30,C,[return300to100],num:10,price:100,total:700