策略模式-商场促销-大话设计模式

ゝ一世哀愁。 2022-06-11 01:56 144阅读 0赞

类结构： ![1338464926_4157.jpg][]

//父类，商场结账的算法
    public interface SuperCash {
    	//得到算过后的结账金额
    	public double getcash(double cash);
    }

//正常的结账
    public class NormalCash implements SuperCash{
    
    	public double getcash(double cash) {
    		return cash;
    	}
    
    }

//对购买的货物进行打折的结账方式
    public class DiscountCash implements SuperCash{
    	private float moneyRebate;//打折的折扣
    	public DiscountCash(float moneyRebate){
    		this.moneyRebate=moneyRebate;
    	}
    	public double getcash(double cash) {
    		return moneyRebate*cash;
    	}
    
    }

//买五百送三百的这种方式结账
    public class ReturnCash implements SuperCash{
    	private float upcash;//五百
    	private float downcash;//三百
    	public ReturnCash(float upcash,float downcash){
    		this.upcash=upcash;
    		this.downcash=downcash;
    	}
    	public double getcash(double cash) {
    		double result=cash;
    		if(cash>=upcash){
    			result=cash-(Math.floor(cash/upcash)*downcash);
    		}
    		return result;
    	}
    }

//算法选择，并输出结果
    public class CashContext {
    	private SuperCash supercash;
    	public CashContext(String type){
    		//超市收款用多个算法类来进行使用和选择
    		if("正常收费".equals(type)){
    			
    			supercash=new NormalCash();
    		}else if(type.matches("打.+折")){
    			
    			float cash=Float.parseFloat(type.replaceAll("打(.+)折", "$1"));
    			supercash=new DiscountCash(cash/10);
    		}else if(type.matches("满.+送.+")){
    			
    			float cashup=Float.parseFloat(type.replaceAll("满(.+)送.+", "$1"));
    			float cashdown=Float.parseFloat(type.replaceAll("满.+送(.+)", "$1"));
    			supercash=new ReturnCash(cashup,cashdown);
    		}
    	}
    	public double getResult(double cash){
    		return supercash.getcash(cash);
    	}
    }

public class Test {
    	//策略模式：策略封装了变化
    	//也就是超市收款用多个算法类来进行使用和选择
    	public static void main(String[] args) {
    //		String type="正常收费";//输出:400.0
    //		String type="打8折";//输出:320.0000047683716
    		String type="满150送50";//输出:300.0
    		CashContext context = new CashContext(type);
    		double cash=context.getResult(400);
    		System.out.println(cash);
    	}
    }

[1338464926_4157.jpg]: https://img-my.csdn.net/uploads/201205/31/1338464926_4157.jpg