二十：职责链模式详解（类似于spring的hangler处理请求）

package com.chain;

import java.util.Map;

//订单类（相当于request，其实就是封装一个请求）
public class Order {

    private int x;
    private int y;
    private Map order;
    
    public Order(int x, int y, Map order) {
        super();
        this.x = x;
        this.y = y;
        this.order = order;
    }

    public int getX() {
        return x;
    }

    public void setX(int x) {
        this.x = x;
    }

    public int getY() {
        return y;
    }

    public void setY(int y) {
        this.y = y;
    }

    public Map getOrder() {
        return order;
    }

    public void setOrder(Map order) {
        this.order = order;
    }
    
}

package com.chain;
//分店接口（相当于Hanlder）
public interface Subbranch {

    void setSuccessor(Subbranch subbranch);
    
    boolean handleOrder(Order order);
    
}

package com.chain;

import java.util.Collections;
import java.util.Map;

//麦当劳分店
public class McSubbranch implements Subbranch{
    
    private final static int MIN_DISTANCE = 500;//假设是500米以内送餐
    
    private static int count;//类计数
    
    private final int number;//分店号
    
    private int x;//分店的横坐标，用于判断距离
    
    private int y;//分店的纵坐标，用于判断距离
    
    private Map menu;//菜单
    
    private Subbranch nextSubbranch;//下一家分店
    
    public McSubbranch(int x, int y, Map menu) {
        super();
        this.x = x;
        this.y = y;
        this.menu = menu;
        number = ++count;
    }
    //设置下一家分店
    public void setSuccessor(Subbranch subbranch) {
        this.nextSubbranch = subbranch;
    }
    //按照职责链处理订单
    public boolean handleOrder(Order order){
        //如果距离小于500米并且订单中的食物不缺货，则订单成功，否则失败
        if (CommonUtils.getDistance(order.getX(), order.getY(), this.x, this.y)  getMenu() {
        return Collections.unmodifiableMap(menu);
    }
    
    public Subbranch getNextSubbranch() {
        return nextSubbranch;
    }
    
    public String toString() {
        return "麦当劳分店第" + number + "个";
    }
    
    
}

package com.chain;

import java.util.HashMap;
import java.util.Map;

public class Client {

    public static void main(String[] args) {
        //假设初始菜单都是以下这些东西
        Map menu = new HashMap();
        menu.put("汉堡", 5);
        menu.put("薯条", 5);
        menu.put("可乐", 5);
        menu.put("雪碧", 5);
        //假设有5个分店
        Subbranch mcSubbranch1 = new McSubbranch(0, 0, new HashMap(menu));
        Subbranch mcSubbranch2 = new McSubbranch(100, 120, new HashMap(menu));
        Subbranch mcSubbranch3 = new McSubbranch(-100, -120, new HashMap(menu));
        Subbranch mcSubbranch4 = new McSubbranch(1000, 20, new HashMap(menu));
        Subbranch mcSubbranch5 = new McSubbranch(-500, 0, new HashMap(menu));
        
        //以下设置职责链
        mcSubbranch4.setSuccessor(mcSubbranch5);
        mcSubbranch3.setSuccessor(mcSubbranch4);
        mcSubbranch2.setSuccessor(mcSubbranch3);
        mcSubbranch1.setSuccessor(mcSubbranch2);
        //小左开始订餐，假设小左的坐标是900,20 
        Map order = new HashMap();
        order.put("汉堡", 2);
        order.put("可乐", 1);
        order.put("薯条", 1);
        
        print(mcSubbranch1);
        System.out.println("------------------------------------------");
        
        //小左开始订餐，直接找mcSubbranch1的这一家分店订餐即可
        mcSubbranch1.handleOrder(new Order(900, 20, order));
        
        System.out.println("------------------------------------------");
        print(mcSubbranch1);
    }
    
    public static void print(Subbranch subbranch){
        if (subbranch == null ) {
            return;
        }
        do {
            if (subbranch instanceof McSubbranch) {
                System.out.println("[" + subbranch + "]的菜单:" + ((McSubbranch) subbranch).getMenu());
            }
        } while ((subbranch = ((McSubbranch) subbranch).getNextSubbranch()) != null);
    }
    
}