Facade概述

玩具代码案例 - 订单服务门面

门面角色

IOrderService

package online.javabook.gof.structural.patterns5.facde.mall.service.api;
public interface IOrderService {
    void submitOrder();
}

OrderService

package online.javabook.gof.structural.patterns5.facde.mall.service.impl;

import online.javabook.gof.structural.patterns5.facde.mall.repository.api.ICartRepository;
import online.javabook.gof.structural.patterns5.facde.mall.repository.api.IExpressRepository;
import online.javabook.gof.structural.patterns5.facde.mall.repository.api.IPayRepository;
import online.javabook.gof.structural.patterns5.facde.mall.repository.impl.CartRepository;
import online.javabook.gof.structural.patterns5.facde.mall.repository.impl.ExpressRepository;
import online.javabook.gof.structural.patterns5.facde.mall.repository.impl.PayRepository;
import online.javabook.gof.structural.patterns5.facde.mall.service.api.IOrderService;

public class OrderService implements IOrderService {

    private ICartRepository cartRepository = new CartRepository();

    private IPayRepository payRepository = new PayRepository();

    private IExpressRepository expressRepository = new ExpressRepository();

    @Override
    public void submitOrder() {
        cartRepository.buy();
        payRepository.pay();
        expressRepository.ship();
    }
}

被聚合的角色

ICartRepository

package online.javabook.gof.structural.patterns5.facde.mall.repository.api;

public interface ICartRepository {
    void buy();
}

package online.javabook.gof.structural.patterns5.facde.mall.repository.impl;

import online.javabook.gof.structural.patterns5.facde.mall.repository.api.ICartRepository;

public class CartRepository implements ICartRepository {
    @Override
    public void buy() {
        System.out.println("buy.....");
    }
}

IExpressRepository

package online.javabook.gof.structural.patterns5.facde.mall.repository.api;

public interface IExpressRepository {

    void ship();
}

package online.javabook.gof.structural.patterns5.facde.mall.repository.impl;

import online.javabook.gof.structural.patterns5.facde.mall.repository.api.IExpressRepository;

public class ExpressRepository implements IExpressRepository {
    @Override
    public void ship() {
        System.out.println("ship.....");
    }
}

IPayRepository

package online.javabook.gof.structural.patterns5.facde.mall.repository.api;

public interface IPayRepository {
    void pay();
}

package online.javabook.gof.structural.patterns5.facde.mall.repository.impl;

import online.javabook.gof.structural.patterns5.facde.mall.repository.api.IPayRepository;

public class PayRepository implements IPayRepository {
    @Override
    public void pay() {
        System.out.println("pay.....");
    }
}

不基于门面模式的实现

Main

package online.javabook.gof.structural.patterns5.facde.mall.app.bad;

import online.javabook.gof.structural.patterns5.facde.mall.repository.api.ICartRepository;
import online.javabook.gof.structural.patterns5.facde.mall.repository.api.IExpressRepository;
import online.javabook.gof.structural.patterns5.facde.mall.repository.api.IPayRepository;
import online.javabook.gof.structural.patterns5.facde.mall.repository.impl.CartRepository;
import online.javabook.gof.structural.patterns5.facde.mall.repository.impl.ExpressRepository;
import online.javabook.gof.structural.patterns5.facde.mall.repository.impl.PayRepository;

public class Main {
    public static void main(String[] args) {

        ICartRepository cartRepository = new CartRepository();
        IPayRepository payRepository = new PayRepository();
        IExpressRepository expressRepository = new ExpressRepository();

        cartRepository.buy();
        payRepository.pay();
        expressRepository.ship();
    }
}

基于门面模式的实现

Main

package online.javabook.gof.structural.patterns5.facde.mall.app.good;

import online.javabook.gof.structural.patterns5.facde.mall.service.api.IOrderService;
import online.javabook.gof.structural.patterns5.facde.mall.service.impl.OrderService;

public class Main {
    public static void main(String[] args) {

        IOrderService orderService = new OrderService();
        orderService.submitOrder();
    }
}