命令模式

命令模式（Command Pattern）是一种数据驱动的设计模式，它属于行为型模式。请求以命令的形式包裹在对象中，并传给调用对象。调用对象寻找可以处理该命令的合适的对象，并把该命令传给相应的对象，该对象执行命令

实际案例

类信息概览：

类名 说明
Main.java 方法的总入口
SellStock.java 出售股票
Order.java 下单
BuyStock.java 购买股票
Stock.java 股票
StockCommand.java 股票命令行

定义

  • SellStock.java
package com.ryo.design.pattern.note.command;

/**
 * @author houbinbin
 * @version 1.0
 * @on 2017/8/13
 * @since 1.7
 */
public class SellStock implements Order {

    private Stock stock;

    public SellStock(Stock stock) {
        this.stock = stock;
    }

    @Override
    public void execute() {
        this.stock.sell();
    }
}
  • Order.java
package com.ryo.design.pattern.note.command;

/**
 * @author houbinbin
 * @version 1.0
 * @on 2017/8/13
 * @since 1.7
 */
public interface Order {

    /**
     * 执行
     */
    void execute();

}
  • BuyStock.java
package com.ryo.design.pattern.note.command;

/**
 * @author houbinbin
 * @version 1.0
 * @on 2017/8/13
 * @since 1.7
 */
public class BuyStock implements Order {

    private Stock stock;

    public BuyStock(Stock stock) {
        this.stock = stock;
    }

    @Override
    public void execute() {
        this.stock.buy();
    }
}
  • Stock.java
package com.ryo.design.pattern.note.command;

import lombok.Data;

/**
 * @author houbinbin
 * @version 1.0
 * @on 2017/8/13
 * @since 1.7
 */
@Data
public class Stock {

    private String name = "Common Stock";

    private int num = 10;

    public void buy() {
        System.out.println("Buy "+this);
    }

    public void sell() {
        System.out.println("Sell "+this);
    }


}
  • StockCommand.java
package com.ryo.design.pattern.note.command;

import java.util.LinkedList;
import java.util.List;

/**
 * @author houbinbin
 * @version 1.0
 * @on 2017/8/13
 * @since 1.7
 */
public class StockCommand {

    private List<Order> orderList = new LinkedList<>();


    public void addOrder(Order order) {
        this.orderList.add(order);
    }

    public void executeOrder() {
        for(Order order : this.orderList) {
            order.execute();
        }
    }

}

测试

  • Main.java
/*
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS HEADER.
 * Copyright (c) 2012-2018. houbinbini Inc.
 * design-pattern All rights reserved.
 */

package com.ryo.design.pattern.note.command;

/**
 * <p> </p>
 *
 * <pre> Created: 2018/5/21 下午7:27  </pre>
 * <pre> Project: design-pattern  </pre>
 *
 * @author houbinbin
 * @version 1.0
 * @since JDK 1.7
 */
public class Main {

    public static void main(String[] args) {
        Stock stock = new Stock();

        BuyStock buyStock = new BuyStock(stock);
        SellStock sellStock = new SellStock(stock);

        StockCommand command = new StockCommand();
        command.addOrder(buyStock);
        command.addOrder(sellStock);

        command.executeOrder();
    }

}
  • 测试结果
Buy Stock(name=Common Stock, num=10)
Sell Stock(name=Common Stock, num=10)

实现方式

UML & Code

UML

UML 图示如下

Code

代码地址

命令行模式

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