小白学习设计模式之装饰者模式

Posted 2020-11-01 我想回家

装饰者模式:
1.动态的将新功能附加到对象上,在对象功能扩展方面,他比继承更具有弹性
2.一个基类,多个分支

自我理解:
用人来举例,人有各个国家的人,这是一个分支,另一个分支就是穿着分支,冬季冷了添衣服就要添加衣服(这个黎姿不是特别合适)

视频中的例子:
使用饮品来举例,coffer有各个品种的咖啡,选定主coffer还可以选定辅料,继续添加辅料,最后计算总价0
下面是我的代码例子,视频中的例子放在下一章

package com.wz.decorate;

import java.math.BigDecimal;

/**
 * people类,描述和计算人衣服总价
 *
 * @author Administrator
 * @create 2018-04-22 13:47
 */
public abstract class PeopleMain {

    private String description;

    private BigDecimal money = new BigDecimal(0);

    public String getDescription() {
        return description;
    }

    public BigDecimal getMoney() {
        return money;
    }

    public void setDescription(String description) {
        this.description = description;
    }

    public void setMoney(BigDecimal money) {
        this.money = money;
    }

    public abstract BigDecimal cost();
}

package com.wz.decorate;

import java.math.BigDecimal;

/**
 * 国家人的分类
 *
 * @author Administrator
 * @create 2018-04-22 13:49
 */
public class People extends PeopleMain{

    @Override
    public BigDecimal cost() {
        return super.getMoney();
    }
}

package com.wz.decorate;

/**
 * 中国人
 *
 * @author Administrator
 * @create 2018-04-22 13:54
 */
public class China extends People {

    public China() {
        super.setDescription("China");
    }
}

package com.wz.decorate;

/**
 * 英国人
 *
 * @author Administrator
 * @create 2018-04-22 13:54
 */
public class Englisher extends People {

    public Englisher() {
        super.setDescription("Englisher");
    }
}

package com.wz.decorate;

import java.math.BigDecimal;

/**
 * 衣服类
 *
 * @author Administrator
 * @create 2018-04-22 13:58
 */
public class Clothing extends PeopleMain {

    private PeopleMain pm ;

    public Clothing(PeopleMain pm) {
        this.pm = pm;
    }

    @Override
    public String getDescription() {
        return super.getDescription() + "-" +pm.getDescription();
    }

    @Override
    public BigDecimal cost() {
        return super.getMoney().add(pm.cost());
    }
}

package com.wz.decorate;

import java.math.BigDecimal;

/**
 * 裤子
 *
 * @author Administrator
 * @create 2018-04-22 14:08
 */
public class Pants extends Clothing {

    public Pants(PeopleMain pm) {
        super(pm);
        super.setDescription("Pants");
        super.setMoney( new BigDecimal(150));
    }
}

package com.wz.decorate;

import java.math.BigDecimal;

/**
 * 鞋
 *
 * @author Administrator
 * @create 2018-04-22 14:06
 */
public class Shoe extends Clothing {

    public Shoe(PeopleMain pm) {
        super(pm);
        super.setDescription("Show");
        super.setMoney(new BigDecimal(600));
    }
}

package com.wz.decorate;

import java.math.BigDecimal;

/**
 * 外套
 *
 * @author Administrator
 * @create 2018-04-22 14:03
 */
public class Outerwear extends Clothing {

    public Outerwear(PeopleMain pm) {
        super(pm);
        super.setDescription("Outerwear");
        super.setMoney( new BigDecimal(300));
    }


}

package com.wz.decorate;

/**
 * 测试类
 *
 * @author Administrator
 * @create 2018-04-22 14:10
 */
public class TestMain {

    public static void main(String[] args) {
        PeopleMain pm ;
        pm = new Englisher();
        System.out.println(pm.getDescription());
        System.out.println(pm.cost());

        System.out.println("==========================================");

        pm = new China();
        pm = new Outerwear(pm);
        pm = new Pants(pm);
        pm = new Shoe(pm);
        System.out.println(pm.getDescription());
        System.out.println(pm.cost());

    }
}