11,装饰模式-孙悟空的六神装

一,前言

7种结构型设计模式:桥接模式,适配器模式,装饰模式,组合模式,享元模式,外观模式,代理模式

上篇我们说了外观模式:提供一个统一接口来访问子系统中的一群接口
外观定义了一个高层接口,让子系统更容易使用

开发中我们为一个对象添加新行为通常会采用继承的方式
但通常这样做会导致子类泛滥的结果也就是我们常说的类爆炸,为后续的维护带来不便
本着"开放-关闭"的设计原则,我们希望在不修改原有代码的情况下,为对象赋予新的职责

这篇的结构型设计模式就可以做到,它就是装饰模式,也叫做装饰器或装饰者模式

二,装饰模式简介

1,简介:

装饰者模式:动态地将责任附加到对象上,在不修改任何底层代码的情况下,为对象赋予新的职责

2,装饰模式类图:

从类图中我们可以看到:
装饰者和被装饰者(组件)拥有相同的接口,所以装饰者能够取代被装饰者
装饰者与组件进行组合时,通过对象组合为组件加入新的行为
所以装饰者模式能在不创建更多子类的情况下，实现对象功能的拓展

这也正是组合的威力所在,多用组合少用继承
如果依赖继承,类的行为只能在编译时静态决定,行为来自超类或子类进行覆盖
组合可以把装饰器和组件进行混合,而且是在运行时才决定具体行为

3,装饰模式中的角色:

抽象组件(Component)角色：给出一个抽象接口，规范准备接收附加责任的对象。
具体组件(ConcreteComponent)角色：定义一个将要接收附加责任的类。

装饰(Decorator)角色：持有一个组件对象(Component)的实例，并定义一个与抽象构件接口一致的接口。
具体装饰(ConcreteDecorator)角色：负责为组件对象赋予新职责。

三,装饰模式场景

我们选取一个比较适合装饰模式的场景来对这个模式进行学习
最后我选择了游戏中为角色添加装备来获得属性加成的例子
那么这篇的主题又回到了大家感兴趣的游戏话题上
我们就来看看"王者荣耀"中孙悟空这个英雄的六神装
ps:这里对英雄和装备属性做了修改,和真实游戏中的属性不一致,望谅解!

我们的场景是这样的:
1,创建一个抽象组件Hero(即抽象组件角色),通过继承此类创建具体英雄,此类定义了英雄属性
2,通过继承Hero类创建具体英雄(孙悟空),并针对英雄个性化做属性调整
3,创建一个抽象装备类Equipment(即抽象装饰角色),继承自组件Hero,通过继承此类创建具体装备,此类需定义装饰新功能的接口,以重写为新的功能供外部调用
4,通过继承Equipment类创建具体装备类,此类需持有一个具体英雄(Hero)的引用,重写接口时对此引用信息做修改,以实现功能的变更和添加
5,使用4的方式创建6件装备,并逐一为英雄装饰,打印日志查看装饰后的英雄属性

四,装饰模式例子

1,创建抽象组件Hero,即抽象组件角色,定义英雄属性

package com.brave.decorator.pesticide.hero;

/**
* 抽象英雄
*  -每个具体英雄都继承自此类
*  -默认属性数值均为100暴击率0%暴击效果2倍
*
* @author Brave
*
*/
public abstract class Hero {

private String name = "";   // 名称
private double HP = 100;    // 生命值
private double MP = 100;    // 魔法值
private double ATK = 100;   // 攻击力
private double DEF = 100;   // 防御力
private double CRT = 0;     // 暴击率加成
private double CRTE = 2;    // 暴击效果
private double MS = 0;      // 移动速度加成
private double AB = 0;      // 破甲加成
private String equipment = "";  // 装备

public String getName() {
return name;
}

public void setName(String name) {
this.name = name;
}

public double getHP() {
return HP;
}

public void setHP(double hP) {
HP = hP;
}

public double getMP() {
return MP;
}

public void setMP(double mP) {
MP = mP;
}

public double getATK() {
return ATK;
}

public void setATK(double aTK) {
ATK = aTK;
}

public double getDEF() {
return DEF;
}

public void setDEF(double dEF) {
DEF = dEF;
}

public double getCRT() {
return CRT;
}

public void setCRT(double cRT) {
CRT = cRT;
}

public double getCRTE() {
return CRTE;
}

public void setCRTE(double cRTE) {
CRTE = cRTE;
}

public double getMS() {
return MS;
}

public void setMS(double mS) {
MS = mS;
}

public String getEquipment() {
return equipment;
}

public void setEquipment(String equipment) {
this.equipment = equipment;
}

public double getAB() {
return AB;
}

public void setAB(double aB) {
AB = aB;
}

public void printHeroAttr() {
System.out.println("name = " + name);
System.out.println("生命值:HP = " + HP);
System.out.println("魔法值:MP = " + MP);
System.out.println("攻击力:ATK = " + ATK);
System.out.println("防御力:DEF = " + DEF);
System.out.println("暴击率加成:CRT = " + CRT);
System.out.println("暴击效果:CRTE = " + CRTE);
System.out.println("移动速度加成:MS = " + MS);
if(!equipment.equals(""))System.out.println("装备:equipment = " + equipment);
}

}

2,通过继承Hero类创建具体英雄孙悟空,针对英雄个性化做属性调整

package com.brave.decorator.pesticide.hero;

/**
* 具体英雄-孙悟空
* 初始暴击率为20%,暴击伤害150%;
*
* @author Brave
*
*/
public class MonkeyKing extends Hero {

public MonkeyKing() {
setName("孙悟空");
setCRT(0.2);
setCRTE(1.5);
}

}

3,继承自组件Hero,创建抽象装备类Equipment,定义装饰新功能的接口,以重写为新的功能供外部调用

package com.brave.decorator.pesticide.equipment;

import com.brave.decorator.pesticide.hero.Hero;

/**
* 抽象装备
*  -每个具体装备都继承自此类
*
* @author Brave
*
*/
public abstract class Equipment extends Hero{

// 强制重写-装备名称
public abstract String getName();

// 输出准备此件装备后的所有装备信息
public abstract double getHP();
public abstract double getMP();
public abstract double getATK();
public abstract double getDEF();
public abstract double getCRT();
public abstract double getCRTE();
public abstract double getMS();
public abstract double getAB();
public abstract String getEquipment();

// 强制重写-输出装备此件装备后的全部属性
public abstract void printHeroAttr();

}

4,通过继承Equipment类创建具体装备类

此类持有一个具体英雄(Hero)的引用,重写接口时对此引用信息做修改,以实现功能的变更和添加

创建6件装备:
鞋子:100移速
无尽之刃:50%暴击+50%暴击效果
破甲弓:100攻击+100破甲
冰痕之握:100防御+100魔法
装饰泣血之刃:100攻击+100生命
破军:200攻击

1)鞋子:增加100点移动速度

package com.brave.decorator.pesticide.equipment;

import com.brave.decorator.pesticide.hero.Hero;

/**
* 鞋子:增加100点移动速度
* @author Brave
*
*/
public class Shoes extends Equipment {

private Hero hero;

public Shoes(Hero hero) {
this.hero = hero;
}

@Override
public void printHeroAttr() {
System.out.println("name = " + getName());
System.out.println("生命值:HP = " + getHP());
System.out.println("魔法值:MP = " + getMP());
System.out.println("攻击力:ATK = " + getATK());
System.out.println("防御力:DEF = " + getDEF());
System.out.println("暴击率加成:CRT = " + getCRT());
System.out.println("暴击效果:CRTE = " + getCRTE());
System.out.println("移动速度加成:MS = " + getMS());
System.out.println("破甲加成:AB = " + getAB());
System.out.println(getEquipment().equals("") ? "" : "装备:equipment = " + getEquipment());
}

@Override
public String getName() {
return "鞋子";
}

@Override
public double getHP() {
return hero.getHP();
}

@Override
public double getMP() {
return hero.getMP();
}

@Override
public double getATK() {
return hero.getATK();
}

@Override
public double getDEF() {
return hero.getDEF();
}

@Override
public double getCRT() {
return hero.getCRT();
}

@Override
public double getCRTE() {
return hero.getCRTE();
}

@Override
public double getMS() {
return hero.getMS() + 100;
}

@Override
public String getEquipment() {
return hero.getEquipment() + getName() + ",";
}

@Override
public double getAB() {
return hero.getAB();
}

}

2)无尽之刃:50%暴击+50%暴击效果

package com.brave.decorator.pesticide.equipment;

import com.brave.decorator.pesticide.hero.Hero;

/**
* 无尽之刃:增加暴击率50%.暴击效果50%
* @author Brave
*
*/
public class InfinitySword extends Equipment {

private Hero hero;

public InfinitySword(Hero hero) {
this.hero = hero;
}

@Override
public void printHeroAttr() {
System.out.println("name = " + getName());
System.out.println("生命值:HP = " + getHP());
System.out.println("魔法值:MP = " + getMP());
System.out.println("攻击力:ATK = " + getATK());
System.out.println("防御力:DEF = " + getDEF());
System.out.println("暴击率加成:CRT = " + getCRT());
System.out.println("暴击效果:CRTE = " + getCRTE());
System.out.println("移动速度加成:MS = " + getMS());
System.out.println("破甲加成:AB = " + getAB());
System.out.println(getEquipment().equals("") ? "" : "装备:equipment = " + getEquipment());
}

@Override
public String getName() {
return "无尽之刃";
}

@Override
public double getHP() {
return hero.getHP();
}

@Override
public double getMP() {
return hero.getMP();
}

@Override
public double getATK() {
return hero.getATK();
}

@Override
public double getDEF() {
return hero.getDEF();
}

@Override
public double getCRT() {
return hero.getCRT() + 0.5;
}

@Override
public double getCRTE() {
return hero.getCRTE() + 0.5;
}

@Override
public double getMS() {
return hero.getMS();
}

@Override
public String getEquipment() {
return hero.getEquipment() + getName() + ",";
}

@Override
public double getAB() {
return hero.getAB();
}

}

3)破甲弓:100攻击+100破甲

package com.brave.decorator.pesticide.equipment;

import com.brave.decorator.pesticide.hero.Hero;

/**
* 破甲弓:100攻击+100破甲
* @author Brave
*
*/
public class ArmorBow extends Equipment {

private Hero hero;

public ArmorBow(Hero hero) {
this.hero = hero;
}

@Override
public void printHeroAttr() {
System.out.println("name = " + getName());
System.out.println("生命值:HP = " + getHP());
System.out.println("魔法值:MP = " + getMP());
System.out.println("攻击力:ATK = " + getATK());
System.out.println("防御力:DEF = " + getDEF());
System.out.println("暴击率加成:CRT = " + getCRT());
System.out.println("暴击效果:CRTE = " + getCRTE());
System.out.println("移动速度加成:MS = " + getMS());
System.out.println("破甲加成:AB = " + getAB());
System.out.println(getEquipment().equals("") ? "" : "装备:equipment = " + getEquipment());
}

@Override
public String getName() {
return "破甲弓";
}

@Override
public double getHP() {
return hero.getHP();
}

@Override
public double getMP() {
return hero.getMP();
}

@Override
public double getATK() {
return hero.getATK() + 100;
}

@Override
public double getDEF() {
return hero.getDEF();
}

@Override
public double getCRT() {
return hero.getCRT();
}

@Override
public double getCRTE() {
return hero.getCRTE();
}

@Override
public double getMS() {
return hero.getMS();
}

@Override
public String getEquipment() {
return hero.getEquipment() + getName() + ",";
}

@Override
public double getAB() {
return hero.getAB() + 100;
}

}

4)冰痕之握:100防御+100魔法

package com.brave.decorator.pesticide.equipment;

import com.brave.decorator.pesticide.hero.Hero;

/**
* 复活甲:100防御+100魔法值
* @author Brave
*
*/
public class IceMarkGrip extends Equipment {

private Hero hero;

public IceMarkGrip(Hero hero) {
this.hero = hero;
}

@Override
public void printHeroAttr() {
System.out.println("name = " + getName());
System.out.println("生命值:HP = " + getHP());
System.out.println("魔法值:MP = " + getMP());
System.out.println("攻击力:ATK = " + getATK());
System.out.println("防御力:DEF = " + getDEF());
System.out.println("暴击率加成:CRT = " + getCRT());
System.out.println("暴击效果:CRTE = " + getCRTE());
System.out.println("移动速度加成:MS = " + getMS());
System.out.println("破甲加成:AB = " + getAB());
System.out.println(getEquipment().equals("") ? "" : "装备:equipment = " + getEquipment());
}

@Override
public String getName() {
return "冰痕之握";
}

@Override
public double getHP() {
return hero.getHP();
}

@Override
public double getMP() {
return hero.getMP() + 100;
}

@Override
public double getATK() {
return hero.getATK();
}

@Override
public double getDEF() {
return hero.getDEF() + 100;
}

@Override
public double getCRT() {
return hero.getCRT();
}

@Override
public double getCRTE() {
return hero.getCRTE();
}

@Override
public double getMS() {
return hero.getMS();
}

@Override
public String getEquipment() {
return hero.getEquipment() + getName() + ",";
}

@Override
public double getAB() {
return hero.getAB();
}

}

5)泣血之刃:100攻击+100生命

package com.brave.decorator.pesticide.equipment;

import com.brave.decorator.pesticide.hero.Hero;

/**
* 泣血之刃:100攻击+100生命值
* @author Brave
*
*/
public class BloodSword extends Equipment {

private Hero hero;

public BloodSword(Hero hero) {
this.hero = hero;
}

@Override
public void printHeroAttr() {
System.out.println("name = " + getName());
System.out.println("生命值:HP = " + getHP());
System.out.println("魔法值:MP = " + getMP());
System.out.println("攻击力:ATK = " + getATK());
System.out.println("防御力:DEF = " + getDEF());
System.out.println("暴击率加成:CRT = " + getCRT());
System.out.println("暴击效果:CRTE = " + getCRTE());
System.out.println("移动速度加成:MS = " + getMS());
System.out.println("破甲加成:AB = " + getAB());
System.out.println(getEquipment().equals("") ? "" : "装备:equipment = " + getEquipment());
}

@Override
public String getName() {
return "泣血之刃";
}

@Override
public double getHP() {
return hero.getHP() + 100;
}

@Override
public double getMP() {
return hero.getMP();
}

@Override
public double getATK() {
return hero.getATK() + 100;
}

@Override
public double getDEF() {
return hero.getDEF();
}

@Override
public double getCRT() {
return hero.getCRT();
}

@Override
public double getCRTE() {
return hero.getCRTE();
}

@Override
public double getMS() {
return hero.getMS();
}

@Override
public String getEquipment() {
return hero.getEquipment() + getName() + ",";
}

@Override
public double getAB() {
return hero.getAB();
}

}

6)破军:200攻击

package com.brave.decorator.pesticide.equipment;

import com.brave.decorator.pesticide.hero.Hero;

/**
* 破军:200攻击
* @author Brave
*
*/
public class Breach extends Equipment {

private Hero hero;

public Breach(Hero hero) {
this.hero = hero;
}

@Override
public void printHeroAttr() {
System.out.println("name = " + getName());
System.out.println("生命值:HP = " + getHP());
System.out.println("魔法值:MP = " + getMP());
System.out.println("攻击力:ATK = " + getATK());
System.out.println("防御力:DEF = " + getDEF());
System.out.println("暴击率加成:CRT = " + getCRT());
System.out.println("暴击效果:CRTE = " + getCRTE());
System.out.println("移动速度加成:MS = " + getMS());
System.out.println("破甲加成:AB = " + getAB());
System.out.println(getEquipment().equals("") ? "" : "装备:equipment = " + getEquipment());
}

@Override
public String getName() {
return "破甲弓";
}

@Override
public double getHP() {
return hero.getHP();
}

@Override
public double getMP() {
return hero.getMP();
}

@Override
public double getATK() {
return hero.getATK() + 200;
}

@Override
public double getDEF() {
return hero.getDEF();
}

@Override
public double getCRT() {
return hero.getCRT();
}

@Override
public double getCRTE() {
return hero.getCRTE();
}

@Override
public double getMS() {
return hero.getMS();
}

@Override
public String getEquipment() {
return hero.getEquipment() + getName() + ",";
}

@Override
public double getAB() {
return hero.getAB();
}

}

5,测试装饰模式,逐一为英雄装饰6件装备,打印日志查看装饰后的英雄属性

package com.brave.decorator.pesticide;

import com.brave.decorator.pesticide.equipment.ArmorBow;
import com.brave.decorator.pesticide.equipment.BloodSword;
import com.brave.decorator.pesticide.equipment.Breach;
import com.brave.decorator.pesticide.equipment.IceMarkGrip;
import com.brave.decorator.pesticide.equipment.InfinitySword;
import com.brave.decorator.pesticide.equipment.Shoes;
import com.brave.decorator.pesticide.hero.Hero;
import com.brave.decorator.pesticide.hero.MonkeyKing;

/**
* 测试装饰模式
*
* 在不修改任何底层代码的情况下.为对象赋予新的职责
* 装饰者模式:动态地将责任附加到对象上,若要拓展功能,装饰者提供了比继承更有弹性的替代方案
*
* @author Brave
*
*/
public class Client {

public static void main(String[] args) {

System.out.println("*****************初始化英雄******************");
Hero hero = new MonkeyKing();
hero.printHeroAttr();

System.out.println("*****************装饰鞋子:100移速******************");
Hero shoes = new Shoes(hero);
shoes.printHeroAttr();
System.out.println("*****************装饰无尽之刃:50%暴击+50%暴击效果******************");
Hero infinitySword = new InfinitySword(shoes);
infinitySword.printHeroAttr();
System.out.println("*****************装饰破甲弓:100攻击+100破甲******************");
Hero armorBow = new ArmorBow(infinitySword);
armorBow.printHeroAttr();
System.out.println("*****************装饰冰痕之握:100防御+100魔法******************");
Hero iceMarkGrip = new IceMarkGrip(armorBow);
iceMarkGrip.printHeroAttr();
System.out.println("*****************装饰泣血之刃:100攻击+100生命******************");
Hero bloodSword = new BloodSword(iceMarkGrip);
bloodSword.printHeroAttr();
System.out.println("*****************装饰破军:200攻击******************");
Hero breach = new Breach(bloodSword);
breach.printHeroAttr();
}

}

6,打印日志输出,查看属性

*****************初始化英雄******************
name = 孙悟空
生命值:HP = 100.0
魔法值:MP = 100.0
攻击力:ATK = 100.0
防御力:DEF = 100.0
暴击率加成:CRT = 0.2
暴击效果:CRTE = 1.5
移动速度加成:MS = 0.0
*****************装饰鞋子:100移速******************
name = 鞋子
生命值:HP = 100.0
魔法值:MP = 100.0
攻击力:ATK = 100.0
防御力:DEF = 100.0
暴击率加成:CRT = 0.2
暴击效果:CRTE = 1.5
移动速度加成:MS = 100.0
破甲加成:AB = 0.0
装备:equipment = 鞋子,
*****************装饰无尽之刃:50%暴击+50%暴击效果******************
name = 无尽之刃
生命值:HP = 100.0
魔法值:MP = 100.0
攻击力:ATK = 100.0
防御力:DEF = 100.0
暴击率加成:CRT = 0.7
暴击效果:CRTE = 2.0
移动速度加成:MS = 100.0
破甲加成:AB = 0.0
装备:equipment = 鞋子,无尽之刃,
*****************装饰破甲弓:100攻击+100破甲******************
name = 破甲弓
生命值:HP = 100.0
魔法值:MP = 100.0
攻击力:ATK = 200.0
防御力:DEF = 100.0
暴击率加成:CRT = 0.7
暴击效果:CRTE = 2.0
移动速度加成:MS = 100.0
破甲加成:AB = 100.0
装备:equipment = 鞋子,无尽之刃,破甲弓,
*****************装饰冰痕之握:100防御+100魔法******************
name = 冰痕之握
生命值:HP = 100.0
魔法值:MP = 200.0
攻击力:ATK = 200.0
防御力:DEF = 200.0
暴击率加成:CRT = 0.7
暴击效果:CRTE = 2.0
移动速度加成:MS = 100.0
破甲加成:AB = 100.0
装备:equipment = 鞋子,无尽之刃,破甲弓,冰痕之握,
*****************装饰泣血之刃:100攻击+100生命******************
name = 泣血之刃
生命值:HP = 200.0
魔法值:MP = 200.0
攻击力:ATK = 300.0
防御力:DEF = 200.0
暴击率加成:CRT = 0.7
暴击效果:CRTE = 2.0
移动速度加成:MS = 100.0
破甲加成:AB = 100.0
装备:equipment = 鞋子,无尽之刃,破甲弓,冰痕之握,泣血之刃,
*****************装饰破军:200攻击******************
name = 破甲弓
生命值:HP = 200.0
魔法值:MP = 200.0
攻击力:ATK = 500.0
防御力:DEF = 200.0
暴击率加成:CRT = 0.7
暴击效果:CRTE = 2.0
移动速度加成:MS = 100.0
破甲加成:AB = 100.0
装备:equipment = 鞋子,无尽之刃,破甲弓,冰痕之握,泣血之刃,破甲弓,

四,装饰模式的优点与缺点

装饰模式的优点:
1,装饰模式与继承的目的都是扩展对象功能，但装饰模式比继承更加灵活性。
装饰模式允许系统动态决定添加装饰,或移除装饰
继承关系是静态的,在系统运行前决定
2,可以灵活的"改造"对象,使用不同装饰器或改变排列组合顺序,实现多种组合

装饰模式的缺点:
装饰模式使用组合实现新功能的添加,相比继承的实现使用了较少的类
但由于装饰模式的特性,会产生比使用继承关系更多的对象
而这些对象都很相似,数量也较多,所以加大了系统错误的排查难度

模式到这里就简单的说完了,先备注一些后面要加入的部分

java中使用的装饰模式-IO

装饰模式和其他模式的区别,例如和适配器