设计模式——（装饰者模式）（组合模式）

设计模式——（装饰者模式）（组合模式）

装饰者模式

介绍

动态的将新功能附加到对象上。在对象功能扩展方面，它比继承更有弹性，装饰者模式也体现了开闭原则（ocp）。

实例：

有个咖啡店里面有各种咖啡和调料，让他们组合会非常麻烦，这时候出现了装饰者模式，咖啡作为主体，调料作为包装。

步骤：

1.先写Drink主类，里面写入描述和价格的参数，并get/set，并写入一个抽象方法cost(),谁继承谁实现

public abstract class Drink {public String des;private float price=0.0f;public String getDes() {return des;}public void setDes(String des) {this.des = des;}public float getPrice() {return price;}public void setPrice(float price) {this.price = price;}public abstract float cost();
}

2.创建咖啡类继承Drink

public class Coffee extends Drink{@Overridepublic float cost() {return super.getPrice();}
}

.创建详细咖啡类并通过set设置名称和价格

public class Espresso extends Coffee{public Espresso() {setDes(Espresso );setPrice(6.0f);}
}
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public class LongBlack extends Coffee{public LongBlack() {setDes(Long Black);setPrice(5.0f);}
}
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public class ShortBlack extends Coffee{public ShortBlack() {setDes(shotr black);setPrice(4.0f);}
}

4.创建一个装饰者，并通过组合的方式获得咖啡

public class Decorator extends Drink{private Drink obj;public Decorator(Drink obj) {=obj;}@Overridepublic float cost() {return super.getPrice()();}@Overridepublic String getDes() {return super.des super.getPrice()&&obj.getDes();}
}

5.创建调料类

public class Chocolate extends Decorator{public Chocolate(Drink obj) {super(obj);setDes(Chocolate);setPrice(.0f);}
}
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public class Milk extends Decorator{public Milk(Drink obj) {super(obj);setDes(Milk);setPrice(2.0f);}}

6.创建咖啡店

public class CoffeeStore {public static void main(String[] args) {//先点一份咖啡Drink longBlack = new LongBlack();println(fe yong=());println(mian shu=longBlack.getDes());//加调料longBlack=new Milk(longBlack);println(fe yong=());println(mian shu=longBlack.getDes());longBlack=new Chocolate(longBlack);println(fe yong=());println(mian shu=longBlack.getDes());longBlack=new Chocolate(longBlack);println(fe yong=());println(mian shu=longBlack.getDes());}
}

组合模式

实例：院校展示，学校——院系——专业

传统方案的问题：专业继承院系，院系继承学校。这是从大小组织上看的，但实际他们不存在这种关系。

介绍：

• 又叫部分整体模式，创建对象的树形结构。
• 组合模式用来表示整体层次
• 属于结构型模式
• 组合模式使得用户对单个对象和组合对象的访问具有一致性

代码：

先创建一个组织类，用来对学校，院系，专业的描述，让他们分别继承这个组织类

package com.kunposite;public abstract class OrganizationComponet {private String name;private String des;protected void add(OrganizationComponet organizationComponet) {//默认实现throw new UnsupportedOperationException();}protected void remove(OrganizationComponet organizationComponet) {//默认实现throw new UnsupportedOperationException();}public OrganizationComponet(String name, String des) {super(); = name;this.des = des;}public String getame() {return name;}public void setame(String name) { = name;}public String getDes() {return des;}public void setDes(String des) {this.des = des;}public abstract void print();
}

创建学校类，继承刚才的组织类，创建一个数组用来存放院系，重写add，remove方法

package com.kunposite;import java.util.ArrayList;
import java.util.List;public class University extends OrganizationComponet{List<OrganizationComponet> organizationComponets=new ArrayList<>();public University(String name, String des) {super(name, des);// TODO Auto-generated ctructor stub}@Overrideprotected void add(OrganizationComponet organizationComponet) {// TODO Auto-generated method stuborganizationComponets.add(organizationComponet);}@Overrideprotected void remove(OrganizationComponet organizationComponet) {// TODO Auto-generated method stuborganizationComponets.remove(organizationComponet);}@Overridepublic String getame() {// TODO Auto-generated method stubreturn super.getame();}@Overridepublic String getDes() {// TODO Auto-generated method stubreturn super.getDes();}@Overridepublic void print() {// TODO Auto-generated method stubprintln(==========getame()========);for (OrganizationComponet organizationComponet : organizationComponets) {organizationComponet.print();}}}

创建一个院系类，创建一个数组用来存放专业类

package com.kunposite;import java.util.ArrayList;
import java.util.List;public class College extends OrganizationComponet{List<OrganizationComponet> organizationComponets=new ArrayList<>();public College(String name, String des) {super(name, des);// TODO Auto-generated ctructor stub}@Overrideprotected void add(OrganizationComponet organizationComponet) {// TODO Auto-generated method stuborganizationComponets.add(organizationComponet);}@Overrideprotected void remove(OrganizationComponet organizationComponet) {// TODO Auto-generated method stuborganizationComponets.remove(organizationComponet);}@Overridepublic String getame() {// TODO Auto-generated method stubreturn super.getame();}@Overridepublic String getDes() {// TODO Auto-generated method stubreturn super.getDes();}@Overridepublic void print() {// TODO Auto-generated method stubprintln(==========getame()========);for (OrganizationComponet organizationComponet : organizationComponets) {organizationComponet.print();}}}

创建专业类，因为他是叶子节点，所以不用创建数组存放。

package com.kunposite;public class Department extends OrganizationComponet{public Department(String name, String des) {super(name, des);// TODO Auto-generated ctructor stub}@Overridepublic String getame() {// TODO Auto-generated method stubreturn super.getame();}@Overridepublic String getDes() {// TODO Auto-generated method stubreturn super.getDes();}@Overridepublic void print() {// TODO Auto-generated method stubprintln(getame());}}

创建Client主类方法测试

package com.kunposite;public class Client {public static void main(String[] args) {OrganizationComponet university = new University(AAA, 1111);OrganizationComponet college = new College(ji suan ji, ji suan ji);OrganizationComponet college2 = new College(guan li, guan li);college.add(new Department(ji ying, ji ying));college.add(new Department(ji wang, ji wang));college.add(new Department(ji suan, ji suan));college2.add(new Department(jiu dian, jiu dian));university.add(college);university.add(college2);university.print();}
}