Java 23种设计模式之装饰器模式

1. 概念

动态的给一个对象添加一下额外的职责，就增加功能来说，
装饰模式比生成子类更加灵活。

2. 创建Person对象

public class Person {

private String name;

public Person(){}

public Person(String name){
this.name = name;
}

public String getName() {
return name;
}

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

public void show(){
System.out.println("装扮的 "+name);
}
}

3. 创建装饰类对象

public class PersonDecorator extends Person {

protected Person person;

public void decorate(Person person){
this.person = person;
}

public void  show(){
if(person != null){
person.show();
}
}
}

4. 创建具体装饰类对象

1.
public class Sneakers extends PersonDecorator{

@Override
public void show() {
System.out.print("破球鞋 ");
super.show();
}
}

2.
public class Suit extends PersonDecorator{

@Override
public void show() {
System.out.print("西装 ");
super.show();
}
}

3.
public class Tie extends PersonDecorator{

@Override
public void show() {
System.out.print("领带 ");
super.show();
}

@Override
public void show() {
System.out.print("皮鞋");
super.show();
}
}
等等.....

5. 测试类

@org.junit.Test
public void test(){

Person p = new Person("zlc");
System.out.println("第一种装扮 ：");
//球鞋
Sneakers sneakers = new Sneakers();
//T恤
TShirt tShirt = new TShirt();
//垮裤
Trouser trouser = new Trouser();

sneakers.decorate(p);

trouser.decorate(sneakers);

tShirt.decorate(trouser);

tShirt.show();
System.out.println();

System.out.println("第二种装扮 ：");
//皮鞋
LeatherShoes leatherShoes = new LeatherShoes();
//领带
Tie tie = new Tie();
//西装
Suit suit = new Suit();

leatherShoes.decorate(p);
tie.decorate(leatherShoes);
suit.decorate(tie);

suit.show();
System.out.println();
}

6.小结

装饰模式是为已有的功能动态的添加更多功能的一种方式
把类中的装饰功能从类中搬移去除，这样可以简化原有的类，可以有效的把
类的核心职责和装饰功能区分开了，而且可以去除类中重复的装饰逻辑。