设计模式学习笔记（23）——装饰模式实现

装饰模式
一、小菜扮靓第一版

class Person{
	private String name;
	public Person(String name) {
		this.name=name;
	}
	public void WearTShirts(){
		System.out.print("大T恤");
	}
	public void WearBigTrouser() {
		System.out.print("垮裤");
	}
	public void WearSneakers() {
		System.out.print("破球鞋");
	}
	public void WearSuit() {
		System.out.print("西装");
	}
	public void WearTie() {
		System.out.print("领带");
	}
	public void WearLeatherShoes() {
		System.out.print("皮鞋");
	}
	public void Show() {
		System.out.printf("装扮的"+name);
	}
}
public class Main{
	public static void main(String[] args){
		Person xc=new Person("小菜");
		System.out.printf("\n第一种装扮：");
		xc.WearTShirts();
		xc.WearBigTrouser();
		xc.WearSneakers();
		xc.Show();
		System.out.printf("\n第二种装扮：");
		xc.WearSuit();
		xc.WearTie();
		xc.WearLeatherShoes();
		xc.Show();
	}
}

增加装扮，需要修改Person类，而这样就违反了开放封闭原则。
二、小菜扮靓第二版

class Person{
	private String name;
	public Person(String name) {
		this.name=name;
	}
	
	public void Show() {
		System.out.printf("装扮的"+name);
	}
}
abstract class Finery{
	public abstract void Show();
}
class TShirts extends Finery{
	public void Show() {
	System.out.print("大T恤");}
}
class BigTrouser extends Finery{
	public void Show() {
	System.out.print("垮裤");}
}
class Sneakers extends Finery {
	public void Show() {
	System.out.print("破球鞋");}
}
class Suit extends Finery {
	public void Show() {
	System.out.print("西装");}
}
class Tie extends Finery {
	public void Show() {
	System.out.print("领带");}
}
class LeatherShoes extends Finery {
	public void Show() {
	System.out.print("皮鞋");}
}
public class Main{
	public static void main(String[] args){
		Person xc=new Person("小菜");
		System.out.printf("\n第一种装扮：");
		Finery dtx=new TShirts();
		Finery kk=new BigTrouser();
		Finery pqx=new Sneakers();
		dtx.Show();
		kk.Show();
		pqx.Show();
		xc.Show();
		System.out.printf("\n第二种装扮：");
		Finery xz=new Suit();
		Finery ld=new Tie();
		Finery px=new LeatherShoes();
		xz.Show();
		ld.Show();
		px.Show();
		xc.Show();
		
	}
}

三、装饰模式
Component是定义一个对象接口，可以给这些对象动态地添加职责。ConcreteComponent是定义了一个具体的对象，也可以给这个对象添加一些职责。Decorater，装饰抽象类，继承了Component，从外来类扩展Component类的功能，但对Component来说，是无需知道Decorator的存在的。至于ConcreteDecorator就是具体的装饰对象，起到给Component添加职责的功能。

abstract class Component{
	public abstract void Operation();
}
class ConcreteComponent extends Component{
 
	@Override
	public void Operation() {
		// TODO Auto-generated method stub
		System.out.println("具体对象操作");
	}
	
}
abstract class Decorator extends Component{
	protected Component component;
	public void SetComponent(Component component) {
		this.component=component;
	}
	public void Operation() {
		if(component!=null) {//执行的是成员component的Operation()
			component.Operation();
		}
	}
}
class ConcreteDecoratorA extends Decorator{
	private String addedState;//区别于A的独有方法
	public void Operation() {
		super.Operation();
		addedState="New State";
		System.out.println("具体装饰对象A的操作");
	}
}
class ConcreteDecoratorB extends Decorator{
	private void addedBehavior() {//区别于A的独有方法
		System.out.println("AddedBehavior Operation");
	}
	public void Operation() {
		super.Operation();
		addedBehavior();
		System.out.println("具体装饰对象B的操作");
	}
}
public  class Main{
	public static void main(String[] args){
	ConcreteComponent c=new ConcreteComponent();
	ConcreteDecoratorA d1=new ConcreteDecoratorA();
	ConcreteDecoratorB d2=new ConcreteDecoratorB();
	d1.SetComponent(c);
	d2.SetComponent(d1);
	d2.Operation();
	
	}
}

装饰的方法是：首先用ConcreteCompotent实例化对象c，然后用ConcreteDecoratorA的实例化对象d1来包装c，再用ConcreteDecoratorB的对象d2包装d1,最终执行d2的Operation（）。

四、小菜扮靓第三版

package operation;
abstract class Component{
	public abstract void Show();
}
class Person extends Component{
	public Person() {}
	private String name;
	public Person(String name) {
		this.name=name;
	}
	@Override
	public void Show() {
		// TODO Auto-generated method stub
		System.out.println("装扮的"+name);
	}
	
}

class Finery extends Component{
	protected Component component;
	public void Decorate(Component component) {
		this.component=component;
	}
	@Override
	public void Show() {
		// TODO Auto-generated method stub
		if(component!=null) {
			component.Show();
		}
	}
}

class TShirts extends Finery{
	public void Show() {
		System.out.println("大T恤"); super.Show();
	}
}
class BigTrouser extends Finery{
	public void Show() {
		System.out.println("垮裤"); super.Show();
	}
}
class Sneakers extends Finery{
	public void Show() {
		System.out.println("破球鞋"); super.Show();
	}
}
class Suit extends Finery{
	public void Show() {
		System.out.println("西装"); super.Show();
	}
}
class Tie extends Finery{
	public void Show() {
		System.out.println("领带"); super.Show();
	}
}
class LeatherShoes extends Finery{
	public void Show() {
		System.out.println("皮鞋"); super.Show();
	}
}
public  class Main{
	public static void main(String[] args){
		Person xc=new Person("小菜");
		System.out.println("\n第一种装扮");
		Sneakers p=new Sneakers();
		BigTrouser k=new BigTrouser();
		TShirts d=new TShirts();
	    p.Decorate(xc);
		k.Decorate(p);
		d.Decorate(k);
		d.Show();
		System.out.println("\n第二种装扮");
		LeatherShoes px=new LeatherShoes();
		Tie l=new Tie();
		Suit x=new Suit();
		px.Decorate(xc);
		l.Decorate(px);
		x.Decorate(l);
		x.Show();
	}
}