Java 装饰模式 （Decorator）

装饰模式

package gx.component;

/**
* 组件：装饰类和被装饰类 都要继承：为了类型保持一致
* @author always
*
*/
public abstract class Component {

public abstract void description();
public abstract int cost();
}

package gx.component.impl;

import gx.component.Component;

/**
* 装饰类的抽象类
* @author always
*
*/
public abstract class  Decorator extends Component{

protected Component component;
}

package gx.component.impl;

import gx.component.Component;

/**
*
* 被包装的类
* @author always
*
*/
public class Phone extends Component{

public void description() {
System.out.println("裸机");
}

public int cost() {

return 1900;
}

}

package gx.decorator.impl;

import gx.component.Component;
import gx.component.impl.Decorator;

/**
*
* 装饰1：给手机买个壳
* @author always
*
*/
public class DaiKe extends Decorator{

public DaiKe(){

}

public DaiKe(Component component){
this.component=component;
}
public void description() {
this.component.description();
System.out.println("带了手机壳");
}

public int cost() {
return 50+this.component.cost();
}

}

package gx.decorator.impl;

import gx.component.Component;
import gx.component.impl.Decorator;

/**
*
* 装饰2：给手机贴个膜
* @author always
*
*/
public class TieMo extends Decorator{

public TieMo(){}

public TieMo(Component component){
this.component=component;
}

public void description() {
this.component.description();
System.out.println("贴了膜");
}

public int cost() {
return 20+this.component.cost();
}

}

package gx;

import gx.component.Component;
import gx.component.impl.Phone;
import gx.decorator.impl.DaiKe;
import gx.decorator.impl.TieMo;
import junit.framework.TestCase;

public class TestDecorator extends TestCase {

public void testDecorator() {

Component component = new TieMo(new DaiKe(new Phone()));

component.description();
System.out.println("价钱：" + component.cost());
/*
* 结果：
*  裸机
*  带了手机壳
*  贴了膜
*  价钱：1970
*/
}
}