装饰模式：动态的给一个对象添加一些额外的职责，就增加功能来说，装饰模式比生成子类更为灵活。
UML图：
模型类：
Component类：
package com.cnblog.clarck; /**
* 接口对象，可以动态的给对象添加职责
*
* @author clarck
*
*/
public abstract class Component {
public abstract void Operation();
}
ConcreateComponent类：
package com.cnblog.clarck; /**
* 具体的装饰对象，起到给Component添加职责
*
* @author clarck
*
*/
public class ConcreateComponent extends Component { @Override
public void Operation() {
System.out.println("具体对象的操作");
} }
Decorator类：
package com.cnblog.clarck; /**
* 装饰抽象类，继承了Component,从外来类来扩展Component类的功能，
* 但对于Component来说是不需要知道Decorator的存在的。
*
* @author clarck
*
*/
public abstract class Decorator extends Component {
protected Component mComponent; public void setComponent(Component component) {
mComponent = component;
} @Override
public void Operation() {
if (mComponent != null) {
mComponent.Operation();
}
} }
ConcreateDecoratorA类：
package com.cnblog.clarck; /**
* 具体的的装饰对象，起到给Component添加职责的作用
*
* @author clarck
*
*/
public class ConcreateDecoratorA extends Decorator {
private String addedState; @Override
public void Operation() {
super.Operation();
addedState = "New State";
System.out.println("具体装饰对象A的操作" + addedState);
} }
ConcreateDecoratorB类：
package com.cnblog.clarck; /**
* 具体的装饰类B
*
* @author clarck
*
*/
public class ConcreateDecoratorB extends Decorator { @Override
public void Operation() {
super.Operation();
addedBehaivor();
System.out.println("具体装饰对象B");
} private void addedBehaivor() { //用来区别ConcreateDecoratorA }
}
测试类:
package com.cnblog.clarck; /**
* 测试类
*
* @author clarck
*
*/
public class Test {
public static void main(String[] args) {
ConcreateComponent component = new ConcreateComponent();
ConcreateDecoratorA decoratorA = new ConcreateDecoratorA();
ConcreateDecoratorB decoratorB = new ConcreateDecoratorB(); decoratorA.setComponent(component);
decoratorB.setComponent(decoratorA);
decoratorB.Operation();
}
}