【Java设计模式】之装饰模式

1.定义

装饰模式（Decorator），动态地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。

2.结构图

3.代码

Component

public interface Component {
	public void operation();	
}

Decorator

public abstract class Decorator implements Component {
	private Component component;
	public Decorator(Component component) {
		this.component = component;
	}
	@Override
	public void operation() {
		component.operation();
	}
}

ConcreteComponent

public class ConcreteComponent implements Component {
	@Override
	public void operation() {
		System.out.println("墙");
	}
}

ConcreteDecoratorA

public class ConcreteDecoratorA extends Decorator {
	public ConcreteDecoratorA(Component component) {
		super(component);
	}
	@Override
	public void operation() {
		System.out.println("刷白墙");
		super.operation();
	}
}

ConcreteDecoratorB

public class ConcreteDecoratorB extends Decorator {
	public ConcreteDecoratorB(Component component) {
		super(component);
	}
	@Override
	public void operation() {
		System.out.println("贴墙纸");
		super.operation();
	}
}

Test

public class Test {
	public static void main(String[] args) {
		Component component = new ConcreteComponent();
		Decorator decorator = new ConcreteDecoratorB(new ConcreteDecoratorA(component));
		decorator.operation();
	}
}

4.实际应用中的例子：java io