23种设计模式之装饰器模式

装饰器模式：动态地给一个对象添加一些额外的职责，就增加功能来说，装饰器模式比生成子类更加灵活。

 

package designMode.decorator;

abstract class Component {
    public abstract void operation(); 
}

package designMode.decorator;

class ConcreteComponent extends Component{

    @Override
    public void operation() {
        System.out.println("具体对象的操作！");
    }

}

package designMode.decorator;

class ConcreteDecoratorA 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);
    }
}

class ConcreteDecoratorB extends Decorator{
    
    @Override
    public void operation() {
        super.operation();
        addedBehavior();
        System.out.println("具体装饰对象B的操作！");
    }
    private void addedBehavior(){
        
    }
}

package designMode.decorator;

abstract class Decorator extends Component{
    protected Component component;

    public void setComponent(Component component) {
        this.component = component;
    }
    
    @Override
    public void operation() {
        if(component!=null)
            component.operation();
    }
}

package designMode.decorator;

public class Test {
    public static void main(String[] args) {
        ConcreteComponent cc = new ConcreteComponent();
        ConcreteDecoratorA a = new ConcreteDecoratorA();
        ConcreteDecoratorB b = new ConcreteDecoratorB();
        a.setComponent(cc);
        b.setComponent(a);
        b.operation();
    }
}