大话设计模式-装饰模式

/**
 * 被装饰的对象接口 可以给继承自此类的子对象动态的添加职责
 */
public abstract class Component {
    public abstract void Operation();
}

/**
 * 具体的对象 可以给其动态的添加职责
 */
public class ConcreteComponent extends Component {
    @Override
    public void Operation() {
        System.out.println("具体对象的操作");
    }
}

/**
 * 具有装饰功能的类 可以给Component的子类动态的添加职责
 */
public class Decorator extends Component {
    protected Component component;

    public Decorator() {
    }

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

    public void setComponent(Component component) {
        this.component = component;
    }

    @Override
    public void Operation() {
        if (component != null) {
            component.Operation();
        }
    }
}

/**
 * 具体的装饰类 给Component的子类添加A职责
 */
public class ConcreteDecoratorA extends Decorator {
    public ConcreteDecoratorA() {
        super();
    }

    public ConcreteDecoratorA(Component component) {
        super(component);
    }

    @Override
    public void Operation() {
        super.Operation();
        System.out.print("具体装饰对象A的操作->");
        initA();
    }

    private void initA() {
        System.out.println("A类独有的方法，区别于B类");
    }
}

/**
 * 具体的装饰类 给Component的子类添加B职责
 */
public class ConcreteDecoratorB extends Decorator {
    public ConcreteDecoratorB() {
    }

    public ConcreteDecoratorB(Component component) {
        super(component);
    }

    @Override
    public void Operation() {
        super.Operation();
        System.out.print("具体装饰对象B的操作->");
        initB();
    }

    private void initB() {
        System.out.println("B类独有的方法，区别于A类");
    }
}

public class Main {
    public static void main(String[] args) {
        //第一种创建方法
        //concreteComponent 是被装饰的对象 下面将为其添加AB职责
        ConcreteComponent concreteComponent = new ConcreteComponent();
        ConcreteDecoratorA concreteDecoratorA = new ConcreteDecoratorA();
        ConcreteDecoratorB concreteDecoratorB = new ConcreteDecoratorB();

        concreteDecoratorA.setComponent(concreteComponent);
        concreteDecoratorB.setComponent(concreteDecoratorA);
        concreteDecoratorB.Operation();

        //第二种创建方法
        ConcreteDecoratorB b =
                new ConcreteDecoratorB(
                        new ConcreteDecoratorA(
                                new ConcreteComponent()));
        b.Operation();
    }
}