设计模式 - 结构型模式 - 装饰模式

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//抽象界面构件类：抽象构件类，为了突出与模式相关的核心代码，对原有控件代码进行了大量的简化
abstract class Component {
    public abstract void display();
}

//窗体类：具体构件类
class Window extends Component {
    public void display() {
        System.out.println("显示窗体！");
    }
}

//文本框类：具体构件类
class TextBox extends Component {
    public void display() {
        System.out.println("显示文本框！");
    }
}

//列表框类：具体构件类
class ListBox extends Component {
    public void display() {
        System.out.println("显示列表框！");
    }
}

//构件装饰类：抽象装饰类
class ComponentDecorator extends Component {
    private Component component; //维持对抽象构件类型对象的引用

    public ComponentDecorator(Component component) //注入抽象构件类型的对象
    {
        this.component = component;
    }

    public void display() {
        component.display();
    }
}

//滚动条装饰类：具体装饰类
class ScrollBarDecorator extends ComponentDecorator {
    public ScrollBarDecorator(Component component) {
        super(component);
    }

    public void display()

    {
        this.setScrollBar();
        super.display();
    }

    public void setScrollBar() {
        System.out.println("为构件增加滚动条！");
    }
}

//黑色边框装饰类：具体装饰类
class BlackBorderDecorator extends ComponentDecorator {
    public BlackBorderDecorator(Component component) {
        super(component);
    }

    public void display() {
        this.setBlackBorder();
        super.display();
    }

    public void setBlackBorder() {
        System.out.println("为构件增加黑色边框！");
    }
}

class Client {
    public static void main(String args[]) {
        Component component, componentSB; //使用抽象构件定义
        component = new Window(); //定义具体构件
        componentSB = new ScrollBarDecorator(component); //定义装饰后的构件
        componentSB.display();
    }
}