装饰者模式后续理解消化中

/**

 * 

 */

package decorator2;



/**

 * @author wangjian2

 *

 */

public interface InterfaceComponent {

    public void say();

}

package decorator2;



public class Component implements InterfaceComponent {



    @Override

    public void say() {

        System.out.println("Component.say():原组件的方法！");

    }



}

package decorator2;



public abstract class AbstractDecorator implements InterfaceComponent {



    private InterfaceComponent component;



    public AbstractDecorator(InterfaceComponent component) {

        this.component = component;

    }



    /**

     * 组件方法执行前预处理方法

     * 

     */

    protected void preSay() {

    };



    /**

     * 组件方法执行后处理方法

     * 

     */

    protected void afterSay() {

    };



    public void say() {



        preSay();

        component.say();

        afterSay();



    };

}

package decorator2;



public class DecoratorTwo extends AbstractDecorator {



    public DecoratorTwo(InterfaceComponent component) {

        super(component);

        // TODO 自动生成构造函数存根

    }



    /**

     * 根据需要重载模板类preSay()方法

     */

    protected void preSay() {

        System.out.println("DecoratorTwo.preSay():装饰者二的preSay()方法！");

    }



    /**

     * 根据需要重载模板类afterSay()方法

     */

    protected void afterSay() {

        System.out.println("DecoratorTwo.afterSay():装饰者二的afterSay()方法！");

    }



}

package decorator2;



public class DecoratorOne extends AbstractDecorator {



    public DecoratorOne(InterfaceComponent component) {

        super(component);

        // TODO 自动生成构造函数存根

    }



    /**

     * 根据需要重载模板类preSay()方法

     */

    protected void preSay() {

        System.out.println("DecoratorOne.preSay():装饰者一的preSay()方法！");

    }



    /**

     * 根据需要重载模板类afterSay()方法

     */

    protected void afterSay() {

        System.out.println("DecoratorOne.afterSay():装饰者一的afterSay()方法！");

    }



    /**

     * 测试方法

     * 

     * @param args

     */

    public static void main(String[] args) {

        // TODO 自动生成方法存根

        InterfaceComponent interfaceComponent = new DecoratorTwo(

                new DecoratorOne(new Component()));

        interfaceComponent.say();

        /*

         * 控制台输出： DecoratorTwo.preSay():装饰者二的preSay()方法！

         * DecoratorOne.preSay():装饰者一的preSay()方法！ Component.say():原组件的方法！

         * DecoratorOne.afterSay():装饰者一的afterSay()方法！

         * DecoratorTwo.afterSay():装饰者二的afterSay()方法！

         */

    }

}

 

执行顺序：

interfaceComponent.say()=》DecoratorTwo继承AbstractDecorator的say()方法，并执行该方法=》执行DecoratorTwo的preSay方法=》
DecoratorTwo的构造方法的参数component是DecoratorOne，所以执行DecoratorOne的say方法=》
执行DecoratorOne的preSay方法=》执行Component类的say()方法=》执行DecoratorOne的afterSay方法=》
执行DecoratorTwo的afterSay方法
输出结果：

DecoratorTwo.preSay():装饰者二的preSay()方法！
DecoratorOne.preSay():装饰者一的preSay()方法！
Component.say():原组件的方法！
DecoratorOne.afterSay():装饰者一的afterSay()方法！
DecoratorTwo.afterSay():装饰者二的afterSay()方法！

二、另一种装饰者模式代码

/**

 * 

 */

package decorator3;



/**

 * @author wangjian2

 *

 */

public interface Component {

    

    public double price();

}

/**

 * 

 */

package decorator3;



/**

 * @author wangjian2

 *

 */

public class AllNeedMilk implements Component {

    private double price = 10.5;



    @Override

    public double price() {

        // TODO Auto-generated method stub

        return this.price;

    }



}

/**

 * 

 */

package decorator3;



/**

 * @author wangjian2

 *

 */

public abstract class Fruit implements Component {

    private Component component;

    

    public Fruit(Component component) {

        this.component = component;

    }

    

    protected double newPrice() {

        return 0;

    }

    

    public double price(){

        return newPrice()+component.price();

    }

}

/**

 * 

 */

package decorator3;



/**

 * @author wangjian2

 *

 */

public class Apple extends Fruit {



    public Apple(Component component) {

        super(component);

        // TODO Auto-generated constructor stub

    }

    

    protected double newPrice() {

        return 20;

    }



}

/**

 * 

 */

package decorator3;



/**

 * @author wangjian2

 *

 */

public class Orange extends Fruit {



    public Orange(Component component) {

        super(component);

        // TODO Auto-generated constructor stub

    }

    

    protected double newPrice() {

        return 30;

    }



}

/**

 * 

 */

package decorator3;



/**

 * @author wangjian2

 *

 */

public class Test {



    /**

     * @param args

     */

    public static void main(String[] args) {

        Component apple = new Apple(new Orange(new AllNeedMilk()));

        System.out.println(apple.price());

        Component orange = new Orange(new AllNeedMilk());

        System.out.println(orange.price());

    }



}

输出结果：

60.5
40.5