java设计模式之装饰者模式

实例代码：

// 抽象类 Girl
public abstract class Girl {
    String description = "no particular";

    public String getDescription(){
        return description;
    }
}

// 美国女孩
public class AmericanGirl extends Girl {
    public AmericanGirl() {
        description = "+AmericanGirl";
    }
}

// 国产妹子
public class ChineseGirl extends Girl {
    public ChineseGirl() {
        description = "+ChineseGirl";
    }
}

// 装饰者
public abstract class GirlDecorator extends Girl {
    public abstract String getDescription();
}

// 下面以美国女孩示例
// 给美国女孩加上金发
public class GoldenHair extends GirlDecorator {

    private Girl girl;

    public GoldenHair(Girl g) {
        girl = g;
    }

    @Override
    public String getDescription() {
        return girl.getDescription() + "+with golden hair";
    }

}

// 加上身材高大的特性
public class Tall extends GirlDecorator {

    private Girl girl;

    public Tall(Girl g) {
        girl = g;
    }

    @Override
    public String getDescription() {
        return girl.getDescription() + "+is very tall";
    }

}

// 检验一下
public class Main {

    public static void main(String[] args) {
        Girl g1 = new AmericanGirl();
        System.out.println(g1.getDescription());

        GoldenHair g2 = new GoldenHair(g1);
        System.out.println(g2.getDescription());

        Tall g3 = new Tall(g2);
        System.out.println(g3.getDescription());

        // 你也可以一步到位
        // Girl g = new Tall(new GoldenHair(new AmericanGirl())); 
    }
}