装饰器模式

Java

透明扩展

场景

动态扩展已有对象功能

代码

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public interface Component{
    void operation();
}
public class ConcreteComponent implements Component{
    @Override
    void operation(){
        //...
    }
}
public class Decorator implements Component{
    private Component component;
    public Decorator(Component component){
        this.component = component
    }
    @Override
    public void operation(){
        //增强逻辑
        component.operation();
        //增强逻辑
    }
}

调用者

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Component component = new Decorator(new ConcreteComponent());
component.operation();

特征

  • 扩展装饰类和目标对象实现一样接口
  • 扩展类在目标基础上增强逻辑

应用

java.io.InputStream的各种包装类比如BufferedInputStream

版权声明

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本文永久链接：http://linest.github.io/2016/11/19/java-pattern-decorator/