1、定义一个接口Component
public interface Component { void operation();
}
2、创建一个实现了Component接口的简单类SimpleComponent
public class SimpleComponent implements Component { @Override public void operation() { System.out.println("SimpleComponent operation."); }
}
3、创建一个装饰器基类Decorator，它也实现了Component接口，并持有一个对Component对象的引用
public abstract class Decorator implements Component { protected Component component; public Decorator(Component component) { this.component = component; } @Override public void operation() { if (component != null) { component.operation(); } }
}
4、创建一个具体的装饰器类，例如ConcreteDecoratorA，它添加了一些额外的功能
public class ConcreteDecoratorA extends Decorator { public ConcreteDecoratorA(Component component) { super(component); } @Override public void operation() { super.operation(); addedFunctionA(); } private void addedFunctionA() { System.out.println("ConcreteDecoratorA added function."); }
}
5、编写一个测试类来展示如何使用装饰器
public class DecoratorPatternDemo { public static void main(String[] args) { Component simpleComponent = new SimpleComponent(); Component decoratedComponent = new ConcreteDecoratorA(simpleComponent); decoratedComponent.operation(); }
}
