装饰者模式

应用场景

装饰者类是对功能的增强，装饰者增强的是跟原始类相关的功能

类结构

public abstract class Component {
    public abstract void operate();
}

public class ConcreteComponent extends Component{
    @Override
    public void operate() {
        System.out.println("ConcreteComponent operate");
    }
}

public abstract class Decorator extends Component{

    private Component component;

    public Decorator(Component component) {
        this.component = component;
    }

    @Override
    public void operate() {
        this.component.operate();
    }
}

public class ConcreteDecoratorA extends Decorator{
    public ConcreteDecoratorA(Component component) {
        super(component);
    }

    @Override
    public void operate() {
        super.operate();
        System.out.println("ConcreteDecoratorA operate");
    }
}