装饰器模式的定义: 动态的给一个对象添加额外的职责,就功能来说,装饰模式相比子类更为灵活
装饰器模式的四个角色:
抽象构件角色
public interface Componment {
public void doingProcedureA();
}
具体构件角色
public class ConcreteComponmentA implements Componment {
@Override
public void doingProcedureA() {
System.out.println("Componment A is doing ProcedureA");
}
}
装饰角色
public abstract class Decorator implements Componment {
protected Componment component;
public Decorator(Componment componment) {
this.component = componment;
}
@Override
public void doingProcedureA() {
component.doingProcedureA();
}
}
具体装饰角色
在具体装饰角色中,我们需要加入装饰方法,并将装饰方法在构建的方法中进行调用
public class ConcreateDecorator extends Decorator {
public ConcreateDecorator(Componment componment) {
super(componment);
}
public void extraFunction() {
System.out.println("Doing Extara Function");
}
public void doingProcedureA() {
this.extraFunction();
super.doingProcedureA();
}
}
调用展示
public class Client {
public static void main(String[] args) {
Componment componment = new ConcreteComponmentA();
componment = new ConcreateDecorator(componment);
componment = new ConcreateDecorator(componment);
componment.doingProcedureA();
}
}
装饰器模式的优点:
装饰器模式的应用场景:
装饰器模式的缺点: