Decorator
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Brief introduction about Decorator.
装饰模式（Decorator）
动态地给一个对象添加一些额外的职责，就增加功能来说，装饰模式比生成子类更为灵活。
场景
假设有个4S店，卖车。卖的🚗有宝马BMW和特斯拉的ModelX。 车分基本款和在此基础上的定制款。客户可以定制自己的爱车🚗，例如定制真皮座椅💺，和定制音响设备。
赵四买了个ModelX，改装了音响系统。
刘能看赵四买了ModelX，他想我也得整一个呀！ 他买了的BMW，要装真皮座椅，和更牛的音响系统，让全村人都知道他刘能🐂🍺。
以上就是装饰模式的意思。
装饰模式
代码
Client
public class Client {
public static void main(String[] args) {
ICar bmw = new BMW();
bmw.makeOrder();
// A new order has been made.Car: u006.BMW
// decorate
ICar bmw_leather = new LeatherSeats(bmw);
ICar bmw_addAudio = new AudioDecorator(bmw_leather);
bmw_addAudio.makeOrder();
// A new order has been made.Car: u006.BMW
// Leather seats have been added.
// Audio devices are awesome.
ICar modelX = new ModelX();
modelX.makeOrder();
// A new order has been made. Car: u006.ModelX
// decorate
ICar modelX_audio = new AudioDecorator(modelX);
modelX_audio.makeOrder();
// A new order has been made. Car: u006.ModelX
// Audio devices are awesome.
}
}
package u006;
/**
* Created by HuGuodong on 11/20/19.
*/
public interface ICar {
void makeOrder();
}
class ModelX implements ICar {
@Override
public void makeOrder() {
System.out.println("A new order has been made. Car: " + this.getClass().getName());
}
}
class BMW implements ICar {
@Override
public void makeOrder() {
System.out.println("A new order has been made.Car: " + this.getClass().getName());
}
}
abstract class CarDecorator implements ICar{
protected ICar car;
public CarDecorator(ICar car) {
this.car = car;
}
public abstract void makeOrder();
}
class AudioDecorator extends CarDecorator {
public AudioDecorator(ICar car) {
super(car);
}
@Override
public void makeOrder() {
car.makeOrder();
showAudioDevices();
}
public void showAudioDevices(){
System.out.println("Audio devices are awesome.");
}
}
class LeatherSeats extends CarDecorator {
public LeatherSeats(ICar car) {
super(car);
}
@Override
public void makeOrder() {
car.makeOrder();
addLeatherSeats();
}
private void addLeatherSeats(){
System.out.println("Leather seats have been added.");
}
}
2019-11-19
