一、前言：
外观模式的注意事项与细节：
- 外观模式对外屏蔽了子系统的细节，从而降低了客户端与子系统的复杂性。
- 外观模式降低了客户端与子系统的耦合性，让子系统内部易于维护与扩展。
- 通过合理的使用外观模式，可以帮助我们更好的划分访问的层次。
二、UML图：
三、组合模式：
3.1、代码实例：
Step 1) 创建 DVDPlayer 类：
public class DVDPlayer {
private static DVDPlayer instance = new DVDPlayer();
public static DVDPlayer getInstanc(){
return instance;
}
public void on(){
System.out.println(" DVD Open !");
}
public void off(){
System.out.println(" DVD Off !");
}
public void play(){
System.out.println(" DVD is playing !");
}
public void pause(){
System.out.println(" DVD is pause !");
}
}
Step 2) 创建 Popcorn 实现类：
public class Popcorn {
private static Popcorn instance = new Popcorn();
public static Popcorn getInstanc(){
return instance;
}
public void on(){
System.out.println(" Popcorn Open !");
}
public void off(){
System.out.println(" Popcorn Off !");
}
public void pop(){
System.out.println(" Popcorn is pop !");
}
public void pause(){
System.out.println(" Popcorn is pause !");
}
}
Step 3) 创建 Projector 实现类：
public class Projector {
private static Projector instance = new Projector();
public static Projector getInstanc(){
return instance;
}
public void on(){
System.out.println(" Projector Open !");
}
public void off(){
System.out.println(" Projector Off !");
}
public void focus(){
System.out.println(" Projector is focus !");
}
}
Step 4) 创建 Screen 实现类：
public class Screen {
private static Screen instance = new Screen();
public static Screen getInstanc(){
return instance;
}
public void up(){
System.out.println(" Screen up !");
}
public void down(){
System.out.println(" Screen down !");
}
}
Step 5) 创建 Stereo 实现类：
public class Stereo {
private static Stereo instance = new Stereo();
public static Stereo getInstanc(){
return instance;
}
public void on(){
System.out.println(" Stereo Open !");
}
public void off(){
System.out.println(" Stereo Off !");
}
public void up(){
System.out.println(" Stereo is up !");
}
}
Step 6) 创建 TheaterLight 实现类：
public class TheaterLight {
private static TheaterLight instance = new TheaterLight();
public static TheaterLight getInstanc(){
return instance;
}
public void on(){
System.out.println(" TheaterLight Open !");
}
public void off(){
System.out.println(" TheaterLight Off !");
}
public void dim(){
System.out.println(" TheaterLight is dim !");
}
public void bright(){
System.out.println(" TheaterLight is bright !");
}
}
Step 7) 创建 HomeTheaterFacade 实现类：
public class HomeTheaterFacade {
private TheaterLight theaterLight;
private Popcorn popcorn;
private Stereo stereo;
private Projector projector;
private Screen screen;
private DVDPlayer dvdPlayer;
public HomeTheaterFacade() {
this.theaterLight = TheaterLight.getInstanc();
this.popcorn = Popcorn.getInstanc();
this.stereo = Stereo.getInstanc();
this.projector = Projector.getInstanc();
this.screen = Screen.getInstanc();
this.dvdPlayer = DVDPlayer.getInstanc();
}
public void ready(){
popcorn.on();
popcorn.pop();
screen.down();
projector.on();
stereo.on();
dvdPlayer.on();
theaterLight.dim();
}
public void play(){
dvdPlayer.play();
}
public void pause(){
dvdPlayer.pause();
}
public void end(){
popcorn.off();
theaterLight.bright();
screen.up();
projector.off();
stereo.off();
dvdPlayer.off();
}
}
Step 8) 创建 main 方法：
public class Client {
public static void main(String[] args) {
HomeTheaterFacade homeTheaterFacade = new HomeTheaterFacade();
homeTheaterFacade.ready();
System.out.println("------------------");
homeTheaterFacade.play();
System.out.println("------------------");
homeTheaterFacade.end();
System.out.println("------------------");
}
}
• 由 ChiKong_Tam 写于 2020 年 10 月 18 日