public class Main

{

public static void main(String[] args)

{

// TODO Auto-generated method stub

// Singleton Pattern - 단일(전역) 객체 생성 패턴

// https://youtu.be/5jgpu9-ywtY

SystemSpeaker speaker1 = SystemSpeaker.getInstance();

SystemSpeaker speaker2 = SystemSpeaker.getInstance();

System.out.println("Speaker1 :: " + speaker1.getVolume());

System.out.println("Speaker2 :: " + speaker2.getVolume());

// 각각의 인스턴스를 조작해도 전역적으로 반영이 되는지 확인

speaker1.setVolume(11);

System.out.println("Speaker1 :: " + speaker1.getVolume());

System.out.println("Speaker2 :: " + speaker2.getVolume());

speaker2.setVolume(22);

System.out.println("Speaker1 :: " + speaker1.getVolume());

System.out.println("Speaker2 :: " + speaker2.getVolume());

}

}