2013년 10월 21일 월요일

자바 싱글톤, 쓰레드 예제

자바 싱글톤, 쓰레드 예제

public class Singleton {
    private static Singleton singleton = new Singleton();
    private Singleton() {
        System.out.println("Sington Class의 인스턴스 생성!");                   
    }
    public static Singleton getInstance() {       
        return singleton;
    }                                        
}
 
public class Main extends Thread {
    public static void main(String[] args) {
        System.out.println("Start.");       
        Singleton obj1 = Singleton.getInstance();
  Singleton obj2 = Singleton.getInstance();
        if (obj1 == obj2){
   System.out.println("obj1 == obj2");
        }
  else {
   System.out.println("obj1 != obj2");
  }
    }
}
 
=======================================
 
 
public class Singleton {
    private static Singleton singleton = null;
    private Singleton() {
        System.out.println("인스턴스 생성...");
        slowdown();                            
    }
    public static Singleton getInstance() {
        if (singleton == null) {
            singleton = new Singleton();
        }
        return singleton;
    }
    private void slowdown() {                  
        try {                                  
            Thread.sleep(10);                
        } catch (InterruptedException e) {     
        }                                      
    }                                          
}
 
 
public class Main extends Thread {
    public static void main(String[] args) {
        System.out.println("Start.");
        new Main("A").start();
        new Main("B").start();
        new Main("C").start();
        System.out.println("End.");
    }
    public void run() {
        Singleton obj = Singleton.getInstance();
        System.out.println(getName() + ": obj = " + obj);
    }
    public Main(String name) {
        super(name);
    }
}

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