package com.natian.pattern;
/**
* @author：bryant
* @date：Mar 9, 2014 12:37:13 PM
*
* 对于单例模式在多线程下的double check
* reference: http://zh.wikipedia.org/wiki/%E5%8F%8C%E9%87%8D%E6%A3%80%E6%9F%A5%E9%94%81%E5%AE%9A%E6%A8%A1%E5%BC%8F
http://stackoverflow.com/questions/18093735/double-checked-locking-in-singleton
*/
public class TestSingleton {
private static TestSingleton instance;
private TestSingleton() {}
/**
* 效率最高
* @return
*/
public static TestSingleton getInsatance() {
if(instance == null){
//TestSingleton.class锁住的是字节码文件
synchronized (TestSingleton.class) {
if(instance == null){
instance = new TestSingleton();
}
}
}
return instance;
}
/**
* 效率其次
* @return
*/
public static synchronized TestSingleton getInsatance2() {
if(instance == null){
instance = new TestSingleton();
}
return instance;
}
public static void main(String[] args) {
// TODO Auto-generated method stub
}
}