Java开发网 - 单子模式的双重检测

Topic: 单子模式的双重检测

1.单子模式的双重检测

Posted by: andy_wang_5
Posted on: 2007-09-25 11:28

public class LazySingleton {
public static LazySingleton m_instance = null;
/**
*私有的默认构造函数,保证外界没办法直接实列化。
*/
private LazySingleton() {}
/**
*静态工厂方法，返回此类的惟一实列
*/
public static LazySingleton getInstance() {
if (m_instance == null) {
//more than one threads might be here!!!
synchronized (LazySingleton.class) {
if (m_instance == null) {
m_instance = new LazySingleton();
}
}
}
return m_instance;
}
}

为什么如上的双重检测不适用于java,而使用与C++ ?请高手指点。

2.Re:单子模式的双重检测 [Re: andy_wang_5]	Copy to clipboard
Posted by: JiafanZhou Posted on: 2007-09-25 17:11 C++ uses a different thread scheduling mechanism which is different from the one in Java in essence.