这是一篇关于java中双重检查加锁的翻译,原文见The "Double-Checked Locking is Broken" Declaration,这篇文章讲述了java双重检查加锁的失效原因以及解决办法,从宣言的签名来看,是非常权威的文章。 我会一段一段地给出原文,然后在下面给出翻译,翻译这篇文章,旨在学习交流,并不保留任何权利,也不承担任何责任。
publicclassSingleton{privatestaticSingleton instance =null;privateSingleton(){}publicstaticSingletongetInstance(){if(instance ==null) { instance =newSingleton(); }returninstance; } } 上面是最原始的模式,一眼就可以看出,在多线程环境下,可能会产生多个Singleton实例,于是有了其同步的版本: publicclassSingleton...
这种策略称为双重锁模式。 Double-checked locking is broken# 但是helper = new Helper()不是原子操作,它由分配空间、初始化对象字段和分配地址的多条指令组成helper。 为了显示那里真正发生了什么,我们helper = new Helper()用一些伪代码进行扩展。 为了提高整体性能,一些编译器、内存系统或处理器可能会重新排序指令...
1 C++ and the Perils of Double-Checked Locking : Workaround? 2 Proper compiler intrinsics for double-checked locking? 1 double checked locking pattern in c++ concurrent programming 6 Is my Double-Checked Locking Pattern implementation right? 2 Acquire barrier in the double checked locking pattern ...
Double-Checked Locking方法被广泛的使用于实现多线程环境下单例模式的懒加载方式实现,不幸的是,在JAVA中,这种方式有可能不能够正常工作。在其他语言环境中,如C++,依赖于处理器的内存模型、编译器的重排序以及编译器和同步库之间的工作方式。由于这些问题在C++中并不确定,因此我们不能够确定具体的行为。但是在C++中显示...
There are lots of reasons it doesn't work. The first couple ofreasons we'll describe are more obvious. After understanding those, you may be temptedto try to devise a way to "fix" the double-checked locking idiom. Your fixes will notwork: there are more subtle reasons why your fix won...
双重检查锁(double checked locking)是对上述问题的一种优化。先判断对象是否已经被初始化,再决定要不要加锁。 错误的双重检查锁 public class Singleton { private static Singleton uniqueSingleton; private Singleton() { } public Singleton getInstance() { ...
Double-Checked Lock [翻译]双重检查加锁损坏宣言(The "Double-Checked Locking is Broken" Declaration) https://www.jianshu.com/p/e3652c4a236d Java中的双重检查锁(double checked locking) https://www.cnblogs.com/xz816111/p/8470048.html
This is the reason why double checked locking is broken. Synchronize guarantees, that only one thread can enter a block of code. But it doesn't guarantee, that variables modifications done within synchronized section will be visible to other threads. Only the threads that enters the synchronized...
这样虽然解决了问题,但是因为用到了synchronized,会导致很大的性能开销,并且加锁其实只需要在第一次初始化的时候用到,之后的调用都没必要再进行加锁。 双重检查锁 双重检查锁(double checked locking)是对上述问题的一种优化。先判断对象是否已经被初始化,再决定要不要加锁。