AtomicBoolean做了哪些volatile boolean不能做到的事情?


当前回答

记住成语——

READ - MODIFY- WRITE这个你不能用volatile实现

其他回答

布尔基元类型是原子的,用于写和读操作,volatile保证happens before原则。因此,如果您需要一个简单的get()和set(),那么您不需要AtomicBoolean。

另一方面,如果你需要在设置一个变量的值之前执行一些检查,例如。"如果为真,则设置为假",那么您也需要原子地执行此操作,在这种情况下使用compareAndSet和AtomicBoolean提供的其他方法,因为如果您尝试使用volatile boolean实现此逻辑,则需要一些同步来确保get和set之间的值没有更改。

两者都是相同的概念,但在原子布尔中,它将为操作提供原子性,以防cpu切换发生在两者之间。

I use volatile fields when said field is ONLY UPDATED by its owner thread and the value is only read by other threads, you can think of it as a publish/subscribe scenario where there are many observers but only one publisher. However if those observers must perform some logic based on the value of the field and then push back a new value then I go with Atomic* vars or locks or synchronized blocks, whatever suits me best. In many concurrent scenarios it boils down to get the value, compare it with another one and update if necessary, hence the compareAndSet and getAndSet methods present in the Atomic* classes.

检查java.util.concurrent.atomic包中的JavaDocs,以获得Atomic类的列表和它们如何工作的出色解释(刚刚了解到它们是无锁的,因此它们比锁或同步块更有优势)

记住成语——

READ - MODIFY- WRITE这个你不能用volatile实现

你不能将compareAndSet, getAndSet作为带有volatile boolean的原子操作(除非你同步它)。