java - 做 “nothing”而 “condition”

浏览ForkJoinPool的Java 8版本(与Java 7相比有一些有趣的变化)的代码时，我遇到了这个结构(here):

do {} while (!blocker.isReleasable() &&
             !blocker.block());

我在为您为什么要像这样写而苦苦挣扎

while (!blocker.isReleasable() &&
       !blocker.block());

因为您可以将第一个构造读取为do "nothing" while "conditions"，这仅仅是语义/可读性的选择吗？还是我还缺少其他好处？

最佳答案

如果您在类声明下面的文件顶部阅读注释，则有一节说明了此构造的用法:

Style notes

===========

[...]

There are several occurrences of the unusual "do {} while
(!cas...)"  which is the simplest way to force an update of a
CAS'ed variable. There are also other coding oddities (including
several unnecessary-looking hoisted null checks) that help
some methods perform reasonably even when interpreted (not
compiled).

Blocker

java - 做 “nothing”而 “condition”