Abstractqueuedsynchronizer source code analysis of Java concurrency series (shared mode)

Through the analysis of the previous article, we know that there are three ways to obtain locks in exclusive mode: do not respond to thread interrupt, respond to thread interrupt, and set timeout. There are also three ways to obtain locks in the shared mode, and they are basically the same. We can quickly understand other ways when we figure out one. Although there are more than 1000 lines of abstractqueuedsynchronizer source code, there are many repetitions, so readers should not be frightened at the beginning. As long as they are patient to see it, they can gradually understand it. In my personal experience, there are several key points to understand when reading the abstractqueuedsynchronizer source code. They are the difference between exclusive mode and shared mode, the waiting state of nodes, and the understanding of conditional queues. If you understand these points, it will be much easier to read the follow-up source code. Of course, these are described in detail in my article "Java concurrency series [1] - summary analysis of abstractqueuedsynchronizer source code analysis", which readers can refer to first. The analysis of sharing mode in this paper is also divided into three ways to obtain locks and one way to release locks.