标签：常量 span tom exe run vat 左移 final nal
1.变量
ThreadPoolExecutor先定义了这几个常量，初看时一脸懵逼，其实它就是用int的二进制高三位来表示线程池的状态，
先回顾一下位运算：
private final AtomicInteger ctl = new AtomicInteger(ctlOf(RUNNING, 0));
private static final int COUNT_BITS = Integer.SIZE - 3;// 29
private static final int CAPACITY = (1 << COUNT_BITS) - 1; // 1<<29=00100000 00000000 00000000 00000000 再减1=00011111 11111111 11111111 11111111
// 1的二进制是001，取反是110，再加1是111,111就是-1的二进制，再左移29，
private static final int RUNNING = -1 << COUNT_BITS;// 11100000 00000000 00000000 00000000
private static final int SHUTDOWN = 0 << COUNT_BITS;// 00000000 00000000 00000000 00000000
private static final int STOP = 1 << COUNT_BITS;// 00100000 00000000 00000000 00000000
private static final int TIDYING = 2 << COUNT_BITS;// 01000000 00000000 00000000 00000000
private static final int TERMINATED = 3 << COUNT_BITS;// 01100000 00000000 00000000 00000000
标签：常量 span tom exe run vat 左移 final nal
原文地址：https://www.cnblogs.com/akaneblog/p/11462549.html
