J.U.C & JVM

AbstractQueuedSynchronizer

ExecutorService 接口

ReentrantLock

private final Sync sync;abstract static class Sync extends AbstractQueuedSynchronizer {        ......}static final class NonfairSync extends Sync {        ......}static final class FairSync extends Sync {        ......}public ReentrantLock(boolean fair);  初始化时确定使用公平锁还是非公平锁void lock();void unlock();boolean tryLock();public final boolean isFair()

Blocked

load

Y

按饱和策略 处理无法执行的任务

N

Runnable包括 \"运行\"和\"就绪\"

抢到锁

read

New

运行中

创建线程执行任务

ReadWriteLock 接口

Lock readLock();Lock writeLock();

notify()notifyAll()

assign

Executor 接口

void execute(Runnable command);

执行完

超出最大线程数？

Terminated

主内存

ThreadLocalMap

store

超出核心线程数？

线程池运行机制

use

Lock 锁组件

这两个状态的区别就是：Waiting 直到被其它线程唤醒才会回到Runnable状态；TimedWaiting 在等待了设置的时间后，自动进入Runnable状态

线程状态转换图

Executors 线程池工具类

public static ExecutorService newFixedThreadPool(int nThreads);public static ExecutorService newSingleThreadExecutor();public static ExecutorService newCachedThreadPool();

TimedWaiting

notify()notifyAll()等待超时

等待获取锁

Waiting

ThreadPoolExecutor

private final BlockingQueue<Runnable> workQueue;private volatile ThreadFactory threadFactory;private volatile int corePoolSize;private volatile int maximumPoolSize;public void execute(Runnable command);

1、每个Thread对象都持有一个ThreadLocalMap对象；2、当调用一个ThreadLocal的set方法时，先得到当前线程的ThreadLocalMap对象，然后将<ThreadLocal，value>键值对插入到该Map中

工作内存A

系统

调度

Thread1

抢到时间片就“运行”，抢不到就“就绪”

提交任务

就绪

Thread2

AbstractExecutorService

从上面继承等待 submit()、execute() 等方法

线程A

Lock 接口

void lock();void unlock();boolean tryLock();

write

工作队列已满？

sleep(long)wait(long)join(long)

任务添加到队列，等待执行

ReentrantReadWriteLock

private final ReentrantReadWriteLock.ReadLock readerLock;private final ReentrantReadWriteLock.WriteLock writerLock;final Sync sync;abstract static class Sync extends AbstractQueuedSynchronizer {        ......}static final class NonfairSync extends Sync {        ......}static final class FairSync extends Sync {        ......}public static class ReadLock implements Lock {        ......}public static class WriteLock implements Lock {        ......}public ReentrantReadWriteLock(boolean fair);初始化时确定：实例化非公平读写锁，还是公平读写锁public ReentrantReadWriteLock.WriteLock writeLock();public ReentrantReadWriteLock.ReadLock  readLock()public final boolean isFair();

Executor 线程池组件

wait()join()