源码：java.util.concurrent.locks.ReentrantLock.Sync 源码解析

1. TODO

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2. 脑图

1. Xmind

2. Edraw

3. Hexo 地址
   👉 http://blog.wangjia.ink/2025/09/02/源码：java.util.concurrent.locks.ReentrantLock.Sync源码解析/

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3. 基础部分

3.1. ReentrantLock.Sync 概述

Sync 是一个抽象类，是 java.util.concurrent.locks.ReentrantLock 的静态内部类，继承了 java.util.concurrent.locks.AbstractQueuedSynchronizer

[!NOTE] 注意事项

1. 详见源码：ReentrantLock
   1. obsidian 内部链接：
      1. 源码：java.util.concurrent.locks.ReentrantLock源码解析
   2. Hexo 链接：
      1. http://blog.wangjia.ink/2025/08/31/源码：java.util.concurrent.locks.ReentrantLock源码解析/
2. 详见源码：AbstractQueuedSynchronizer
   1. obsidian 内部链接：
      1. 源码：java.util.concurrent.locks.AbstractQueuedSynchronizer源码解析
   2. Hexo 链接：
      1. http://blog.wangjia.ink/2025/09/01/源码：java.util.concurrent.locks.AbstractQueuedSynchronizer源码解析/

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4. 源码部分

abstract static class Sync extends AbstractQueuedSynchronizer {
	
	@ReservedStackAccess
	final boolean tryLock() {
		Thread current = Thread.currentThread();
		int c = getState();
		if (c == 0) {
			if (compareAndSetState(0, 1)) {
				setExclusiveOwnerThread(current);
				return true;
			}
		} else if (getExclusiveOwnerThread() == current) {
			if (++c < 0)
				throw new Error("Maximum lock count exceeded");
			setState(c);
			return true;
		}
		return false;
	}
	
	abstract boolean initialTryLock();
	
	@ReservedStackAccess
	final void lock() {
		if (!initialTryLock())
			acquire(1);
	}
	
	@ReservedStackAccess
	final void lockInterruptibly() throws InterruptedException {
		if (Thread.interrupted())
			throw new InterruptedException();
		if (!initialTryLock())
			acquireInterruptibly(1);
	}
	
	@ReservedStackAccess
	final boolean tryLockNanos(long nanos) throws InterruptedException {
		if (Thread.interrupted())
			throw new InterruptedException();
		return initialTryLock() || tryAcquireNanos(1, nanos);
	}
	
	@ReservedStackAccess
	protected final boolean tryRelease(int releases) {
		int c = getState() - releases;
		if (getExclusiveOwnerThread() != Thread.currentThread())
			throw new IllegalMonitorStateException();
		boolean free = (c == 0);
		if (free)
			setExclusiveOwnerThread(null);
		setState(c);
		return free;
	}
	
	protected final boolean isHeldExclusively() {
		return getExclusiveOwnerThread() == Thread.currentThread();
	}
	
	final ConditionObject newCondition() {
		return new ConditionObject();
	}
	
	final Thread getOwner() {
		return getState() == 0 ? null : getExclusiveOwnerThread();
	}
	
	final int getHoldCount() {
		return isHeldExclusively() ? getState() : 0;
	}
	
	final boolean isLocked() {
		return getState() != 0;
	}
	
	private void readObject(java.io.ObjectInputStream s)
		throws java.io.IOException, ClassNotFoundException {
		s.defaultReadObject();
		setState(0);
	}
	
}

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