public final void acquire(int arg) {if (!tryAcquire(arg) &&acquireQueued(addWaiter(Node.EXCLUSIVE), arg))selfInterrupt();
}

public final boolean release(int arg) {if (tryRelease(arg)) {Node h = head;if (h != null && h.waitStatus != 0)unparkSuccessor(h);return true;}return false;
}

ReentrantLock的并发控制是通过继承AbstractQueuedSynchronizer()来实现并发的。abstract static class Sync extends AbstractQueuedSynchronizer{...
}

protected final boolean tryAcquire(int acquires) {return nonfairTryAcquire(acquires);
}final boolean nonfairTryAcquire(int acquires) {final Thread current = Thread.currentThread();int c = getState();// 0 表示当前没有其他线程占用if (c == 0) {//通过cas的方式来设置state,如果设置成功，则认为当前线程可以获取锁，cas失败则任务其他线程比他快一步占用if (compareAndSetState(0, acquires)) {//设置当前线程独占setExclusiveOwnerThread(current);//返回true,即不需要放入等待的链表中return true;}}//如果当前线程本来就占有锁else if (current == getExclusiveOwnerThread()) {//占用的次数+1,这也是为什么 lock()和unlock()需要一一对应int nextc = c + acquires;//说明同一个线程lock()的次数为int的最大值if (nextc < 0) // overflowthrow new Error("Maximum lock count exceeded");// 设置state,返回获取锁成功setState(nextc);return true;}return false;
}

protected final boolean tryRelease(int releases) {int c = getState() - releases;if (Thread.currentThread() != getExclusiveOwnerThread())throw new IllegalMonitorStateException();boolean free = false;if (c == 0) {free = true;setExclusiveOwnerThread(null);}setState(c);return free;
}

public final void acquireShared(int arg) {if (tryAcquireShared(arg) < 0)doAcquireShared(arg);
}

public final boolean releaseShared(int arg) {if (tryReleaseShared(arg)) {doReleaseShared();return true;}return false;
}

protected int tryAcquireShared(int acquires) {return nonfairTryAcquireShared(acquires);
}final int nonfairTryAcquireShared(int acquires) {for (;;) {int available = getState();int remaining = available - acquires;if (remaining < 0 ||compareAndSetState(available, remaining))return remaining;}
}

protected final boolean tryReleaseShared(int releases) {for (;;) {int current = getState();int next = current + releases;if (next < current) // overflowthrow new Error("Maximum permit count exceeded");if (compareAndSetState(current, next))return true;}
}

private final ReentrantReadWriteLock.ReadLock readerLock;private final ReentrantReadWriteLock.WriteLock writerLock;final Sync sync;