# AbstractQueuedLongSynchronizer

public abstract class **AbstractQueuedLongSynchronizer** extends [AbstractOwnableSynchronizer](https://developers.google.com/j2objc/javadoc/jre/reference/java/util/concurrent/locks/AbstractOwnableSynchronizer.html)  
implements [Serializable](https://developers.google.com/j2objc/javadoc/jre/reference/java/io/Serializable.html) A version of `https://developers.google.com/j2objc/javadoc/jre/reference/java/util/concurrent/locks/AbstractQueuedSynchronizer.html` in
which synchronization state is maintained as a `long`.
This class has exactly the same structure, properties, and methods
as `AbstractQueuedSynchronizer` with the exception
that all state-related parameters and results are defined
as `long` rather than `int`. This class
may be useful when creating synchronizers such as
multilevel locks and barriers that require
64 bits of state.

See `https://developers.google.com/j2objc/javadoc/jre/reference/java/util/concurrent/locks/AbstractQueuedSynchronizer.html` for usage
notes and examples.

### Nested Class Summary

|---|---|---|---|
| class | [AbstractQueuedLongSynchronizer.ConditionObject](https://developers.google.com/j2objc/javadoc/jre/reference/java/util/concurrent/locks/AbstractQueuedLongSynchronizer.ConditionObject.html) || Condition implementation for a `https://developers.google.com/j2objc/javadoc/jre/reference/java/util/concurrent/locks/AbstractQueuedLongSynchronizer.html` serving as the basis of a `https://developers.google.com/j2objc/javadoc/jre/reference/java/util/concurrent/locks/Lock.html` implementation. |

### Protected Constructor Summary

|---|---|
|   | [AbstractQueuedLongSynchronizer](https://developers.google.com/j2objc/javadoc/jre/reference/java/util/concurrent/locks/AbstractQueuedLongSynchronizer.html#AbstractQueuedLongSynchronizer())() Creates a new `AbstractQueuedLongSynchronizer` instance with initial synchronization state of zero. |

### Public Method Summary

|---|---|
| final void | [acquire](https://developers.google.com/j2objc/javadoc/jre/reference/java/util/concurrent/locks/AbstractQueuedLongSynchronizer.html#acquire(long))(long arg) Acquires in exclusive mode, ignoring interrupts. |
| final void | [acquireInterruptibly](https://developers.google.com/j2objc/javadoc/jre/reference/java/util/concurrent/locks/AbstractQueuedLongSynchronizer.html#acquireInterruptibly(long))(long arg) Acquires in exclusive mode, aborting if interrupted. |
| final void | [acquireShared](https://developers.google.com/j2objc/javadoc/jre/reference/java/util/concurrent/locks/AbstractQueuedLongSynchronizer.html#acquireShared(long))(long arg) Acquires in shared mode, ignoring interrupts. |
| final void | [acquireSharedInterruptibly](https://developers.google.com/j2objc/javadoc/jre/reference/java/util/concurrent/locks/AbstractQueuedLongSynchronizer.html#acquireSharedInterruptibly(long))(long arg) Acquires in shared mode, aborting if interrupted. |
| final [Collection](https://developers.google.com/j2objc/javadoc/jre/reference/java/util/Collection.html)\<Thread\> | [getExclusiveQueuedThreads](https://developers.google.com/j2objc/javadoc/jre/reference/java/util/concurrent/locks/AbstractQueuedLongSynchronizer.html#getExclusiveQueuedThreads())() Returns a collection containing threads that may be waiting to acquire in exclusive mode. |
| final Thread | [getFirstQueuedThread](https://developers.google.com/j2objc/javadoc/jre/reference/java/util/concurrent/locks/AbstractQueuedLongSynchronizer.html#getFirstQueuedThread())() Returns the first (longest-waiting) thread in the queue, or `null` if no threads are currently queued. |
| final int | [getQueueLength](https://developers.google.com/j2objc/javadoc/jre/reference/java/util/concurrent/locks/AbstractQueuedLongSynchronizer.html#getQueueLength())() Returns an estimate of the number of threads waiting to acquire. |
| final [Collection](https://developers.google.com/j2objc/javadoc/jre/reference/java/util/Collection.html)\<Thread\> | [getQueuedThreads](https://developers.google.com/j2objc/javadoc/jre/reference/java/util/concurrent/locks/AbstractQueuedLongSynchronizer.html#getQueuedThreads())() Returns a collection containing threads that may be waiting to acquire. |
| final [Collection](https://developers.google.com/j2objc/javadoc/jre/reference/java/util/Collection.html)\<Thread\> | [getSharedQueuedThreads](https://developers.google.com/j2objc/javadoc/jre/reference/java/util/concurrent/locks/AbstractQueuedLongSynchronizer.html#getSharedQueuedThreads())() Returns a collection containing threads that may be waiting to acquire in shared mode. |
| final int | [getWaitQueueLength](https://developers.google.com/j2objc/javadoc/jre/reference/java/util/concurrent/locks/AbstractQueuedLongSynchronizer.html#getWaitQueueLength(java.util.concurrent.locks.AbstractQueuedLongSynchronizer.ConditionObject))([AbstractQueuedLongSynchronizer.ConditionObject](https://developers.google.com/j2objc/javadoc/jre/reference/java/util/concurrent/locks/AbstractQueuedLongSynchronizer.ConditionObject.html) condition) Returns an estimate of the number of threads waiting on the given condition associated with this synchronizer. |
| final [Collection](https://developers.google.com/j2objc/javadoc/jre/reference/java/util/Collection.html)\<Thread\> | [getWaitingThreads](https://developers.google.com/j2objc/javadoc/jre/reference/java/util/concurrent/locks/AbstractQueuedLongSynchronizer.html#getWaitingThreads(java.util.concurrent.locks.AbstractQueuedLongSynchronizer.ConditionObject))([AbstractQueuedLongSynchronizer.ConditionObject](https://developers.google.com/j2objc/javadoc/jre/reference/java/util/concurrent/locks/AbstractQueuedLongSynchronizer.ConditionObject.html) condition) Returns a collection containing those threads that may be waiting on the given condition associated with this synchronizer. |
| final boolean | [hasContended](https://developers.google.com/j2objc/javadoc/jre/reference/java/util/concurrent/locks/AbstractQueuedLongSynchronizer.html#hasContended())() Queries whether any threads have ever contended to acquire this synchronizer; that is, if an acquire method has ever blocked. |
| final boolean | [hasQueuedPredecessors](https://developers.google.com/j2objc/javadoc/jre/reference/java/util/concurrent/locks/AbstractQueuedLongSynchronizer.html#hasQueuedPredecessors())() Queries whether any threads have been waiting to acquire longer than the current thread. |
| final boolean | [hasQueuedThreads](https://developers.google.com/j2objc/javadoc/jre/reference/java/util/concurrent/locks/AbstractQueuedLongSynchronizer.html#hasQueuedThreads())() Queries whether any threads are waiting to acquire. |
| final boolean | [hasWaiters](https://developers.google.com/j2objc/javadoc/jre/reference/java/util/concurrent/locks/AbstractQueuedLongSynchronizer.html#hasWaiters(java.util.concurrent.locks.AbstractQueuedLongSynchronizer.ConditionObject))([AbstractQueuedLongSynchronizer.ConditionObject](https://developers.google.com/j2objc/javadoc/jre/reference/java/util/concurrent/locks/AbstractQueuedLongSynchronizer.ConditionObject.html) condition) Queries whether any threads are waiting on the given condition associated with this synchronizer. |
| final boolean | [isQueued](https://developers.google.com/j2objc/javadoc/jre/reference/java/util/concurrent/locks/AbstractQueuedLongSynchronizer.html#isQueued(java.lang.Thread))(Thread thread) Returns true if the given thread is currently queued. |
| final boolean | [owns](https://developers.google.com/j2objc/javadoc/jre/reference/java/util/concurrent/locks/AbstractQueuedLongSynchronizer.html#owns(java.util.concurrent.locks.AbstractQueuedLongSynchronizer.ConditionObject))([AbstractQueuedLongSynchronizer.ConditionObject](https://developers.google.com/j2objc/javadoc/jre/reference/java/util/concurrent/locks/AbstractQueuedLongSynchronizer.ConditionObject.html) condition) Queries whether the given ConditionObject uses this synchronizer as its lock. |
| final boolean | [release](https://developers.google.com/j2objc/javadoc/jre/reference/java/util/concurrent/locks/AbstractQueuedLongSynchronizer.html#release(long))(long arg) Releases in exclusive mode. |
| final boolean | [releaseShared](https://developers.google.com/j2objc/javadoc/jre/reference/java/util/concurrent/locks/AbstractQueuedLongSynchronizer.html#releaseShared(long))(long arg) Releases in shared mode. |
| [String](https://developers.google.com/j2objc/javadoc/jre/reference/java/lang/String.html) | [toString](https://developers.google.com/j2objc/javadoc/jre/reference/java/util/concurrent/locks/AbstractQueuedLongSynchronizer.html#toString())() Returns a string identifying this synchronizer, as well as its state. |
| final boolean | [tryAcquireNanos](https://developers.google.com/j2objc/javadoc/jre/reference/java/util/concurrent/locks/AbstractQueuedLongSynchronizer.html#tryAcquireNanos(long,%20long))(long arg, long nanosTimeout) Attempts to acquire in exclusive mode, aborting if interrupted, and failing if the given timeout elapses. |
| final boolean | [tryAcquireSharedNanos](https://developers.google.com/j2objc/javadoc/jre/reference/java/util/concurrent/locks/AbstractQueuedLongSynchronizer.html#tryAcquireSharedNanos(long,%20long))(long arg, long nanosTimeout) Attempts to acquire in shared mode, aborting if interrupted, and failing if the given timeout elapses. |

### Protected Method Summary

|---|---|
| final boolean | [compareAndSetState](https://developers.google.com/j2objc/javadoc/jre/reference/java/util/concurrent/locks/AbstractQueuedLongSynchronizer.html#compareAndSetState(long,%20long))(long expect, long update) Atomically sets synchronization state to the given updated value if the current state value equals the expected value. |
| final long | [getState](https://developers.google.com/j2objc/javadoc/jre/reference/java/util/concurrent/locks/AbstractQueuedLongSynchronizer.html#getState())() Returns the current value of synchronization state. |
| boolean | [isHeldExclusively](https://developers.google.com/j2objc/javadoc/jre/reference/java/util/concurrent/locks/AbstractQueuedLongSynchronizer.html#isHeldExclusively())() Returns `true` if synchronization is held exclusively with respect to the current (calling) thread. |
| final void | [setState](https://developers.google.com/j2objc/javadoc/jre/reference/java/util/concurrent/locks/AbstractQueuedLongSynchronizer.html#setState(long))(long newState) Sets the value of synchronization state. |
| boolean | [tryAcquire](https://developers.google.com/j2objc/javadoc/jre/reference/java/util/concurrent/locks/AbstractQueuedLongSynchronizer.html#tryAcquire(long))(long arg) Attempts to acquire in exclusive mode. |
| long | [tryAcquireShared](https://developers.google.com/j2objc/javadoc/jre/reference/java/util/concurrent/locks/AbstractQueuedLongSynchronizer.html#tryAcquireShared(long))(long arg) Attempts to acquire in shared mode. |
| boolean | [tryRelease](https://developers.google.com/j2objc/javadoc/jre/reference/java/util/concurrent/locks/AbstractQueuedLongSynchronizer.html#tryRelease(long))(long arg) Attempts to set the state to reflect a release in exclusive mode. |
| boolean | [tryReleaseShared](https://developers.google.com/j2objc/javadoc/jre/reference/java/util/concurrent/locks/AbstractQueuedLongSynchronizer.html#tryReleaseShared(long))(long arg) Attempts to set the state to reflect a release in shared mode. |

### Inherited Method Summary

From class [java.util.concurrent.locks.AbstractOwnableSynchronizer](https://developers.google.com/j2objc/javadoc/jre/reference/java/util/concurrent/locks/AbstractOwnableSynchronizer.html)

|---|---|
| final Thread | [getExclusiveOwnerThread](https://developers.google.com/j2objc/javadoc/jre/reference/java/util/concurrent/locks/AbstractOwnableSynchronizer.html#getExclusiveOwnerThread())() Returns the thread last set by `setExclusiveOwnerThread`, or `null` if never set. |
| final void | [setExclusiveOwnerThread](https://developers.google.com/j2objc/javadoc/jre/reference/java/util/concurrent/locks/AbstractOwnableSynchronizer.html#setExclusiveOwnerThread(java.lang.Thread))(Thread thread) Sets the thread that currently owns exclusive access. |

From class [java.lang.Object](https://developers.google.com/j2objc/javadoc/jre/reference/java/lang/Object.html)

|---|---|
| [Object](https://developers.google.com/j2objc/javadoc/jre/reference/java/lang/Object.html) | [clone](https://developers.google.com/j2objc/javadoc/jre/reference/java/lang/Object.html#clone())() Creates and returns a copy of this `Object`. |
| boolean | [equals](https://developers.google.com/j2objc/javadoc/jre/reference/java/lang/Object.html#equals(java.lang.Object))([Object](https://developers.google.com/j2objc/javadoc/jre/reference/java/lang/Object.html) obj) Compares this instance with the specified object and indicates if they are equal. |
| void | [finalize](https://developers.google.com/j2objc/javadoc/jre/reference/java/lang/Object.html#finalize())() Invoked when the garbage collector has detected that this instance is no longer reachable. |
| final [Class](https://developers.google.com/j2objc/javadoc/jre/reference/java/lang/Class.html)\<?\> | [getClass](https://developers.google.com/j2objc/javadoc/jre/reference/java/lang/Object.html#getClass())() Returns the unique instance of `https://developers.google.com/j2objc/javadoc/jre/reference/java/lang/Class.html` that represents this object's class. |
| int | [hashCode](https://developers.google.com/j2objc/javadoc/jre/reference/java/lang/Object.html#hashCode())() Returns an integer hash code for this object. |
| final void | [notify](https://developers.google.com/j2objc/javadoc/jre/reference/java/lang/Object.html#notify())() Causes a thread which is waiting on this object's monitor (by means of calling one of the `wait()` methods) to be woken up. |
| final void | [notifyAll](https://developers.google.com/j2objc/javadoc/jre/reference/java/lang/Object.html#notifyAll())() Causes all threads which are waiting on this object's monitor (by means of calling one of the `wait()` methods) to be woken up. |
| [String](https://developers.google.com/j2objc/javadoc/jre/reference/java/lang/String.html) | [toString](https://developers.google.com/j2objc/javadoc/jre/reference/java/lang/Object.html#toString())() Returns a string containing a concise, human-readable description of this object. |
| final void | [wait](https://developers.google.com/j2objc/javadoc/jre/reference/java/lang/Object.html#wait(long,%20int))(long timeout, int nanos) Causes the calling thread to wait until another thread calls the `notify()` or `notifyAll()` method of this object or until the specified timeout expires. |
| final void | [wait](https://developers.google.com/j2objc/javadoc/jre/reference/java/lang/Object.html#wait(long))(long timeout) Causes the calling thread to wait until another thread calls the `notify()` or `notifyAll()` method of this object or until the specified timeout expires. |
| final void | [wait](https://developers.google.com/j2objc/javadoc/jre/reference/java/lang/Object.html#wait())() Causes the calling thread to wait until another thread calls the `notify()` or `notifyAll()` method of this object. |

## Protected Constructors

#### protected
**AbstractQueuedLongSynchronizer**
()

Creates a new `AbstractQueuedLongSynchronizer` instance
with initial synchronization state of zero.

## Public Methods

#### public final void
**acquire**
(long arg)

Acquires in exclusive mode, ignoring interrupts. Implemented
by invoking at least once `https://developers.google.com/j2objc/javadoc/jre/reference/java/util/concurrent/locks/AbstractQueuedLongSynchronizer.html#tryAcquire(long)`,
returning on success. Otherwise the thread is queued, possibly
repeatedly blocking and unblocking, invoking `https://developers.google.com/j2objc/javadoc/jre/reference/java/util/concurrent/locks/AbstractQueuedLongSynchronizer.html#tryAcquire(long)` until success. This method can be used
to implement method `https://developers.google.com/j2objc/javadoc/jre/reference/java/util/concurrent/locks/Lock.html#lock()`.

##### Parameters

| arg | the acquire argument. This value is conveyed to `https://developers.google.com/j2objc/javadoc/jre/reference/java/util/concurrent/locks/AbstractQueuedLongSynchronizer.html#tryAcquire(long)` but is otherwise uninterpreted and can represent anything you like. |
|---|---|

#### public final void
**acquireInterruptibly**
(long arg)

Acquires in exclusive mode, aborting if interrupted.
Implemented by first checking interrupt status, then invoking
at least once `https://developers.google.com/j2objc/javadoc/jre/reference/java/util/concurrent/locks/AbstractQueuedLongSynchronizer.html#tryAcquire(long)`, returning on
success. Otherwise the thread is queued, possibly repeatedly
blocking and unblocking, invoking `https://developers.google.com/j2objc/javadoc/jre/reference/java/util/concurrent/locks/AbstractQueuedLongSynchronizer.html#tryAcquire(long)`
until success or the thread is interrupted. This method can be
used to implement method `https://developers.google.com/j2objc/javadoc/jre/reference/java/util/concurrent/locks/Lock.html#lockInterruptibly()`.

##### Parameters

| arg | the acquire argument. This value is conveyed to `https://developers.google.com/j2objc/javadoc/jre/reference/java/util/concurrent/locks/AbstractQueuedLongSynchronizer.html#tryAcquire(long)` but is otherwise uninterpreted and can represent anything you like. |
|---|---|

##### Throws

| [InterruptedException](https://developers.google.com/j2objc/javadoc/jre/reference/java/lang/InterruptedException.html) | if the current thread is interrupted |
|---|---|

#### public final void
**acquireShared**
(long arg)

Acquires in shared mode, ignoring interrupts. Implemented by
first invoking at least once `https://developers.google.com/j2objc/javadoc/jre/reference/java/util/concurrent/locks/AbstractQueuedLongSynchronizer.html#tryAcquireShared(long)`,
returning on success. Otherwise the thread is queued, possibly
repeatedly blocking and unblocking, invoking `https://developers.google.com/j2objc/javadoc/jre/reference/java/util/concurrent/locks/AbstractQueuedLongSynchronizer.html#tryAcquireShared(long)` until success.

##### Parameters

| arg | the acquire argument. This value is conveyed to `https://developers.google.com/j2objc/javadoc/jre/reference/java/util/concurrent/locks/AbstractQueuedLongSynchronizer.html#tryAcquireShared(long)` but is otherwise uninterpreted and can represent anything you like. |
|---|---|

#### public final void
**acquireSharedInterruptibly**
(long arg)

Acquires in shared mode, aborting if interrupted. Implemented
by first checking interrupt status, then invoking at least once
`https://developers.google.com/j2objc/javadoc/jre/reference/java/util/concurrent/locks/AbstractQueuedLongSynchronizer.html#tryAcquireShared(long)`, returning on success. Otherwise the
thread is queued, possibly repeatedly blocking and unblocking,
invoking `https://developers.google.com/j2objc/javadoc/jre/reference/java/util/concurrent/locks/AbstractQueuedLongSynchronizer.html#tryAcquireShared(long)` until success or the thread
is interrupted.

##### Parameters

| arg | the acquire argument. This value is conveyed to `https://developers.google.com/j2objc/javadoc/jre/reference/java/util/concurrent/locks/AbstractQueuedLongSynchronizer.html#tryAcquireShared(long)` but is otherwise uninterpreted and can represent anything you like. |
|---|---|

##### Throws

| [InterruptedException](https://developers.google.com/j2objc/javadoc/jre/reference/java/lang/InterruptedException.html) | if the current thread is interrupted |
|---|---|

#### public final [Collection](https://developers.google.com/j2objc/javadoc/jre/reference/java/util/Collection.html)\<Thread\>
**getExclusiveQueuedThreads**
()

Returns a collection containing threads that may be waiting to
acquire in exclusive mode. This has the same properties
as `https://developers.google.com/j2objc/javadoc/jre/reference/java/util/concurrent/locks/AbstractQueuedLongSynchronizer.html#getQueuedThreads()` except that it only returns
those threads waiting due to an exclusive acquire.

##### Returns

- the collection of threads

#### public final Thread
**getFirstQueuedThread**
()

Returns the first (longest-waiting) thread in the queue, or
`null` if no threads are currently queued.

In this implementation, this operation normally returns in
constant time, but may iterate upon contention if other threads are
concurrently modifying the queue.

##### Returns

- the first (longest-waiting) thread in the queue, or `null` if no threads are currently queued

#### public final int
**getQueueLength**
()

Returns an estimate of the number of threads waiting to
acquire. The value is only an estimate because the number of
threads may change dynamically while this method traverses
internal data structures. This method is designed for use in
monitoring system state, not for synchronization control.

##### Returns

- the estimated number of threads waiting to acquire

#### public final [Collection](https://developers.google.com/j2objc/javadoc/jre/reference/java/util/Collection.html)\<Thread\>
**getQueuedThreads**
()

Returns a collection containing threads that may be waiting to
acquire. Because the actual set of threads may change
dynamically while constructing this result, the returned
collection is only a best-effort estimate. The elements of the
returned collection are in no particular order. This method is
designed to facilitate construction of subclasses that provide
more extensive monitoring facilities.

##### Returns

- the collection of threads

#### public final [Collection](https://developers.google.com/j2objc/javadoc/jre/reference/java/util/Collection.html)\<Thread\>
**getSharedQueuedThreads**
()

Returns a collection containing threads that may be waiting to
acquire in shared mode. This has the same properties
as `https://developers.google.com/j2objc/javadoc/jre/reference/java/util/concurrent/locks/AbstractQueuedLongSynchronizer.html#getQueuedThreads()` except that it only returns
those threads waiting due to a shared acquire.

##### Returns

- the collection of threads

#### public final int
**getWaitQueueLength**
([AbstractQueuedLongSynchronizer.ConditionObject](https://developers.google.com/j2objc/javadoc/jre/reference/java/util/concurrent/locks/AbstractQueuedLongSynchronizer.ConditionObject.html) condition)

Returns an estimate of the number of threads waiting on the
given condition associated with this synchronizer. Note that
because timeouts and interrupts may occur at any time, the
estimate serves only as an upper bound on the actual number of
waiters. This method is designed for use in monitoring system
state, not for synchronization control.

##### Parameters

| condition | the condition |
|---|---|

##### Returns

- the estimated number of waiting threads

##### Throws

| [IllegalMonitorStateException](https://developers.google.com/j2objc/javadoc/jre/reference/java/lang/IllegalMonitorStateException.html) | if exclusive synchronization is not held |
| [IllegalArgumentException](https://developers.google.com/j2objc/javadoc/jre/reference/java/lang/IllegalArgumentException.html) | if the given condition is not associated with this synchronizer |
| [NullPointerException](https://developers.google.com/j2objc/javadoc/jre/reference/java/lang/NullPointerException.html) | if the condition is null |
|---|---|

#### public final [Collection](https://developers.google.com/j2objc/javadoc/jre/reference/java/util/Collection.html)\<Thread\>
**getWaitingThreads**
([AbstractQueuedLongSynchronizer.ConditionObject](https://developers.google.com/j2objc/javadoc/jre/reference/java/util/concurrent/locks/AbstractQueuedLongSynchronizer.ConditionObject.html) condition)

Returns a collection containing those threads that may be
waiting on the given condition associated with this
synchronizer. Because the actual set of threads may change
dynamically while constructing this result, the returned
collection is only a best-effort estimate. The elements of the
returned collection are in no particular order.

##### Parameters

| condition | the condition |
|---|---|

##### Returns

- the collection of threads

##### Throws

| [IllegalMonitorStateException](https://developers.google.com/j2objc/javadoc/jre/reference/java/lang/IllegalMonitorStateException.html) | if exclusive synchronization is not held |
| [IllegalArgumentException](https://developers.google.com/j2objc/javadoc/jre/reference/java/lang/IllegalArgumentException.html) | if the given condition is not associated with this synchronizer |
| [NullPointerException](https://developers.google.com/j2objc/javadoc/jre/reference/java/lang/NullPointerException.html) | if the condition is null |
|---|---|

#### public final boolean
**hasContended**
()

Queries whether any threads have ever contended to acquire this
synchronizer; that is, if an acquire method has ever blocked.

In this implementation, this operation returns in
constant time.

##### Returns

- `true` if there has ever been contention

#### public final boolean
**hasQueuedPredecessors**
()

Queries whether any threads have been waiting to acquire longer
than the current thread.

An invocation of this method is equivalent to (but may be
more efficient than):

     getFirstQueuedThread() != Thread.currentThread()
       && hasQueuedThreads()

Note that because cancellations due to interrupts and
timeouts may occur at any time, a `true` return does not
guarantee that some other thread will acquire before the current
thread. Likewise, it is possible for another thread to win a
race to enqueue after this method has returned `false`,
due to the queue being empty.

This method is designed to be used by a fair synchronizer to
avoid [barging](https://developers.google.com/j2objc/javadoc/jre/reference/java/util/concurrent/locks/AbstractQueuedSynchronizer#barging).
Such a synchronizer's `https://developers.google.com/j2objc/javadoc/jre/reference/java/util/concurrent/locks/AbstractQueuedLongSynchronizer.html#tryAcquire(long)` method should return
`false`, and its `https://developers.google.com/j2objc/javadoc/jre/reference/java/util/concurrent/locks/AbstractQueuedLongSynchronizer.html#tryAcquireShared(long)` method should
return a negative value, if this method returns `true`
(unless this is a reentrant acquire). For example, the `tryAcquire` method for a fair, reentrant, exclusive mode
synchronizer might look like this:

     protected boolean tryAcquire(int arg) {
       if (isHeldExclusively()) {
         // A reentrant acquire; increment hold count
         return true;
       } else if (hasQueuedPredecessors()) {
         return false;
       } else {
         // try to acquire normally
       }
     }

<br />

##### Returns

- `true` if there is a queued thread preceding the current thread, and `false` if the current thread is at the head of the queue or the queue is empty

#### public final boolean
**hasQueuedThreads**
()

Queries whether any threads are waiting to acquire. Note that
because cancellations due to interrupts and timeouts may occur
at any time, a `true` return does not guarantee that any
other thread will ever acquire.

In this implementation, this operation returns in
constant time.

##### Returns

- `true` if there may be other threads waiting to acquire

#### public final boolean
**hasWaiters**
([AbstractQueuedLongSynchronizer.ConditionObject](https://developers.google.com/j2objc/javadoc/jre/reference/java/util/concurrent/locks/AbstractQueuedLongSynchronizer.ConditionObject.html) condition)

Queries whether any threads are waiting on the given condition
associated with this synchronizer. Note that because timeouts
and interrupts may occur at any time, a `true` return
does not guarantee that a future `signal` will awaken
any threads. This method is designed primarily for use in
monitoring of the system state.

##### Parameters

| condition | the condition |
|---|---|

##### Returns

- `true` if there are any waiting threads

##### Throws

| [IllegalMonitorStateException](https://developers.google.com/j2objc/javadoc/jre/reference/java/lang/IllegalMonitorStateException.html) | if exclusive synchronization is not held |
| [IllegalArgumentException](https://developers.google.com/j2objc/javadoc/jre/reference/java/lang/IllegalArgumentException.html) | if the given condition is not associated with this synchronizer |
| [NullPointerException](https://developers.google.com/j2objc/javadoc/jre/reference/java/lang/NullPointerException.html) | if the condition is null |
|---|---|

#### public final boolean
**isQueued**
(Thread thread)

Returns true if the given thread is currently queued.

This implementation traverses the queue to determine
presence of the given thread.

##### Parameters

| thread | the thread |
|---|---|

##### Returns

- `true` if the given thread is on the queue

##### Throws

| [NullPointerException](https://developers.google.com/j2objc/javadoc/jre/reference/java/lang/NullPointerException.html) | if the thread is null |
|---|---|

#### public final boolean
**owns**
([AbstractQueuedLongSynchronizer.ConditionObject](https://developers.google.com/j2objc/javadoc/jre/reference/java/util/concurrent/locks/AbstractQueuedLongSynchronizer.ConditionObject.html) condition)

Queries whether the given ConditionObject
uses this synchronizer as its lock.

##### Parameters

| condition | the condition |
|---|---|

##### Returns

- `true` if owned

##### Throws

| [NullPointerException](https://developers.google.com/j2objc/javadoc/jre/reference/java/lang/NullPointerException.html) | if the condition is null |
|---|---|

#### public final boolean
**release**
(long arg)

Releases in exclusive mode. Implemented by unblocking one or
more threads if `https://developers.google.com/j2objc/javadoc/jre/reference/java/util/concurrent/locks/AbstractQueuedLongSynchronizer.html#tryRelease(long)` returns true.
This method can be used to implement method `https://developers.google.com/j2objc/javadoc/jre/reference/java/util/concurrent/locks/Lock.html#unlock()`.

##### Parameters

| arg | the release argument. This value is conveyed to `https://developers.google.com/j2objc/javadoc/jre/reference/java/util/concurrent/locks/AbstractQueuedLongSynchronizer.html#tryRelease(long)` but is otherwise uninterpreted and can represent anything you like. |
|---|---|

##### Returns

- the value returned from `https://developers.google.com/j2objc/javadoc/jre/reference/java/util/concurrent/locks/AbstractQueuedLongSynchronizer.html#tryRelease(long)`

#### public final boolean
**releaseShared**
(long arg)

Releases in shared mode. Implemented by unblocking one or more
threads if `https://developers.google.com/j2objc/javadoc/jre/reference/java/util/concurrent/locks/AbstractQueuedLongSynchronizer.html#tryReleaseShared(long)` returns true.

##### Parameters

| arg | the release argument. This value is conveyed to `https://developers.google.com/j2objc/javadoc/jre/reference/java/util/concurrent/locks/AbstractQueuedLongSynchronizer.html#tryReleaseShared(long)` but is otherwise uninterpreted and can represent anything you like. |
|---|---|

##### Returns

- the value returned from `https://developers.google.com/j2objc/javadoc/jre/reference/java/util/concurrent/locks/AbstractQueuedLongSynchronizer.html#tryReleaseShared(long)`

#### public [String](https://developers.google.com/j2objc/javadoc/jre/reference/java/lang/String.html)
**toString**
()

Returns a string identifying this synchronizer, as well as its state.
The state, in brackets, includes the String `"State ="`
followed by the current value of `https://developers.google.com/j2objc/javadoc/jre/reference/java/util/concurrent/locks/AbstractQueuedLongSynchronizer.html#getState()`, and either
`"nonempty"` or `"empty"` depending on whether the
queue is empty.

##### Returns

- a string identifying this synchronizer, as well as its state

#### public final boolean
**tryAcquireNanos**
(long arg, long nanosTimeout)

Attempts to acquire in exclusive mode, aborting if interrupted,
and failing if the given timeout elapses. Implemented by first
checking interrupt status, then invoking at least once `https://developers.google.com/j2objc/javadoc/jre/reference/java/util/concurrent/locks/AbstractQueuedLongSynchronizer.html#tryAcquire(long)`, returning on success. Otherwise, the thread is
queued, possibly repeatedly blocking and unblocking, invoking
`https://developers.google.com/j2objc/javadoc/jre/reference/java/util/concurrent/locks/AbstractQueuedLongSynchronizer.html#tryAcquire(long)` until success or the thread is interrupted
or the timeout elapses. This method can be used to implement
method `https://developers.google.com/j2objc/javadoc/jre/reference/java/util/concurrent/locks/Lock.html#tryLock(long,%20java.util.concurrent.TimeUnit)`.

##### Parameters

| arg | the acquire argument. This value is conveyed to `https://developers.google.com/j2objc/javadoc/jre/reference/java/util/concurrent/locks/AbstractQueuedLongSynchronizer.html#tryAcquire(long)` but is otherwise uninterpreted and can represent anything you like. |
| nanosTimeout | the maximum number of nanoseconds to wait |
|---|---|

##### Returns

- `true` if acquired; `false` if timed out

##### Throws

| [InterruptedException](https://developers.google.com/j2objc/javadoc/jre/reference/java/lang/InterruptedException.html) | if the current thread is interrupted |
|---|---|

#### public final boolean
**tryAcquireSharedNanos**
(long arg, long nanosTimeout)

Attempts to acquire in shared mode, aborting if interrupted, and
failing if the given timeout elapses. Implemented by first
checking interrupt status, then invoking at least once `https://developers.google.com/j2objc/javadoc/jre/reference/java/util/concurrent/locks/AbstractQueuedLongSynchronizer.html#tryAcquireShared(long)`, returning on success. Otherwise, the
thread is queued, possibly repeatedly blocking and unblocking,
invoking `https://developers.google.com/j2objc/javadoc/jre/reference/java/util/concurrent/locks/AbstractQueuedLongSynchronizer.html#tryAcquireShared(long)` until success or the thread
is interrupted or the timeout elapses.

##### Parameters

| arg | the acquire argument. This value is conveyed to `https://developers.google.com/j2objc/javadoc/jre/reference/java/util/concurrent/locks/AbstractQueuedLongSynchronizer.html#tryAcquireShared(long)` but is otherwise uninterpreted and can represent anything you like. |
| nanosTimeout | the maximum number of nanoseconds to wait |
|---|---|

##### Returns

- `true` if acquired; `false` if timed out

##### Throws

| [InterruptedException](https://developers.google.com/j2objc/javadoc/jre/reference/java/lang/InterruptedException.html) | if the current thread is interrupted |
|---|---|

## Protected Methods

#### protected final boolean
**compareAndSetState**
(long expect, long update)

Atomically sets synchronization state to the given updated
value if the current state value equals the expected value.
This operation has memory semantics of a `volatile` read
and write.

##### Parameters

| expect | the expected value |
| update | the new value |
|---|---|

##### Returns

- `true` if successful. False return indicates that the actual value was not equal to the expected value.

#### protected final long
**getState**
()

Returns the current value of synchronization state.
This operation has memory semantics of a `volatile` read.

##### Returns

- current state value

#### protected boolean
**isHeldExclusively**
()

Returns `true` if synchronization is held exclusively with
respect to the current (calling) thread. This method is invoked
upon each call to a non-waiting `https://developers.google.com/j2objc/javadoc/jre/reference/java/util/concurrent/locks/AbstractQueuedLongSynchronizer.ConditionObject.html` method.
(Waiting methods instead invoke `https://developers.google.com/j2objc/javadoc/jre/reference/java/util/concurrent/locks/AbstractQueuedLongSynchronizer.html#release(long)`.)

The default implementation throws `https://developers.google.com/j2objc/javadoc/jre/reference/java/lang/UnsupportedOperationException.html`. This method is invoked
internally only within `https://developers.google.com/j2objc/javadoc/jre/reference/java/util/concurrent/locks/AbstractQueuedLongSynchronizer.ConditionObject.html` methods, so need
not be defined if conditions are not used.

##### Returns

- `true` if synchronization is held exclusively; `false` otherwise

##### Throws

| [UnsupportedOperationException](https://developers.google.com/j2objc/javadoc/jre/reference/java/lang/UnsupportedOperationException.html) | if conditions are not supported |
|---|---|

#### protected final void
**setState**
(long newState)

Sets the value of synchronization state.
This operation has memory semantics of a `volatile` write.

##### Parameters

| newState | the new state value |
|---|---|

#### protected boolean
**tryAcquire**
(long arg)

Attempts to acquire in exclusive mode. This method should query
if the state of the object permits it to be acquired in the
exclusive mode, and if so to acquire it.

This method is always invoked by the thread performing
acquire. If this method reports failure, the acquire method
may queue the thread, if it is not already queued, until it is
signalled by a release from some other thread. This can be used
to implement method `https://developers.google.com/j2objc/javadoc/jre/reference/java/util/concurrent/locks/Lock.html#tryLock()`.

The default
implementation throws `https://developers.google.com/j2objc/javadoc/jre/reference/java/lang/UnsupportedOperationException.html`.

##### Parameters

| arg | the acquire argument. This value is always the one passed to an acquire method, or is the value saved on entry to a condition wait. The value is otherwise uninterpreted and can represent anything you like. |
|---|---|

##### Returns

- `true` if successful. Upon success, this object has been acquired.

##### Throws

| [IllegalMonitorStateException](https://developers.google.com/j2objc/javadoc/jre/reference/java/lang/IllegalMonitorStateException.html) | if acquiring would place this synchronizer in an illegal state. This exception must be thrown in a consistent fashion for synchronization to work correctly. |
| [UnsupportedOperationException](https://developers.google.com/j2objc/javadoc/jre/reference/java/lang/UnsupportedOperationException.html) | if exclusive mode is not supported |
|---|---|

#### protected long
**tryAcquireShared**
(long arg)

Attempts to acquire in shared mode. This method should query if
the state of the object permits it to be acquired in the shared
mode, and if so to acquire it.

This method is always invoked by the thread performing
acquire. If this method reports failure, the acquire method
may queue the thread, if it is not already queued, until it is
signalled by a release from some other thread.

The default implementation throws `https://developers.google.com/j2objc/javadoc/jre/reference/java/lang/UnsupportedOperationException.html`.

##### Parameters

| arg | the acquire argument. This value is always the one passed to an acquire method, or is the value saved on entry to a condition wait. The value is otherwise uninterpreted and can represent anything you like. |
|---|---|

##### Returns

- a negative value on failure; zero if acquisition in shared mode succeeded but no subsequent shared-mode acquire can succeed; and a positive value if acquisition in shared mode succeeded and subsequent shared-mode acquires might also succeed, in which case a subsequent waiting thread must check availability. (Support for three different return values enables this method to be used in contexts where acquires only sometimes act exclusively.) Upon success, this object has been acquired.

##### Throws

| [IllegalMonitorStateException](https://developers.google.com/j2objc/javadoc/jre/reference/java/lang/IllegalMonitorStateException.html) | if acquiring would place this synchronizer in an illegal state. This exception must be thrown in a consistent fashion for synchronization to work correctly. |
| [UnsupportedOperationException](https://developers.google.com/j2objc/javadoc/jre/reference/java/lang/UnsupportedOperationException.html) | if shared mode is not supported |
|---|---|

#### protected boolean
**tryRelease**
(long arg)

Attempts to set the state to reflect a release in exclusive
mode.

This method is always invoked by the thread performing release.

The default implementation throws
`https://developers.google.com/j2objc/javadoc/jre/reference/java/lang/UnsupportedOperationException.html`.

##### Parameters

| arg | the release argument. This value is always the one passed to a release method, or the current state value upon entry to a condition wait. The value is otherwise uninterpreted and can represent anything you like. |
|---|---|

##### Returns

- `true` if this object is now in a fully released state, so that any waiting threads may attempt to acquire; and `false` otherwise.

##### Throws

| [IllegalMonitorStateException](https://developers.google.com/j2objc/javadoc/jre/reference/java/lang/IllegalMonitorStateException.html) | if releasing would place this synchronizer in an illegal state. This exception must be thrown in a consistent fashion for synchronization to work correctly. |
| [UnsupportedOperationException](https://developers.google.com/j2objc/javadoc/jre/reference/java/lang/UnsupportedOperationException.html) | if exclusive mode is not supported |
|---|---|

#### protected boolean
**tryReleaseShared**
(long arg)

Attempts to set the state to reflect a release in shared mode.

This method is always invoked by the thread performing release.

The default implementation throws
`https://developers.google.com/j2objc/javadoc/jre/reference/java/lang/UnsupportedOperationException.html`.

##### Parameters

| arg | the release argument. This value is always the one passed to a release method, or the current state value upon entry to a condition wait. The value is otherwise uninterpreted and can represent anything you like. |
|---|---|

##### Returns

- `true` if this release of shared mode may permit a waiting acquire (shared or exclusive) to succeed; and `false` otherwise

##### Throws

| [IllegalMonitorStateException](https://developers.google.com/j2objc/javadoc/jre/reference/java/lang/IllegalMonitorStateException.html) | if releasing would place this synchronizer in an illegal state. This exception must be thrown in a consistent fashion for synchronization to work correctly. |
| [UnsupportedOperationException](https://developers.google.com/j2objc/javadoc/jre/reference/java/lang/UnsupportedOperationException.html) | if shared mode is not supported |
|---|---|