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java.util.concurrent.locks

public Class ReentrantLock

extends Object
implements Lock, Serializable
Class Inheritance
All Implemented Interfaces
java.io.Serializable, java.util.concurrent.locks.Lock
Known Direct Subclasses
jdk.internal.loader.NativeLibraries.CountedLock, java.util.concurrent.ConcurrentHashMap.Segment
Imports
java.util.Collection, java.util.concurrent.TimeUnit, jdk.internal.vm.annotation.ReservedStackAccess
A reentrant mutual exclusion Lock with the same basic behavior and semantics as the implicit monitor lock accessed using synchronized methods and statements, but with extended capabilities.

A ReentrantLock is owned by the thread last successfully locking, but not yet unlocking it. A thread invoking lock will return, successfully acquiring the lock, when the lock is not owned by another thread. The method will return immediately if the current thread already owns the lock. This can be checked using methods isHeldByCurrentThread, and getHoldCount.

The constructor for this class accepts an optional fairness parameter. When set true, under contention, locks favor granting access to the longest-waiting thread. Otherwise this lock does not guarantee any particular access order. Programs using fair locks accessed by many threads may display lower overall throughput (i.e., are slower; often much slower) than those using the default setting, but have smaller variances in times to obtain locks and guarantee lack of starvation. Note however, that fairness of locks does not guarantee fairness of thread scheduling. Thus, one of many threads using a fair lock may obtain it multiple times in succession while other active threads are not progressing and not currently holding the lock. Also note that the untimed tryLock() method does not honor the fairness setting. It will succeed if the lock is available even if other threads are waiting.

It is recommended practice to always immediately follow a call to lock with a try block, and to always immediately call unlock as the first statement in the finally block, as follows: 

 class X {
  private final ReentrantLock lock = new ReentrantLock();
  // ...

  public void m() {
    lock.lock();  // lock() as the last statement before the try block
    try {
      // ... method body
    } finally {
      lock.unlock(); // unlock() as the first statement in the finally block
    }
  }
}

In addition to implementing the Lock interface, this class defines a number of public and protected methods for inspecting the state of the lock. Some of these methods are only useful for instrumentation and monitoring.

Serialization of this class behaves in the same way as built-in locks: a deserialized lock is in the unlocked state, regardless of its state when serialized.

This lock supports a maximum of 2147483647 recursive locks by the same thread. Attempts to exceed this limit result in Error throws from locking methods.

Author
Doug Lea
Since
1.5

Nested and Inner Type Summary

Modifier and TypeClass and Description
pack-priv static class
ReentrantLock.FairSync

Sync object for fair locks

pack-priv static class
ReentrantLock.NonfairSync

Sync object for non-fair locks

pack-priv abstract static class
ReentrantLock.Sync

Base of synchronization control for this lock.

Field Summary

Modifier and TypeField and Description
private static final long
serialVersionUID

private final ReentrantLock.Sync
sync

Constructor Summary

AccessConstructor and Description
public
ReentrantLock()

Creates an instance of ReentrantLock.

public
ReentrantLock(boolean
true if this lock should use a fair ordering policy
fair)

Creates an instance of ReentrantLock with the given fairness policy.

Method Summary

Modifier and TypeMethod and Description
public int

Returns:

the number of holds on this lock by the current thread, or zero if this lock is not held by the current thread
getHoldCount()

Queries the number of holds on this lock by the current thread.

protected Thread

Returns:

the owner, or null if not owned
getOwner()

Returns the thread that currently owns this lock, or null if not owned.

protected Collection<Thread>

Returns:

the collection of threads
getQueuedThreads()

Returns a collection containing threads that may be waiting to acquire this lock.

public final int

Returns:

the estimated number of threads waiting for this lock
getQueueLength()

Returns an estimate of the number of threads waiting to acquire this lock.

protected Collection<Thread>

Returns:

the collection of threads
getWaitingThreads(Condition
the condition
condition)

Returns a collection containing those threads that may be waiting on the given condition associated with this lock.

public int

Returns:

the estimated number of waiting threads
getWaitQueueLength(Condition
the condition
condition)

Returns an estimate of the number of threads waiting on the given condition associated with this lock.

public final boolean

Returns:

true if the given thread is queued waiting for this lock
hasQueuedThread(Thread
the thread
thread)

Queries whether the given thread is waiting to acquire this lock.

public final boolean

Returns:

true if there may be other threads waiting to acquire the lock
hasQueuedThreads()

Queries whether any threads are waiting to acquire this lock.

public boolean

Returns:

true if there are any waiting threads
hasWaiters(Condition
the condition
condition)

Queries whether any threads are waiting on the given condition associated with this lock.

public final boolean

Returns:

true if this lock has fairness set true
isFair()

Returns true if this lock has fairness set true.

public boolean

Returns:

true if current thread holds this lock and false otherwise
isHeldByCurrentThread()

Queries if this lock is held by the current thread.

public boolean

Returns:

true if any thread holds this lock and false otherwise
isLocked()

Queries if this lock is held by any thread.

public void
lock()

Implements java.util.concurrent.locks.Lock.lock.

Acquires the lock.

public void
lockInterruptibly()

Implements java.util.concurrent.locks.Lock.lockInterruptibly.

Acquires the lock unless the current thread is interrupted.

public Condition

Returns:

the Condition object
newCondition()

Implements java.util.concurrent.locks.Lock.newCondition.

Returns a Condition instance for use with this Lock instance.

public String

Returns:

a string identifying this lock, as well as its lock state
toString()

Overrides java.lang.Object.toString.

Returns a string identifying this lock, as well as its lock state.

public boolean

Returns:

true if the lock was free and was acquired by the current thread, or the lock was already held by the current thread; and false otherwise
tryLock()

Implements java.util.concurrent.locks.Lock.tryLock.

Acquires the lock only if it is not held by another thread at the time of invocation.

public boolean

Returns:

true if the lock was free and was acquired by the current thread, or the lock was already held by the current thread; and false if the waiting time elapsed before the lock could be acquired
tryLock(long
the time to wait for the lock
timeout, TimeUnit
the time unit of the timeout argument
unit)

Implements java.util.concurrent.locks.Lock.tryLock.

Acquires the lock if it is not held by another thread within the given waiting time and the current thread has not been interrupted.

public void
unlock()

Implements java.util.concurrent.locks.Lock.unlock.

Attempts to release this lock.

Inherited from java.lang.Object:
cloneequalsfinalizegetClasshashCodenotifynotifyAllwaitwaitwait

Field Detail

serialVersionUIDback to summary
private static final long serialVersionUID
syncback to summary
private final ReentrantLock.Sync sync

Constructor Detail

ReentrantLockback to summary
public ReentrantLock()

Creates an instance of ReentrantLock. This is equivalent to using ReentrantLock(false).

ReentrantLockback to summary
public ReentrantLock(boolean fair)

Creates an instance of ReentrantLock with the given fairness policy.

Parameters
fair:boolean

true if this lock should use a fair ordering policy

Method Detail

getHoldCountback to summary
public int getHoldCount()

Queries the number of holds on this lock by the current thread.

A thread has a hold on a lock for each lock action that is not matched by an unlock action.

The hold count information is typically only used for testing and debugging purposes. For example, if a certain section of code should not be entered with the lock already held then we can assert that fact: 

 class X {
  final ReentrantLock lock = new ReentrantLock();
  // ...
  public void m() {
    assert lock.getHoldCount() == 0;
    lock.lock();
    try {
      // ... method body
    } finally {
      lock.unlock();
    }
  }
}
Returns:int

the number of holds on this lock by the current thread, or zero if this lock is not held by the current thread

getOwnerback to summary
protected Thread getOwner()

Returns the thread that currently owns this lock, or null if not owned. When this method is called by a thread that is not the owner, the return value reflects a best-effort approximation of current lock status. For example, the owner may be momentarily null even if there are threads trying to acquire the lock but have not yet done so. This method is designed to facilitate construction of subclasses that provide more extensive lock monitoring facilities.

Returns:Thread

the owner, or null if not owned

getQueuedThreadsback to summary
protected Collection<Thread> getQueuedThreads()

Returns a collection containing threads that may be waiting to acquire this lock. 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:Collection<Thread>

the collection of threads

getQueueLengthback to summary
public final int getQueueLength()

Returns an estimate of the number of threads waiting to acquire this lock. 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:int

the estimated number of threads waiting for this lock

getWaitingThreadsback to summary
protected Collection<Thread> getWaitingThreads(Condition condition)

Returns a collection containing those threads that may be waiting on the given condition associated with this lock. 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 condition monitoring facilities.

Parameters
condition:Condition

the condition

Returns:Collection<Thread>

the collection of threads

Exceptions
IllegalMonitorStateException:
if this lock is not held
IllegalArgumentException:
if the given condition is not associated with this lock
NullPointerException:
if the condition is null
getWaitQueueLengthback to summary
public int getWaitQueueLength(Condition condition)

Returns an estimate of the number of threads waiting on the given condition associated with this lock. 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 of the system state, not for synchronization control.

Parameters
condition:Condition

the condition

Returns:int

the estimated number of waiting threads

Exceptions
IllegalMonitorStateException:
if this lock is not held
IllegalArgumentException:
if the given condition is not associated with this lock
NullPointerException:
if the condition is null
hasQueuedThreadback to summary
public final boolean hasQueuedThread(Thread thread)

Queries whether the given thread is waiting to acquire this lock. Note that because cancellations may occur at any time, a true return does not guarantee that this thread will ever acquire this lock. This method is designed primarily for use in monitoring of the system state.

Parameters
thread:Thread

the thread

Returns:boolean

true if the given thread is queued waiting for this lock

Exceptions
NullPointerException:
if the thread is null
hasQueuedThreadsback to summary
public final boolean hasQueuedThreads()

Queries whether any threads are waiting to acquire this lock. Note that because cancellations may occur at any time, a true return does not guarantee that any other thread will ever acquire this lock. This method is designed primarily for use in monitoring of the system state.

Returns:boolean

true if there may be other threads waiting to acquire the lock

hasWaitersback to summary
public boolean hasWaiters(Condition condition)

Queries whether any threads are waiting on the given condition associated with this lock. 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:Condition

the condition

Returns:boolean

true if there are any waiting threads

Exceptions
IllegalMonitorStateException:
if this lock is not held
IllegalArgumentException:
if the given condition is not associated with this lock
NullPointerException:
if the condition is null
isFairback to summary
public final boolean isFair()

Returns true if this lock has fairness set true.

Returns:boolean

true if this lock has fairness set true

isHeldByCurrentThreadback to summary
public boolean isHeldByCurrentThread()

Queries if this lock is held by the current thread.

Analogous to the Thread#holdsLock(Object) method for built-in monitor locks, this method is typically used for debugging and testing. For example, a method that should only be called while a lock is held can assert that this is the case: 

 class X {
  final ReentrantLock lock = new ReentrantLock();
  // ...

  public void m() {
      assert lock.isHeldByCurrentThread();
      // ... method body
  }
}

It can also be used to ensure that a reentrant lock is used in a non-reentrant manner, for example: 

 class X {
  final ReentrantLock lock = new ReentrantLock();
  // ...

  public void m() {
      assert !lock.isHeldByCurrentThread();
      lock.lock();
      try {
          // ... method body
      } finally {
          lock.unlock();
      }
  }
}
Returns:boolean

true if current thread holds this lock and false otherwise

isLockedback to summary
public boolean isLocked()

Queries if this lock is held by any thread. This method is designed for use in monitoring of the system state, not for synchronization control.

Returns:boolean

true if any thread holds this lock and false otherwise

lockback to summary
public void lock()

Implements java.util.concurrent.locks.Lock.lock.

Acquires the lock.

Acquires the lock if it is not held by another thread and returns immediately, setting the lock hold count to one.

If the current thread already holds the lock then the hold count is incremented by one and the method returns immediately.

If the lock is held by another thread then the current thread becomes disabled for thread scheduling purposes and lies dormant until the lock has been acquired, at which time the lock hold count is set to one.

lockInterruptiblyback to summary
public void lockInterruptibly() throws InterruptedException

Implements java.util.concurrent.locks.Lock.lockInterruptibly.

Acquires the lock unless the current thread is interrupted.

Acquires the lock if it is not held by another thread and returns immediately, setting the lock hold count to one.

If the current thread already holds this lock then the hold count is incremented by one and the method returns immediately.

If the lock is held by another thread then the current thread becomes disabled for thread scheduling purposes and lies dormant until one of two things happens:

  • The lock is acquired by the current thread; or
  • Some other thread interrupts the current thread.

If the lock is acquired by the current thread then the lock hold count is set to one.

If the current thread:

  • has its interrupted status set on entry to this method; or
  • is interrupted while acquiring the lock,
then InterruptedException is thrown and the current thread's interrupted status is cleared.

In this implementation, as this method is an explicit interruption point, preference is given to responding to the interrupt over normal or reentrant acquisition of the lock.

Exceptions
InterruptedException:
if the current thread is interrupted
newConditionback to summary
public Condition newCondition()

Implements java.util.concurrent.locks.Lock.newCondition.

Returns a Condition instance for use with this Lock instance.

The returned Condition instance supports the same usages as do the Object monitor methods (wait, notify, and notifyAll) when used with the built-in monitor lock.

  • If this lock is not held when any of the Condition waiting or signalling methods are called, then an IllegalMonitorStateException is thrown.
  • When the condition waiting methods are called the lock is released and, before they return, the lock is reacquired and the lock hold count restored to what it was when the method was called.
  • If a thread is interrupted while waiting then the wait will terminate, an InterruptedException will be thrown, and the thread's interrupted status will be cleared.
  • Waiting threads are signalled in FIFO order.
  • The ordering of lock reacquisition for threads returning from waiting methods is the same as for threads initially acquiring the lock, which is in the default case not specified, but for fair locks favors those threads that have been waiting the longest.
Returns:Condition

the Condition object

toStringback to summary
public String toString()

Overrides java.lang.Object.toString.

Returns a string identifying this lock, as well as its lock state. The state, in brackets, includes either the String "Unlocked" or the String "Locked by" followed by the name of the owning thread.

Returns:String

a string identifying this lock, as well as its lock state

tryLockback to summary
public boolean tryLock()

Implements java.util.concurrent.locks.Lock.tryLock.

Acquires the lock only if it is not held by another thread at the time of invocation.

Acquires the lock if it is not held by another thread and returns immediately with the value true, setting the lock hold count to one. Even when this lock has been set to use a fair ordering policy, a call to tryLock() will immediately acquire the lock if it is available, whether or not other threads are currently waiting for the lock. This "barging" behavior can be useful in certain circumstances, even though it breaks fairness. If you want to honor the fairness setting for this lock, then use tryLock(0, TimeUnit.SECONDS) which is almost equivalent (it also detects interruption).

If the current thread already holds this lock then the hold count is incremented by one and the method returns true.

If the lock is held by another thread then this method will return immediately with the value false.

Returns:boolean

true if the lock was free and was acquired by the current thread, or the lock was already held by the current thread; and false otherwise

tryLockback to summary
public boolean tryLock(long timeout, TimeUnit unit) throws InterruptedException

Implements java.util.concurrent.locks.Lock.tryLock.

Acquires the lock if it is not held by another thread within the given waiting time and the current thread has not been interrupted.

Acquires the lock if it is not held by another thread and returns immediately with the value true, setting the lock hold count to one. If this lock has been set to use a fair ordering policy then an available lock will not be acquired if any other threads are waiting for the lock. This is in contrast to the tryLock() method. If you want a timed tryLock that does permit barging on a fair lock then combine the timed and un-timed forms together: 

 if (lock.tryLock() ||
    lock.tryLock(timeout, unit)) {
  ...
}

If the current thread already holds this lock then the hold count is incremented by one and the method returns true.

If the lock is held by another thread then the current thread becomes disabled for thread scheduling purposes and lies dormant until one of three things happens:

  • The lock is acquired by the current thread; or
  • Some other thread interrupts the current thread; or
  • The specified waiting time elapses

If the lock is acquired then the value true is returned and the lock hold count is set to one.

If the current thread:

  • has its interrupted status set on entry to this method; or
  • is interrupted while acquiring the lock,
then InterruptedException is thrown and the current thread's interrupted status is cleared.

If the specified waiting time elapses then the value false is returned. If the time is less than or equal to zero, the method will not wait at all.

In this implementation, as this method is an explicit interruption point, preference is given to responding to the interrupt over normal or reentrant acquisition of the lock, and over reporting the elapse of the waiting time.

Parameters
timeout:long

the time to wait for the lock

unit:TimeUnit

the time unit of the timeout argument

Returns:boolean

true if the lock was free and was acquired by the current thread, or the lock was already held by the current thread; and false if the waiting time elapsed before the lock could be acquired

Exceptions
InterruptedException:
if the current thread is interrupted
NullPointerException:
if the time unit is null
unlockback to summary
public void unlock()

Implements java.util.concurrent.locks.Lock.unlock.

Attempts to release this lock.

If the current thread is the holder of this lock then the hold count is decremented. If the hold count is now zero then the lock is released. If the current thread is not the holder of this lock then IllegalMonitorStateException is thrown.

Exceptions
IllegalMonitorStateException:
if the current thread does not hold this lock
java.util.concurrent.locks back to summary

pack-priv final Class ReentrantLock.FairSync

extends Sync
Class Inheritance
Sync object for fair locks

Field Summary

Modifier and TypeField and Description
private static final long
serialVersionUID

Hides java.util.concurrent.locks.ReentrantLock.Sync.serialVersionUID.

Constructor Summary

AccessConstructor and Description
pack-priv
FairSync()

Method Summary

Modifier and TypeMethod and Description
pack-priv final boolean
initialTryLock()

Implements abstract java.util.concurrent.locks.ReentrantLock.Sync.initialTryLock.

Acquires only if reentrant or queue is empty.

protected final boolean
tryAcquire(int acquires)

Overrides java.util.concurrent.locks.AbstractQueuedSynchronizer.tryAcquire.

Acquires only if thread is first waiter or empty

Inherited from java.util.concurrent.locks.ReentrantLock.Sync:
getHoldCountgetOwnerisHeldExclusivelyisLockedlocklockInterruptiblynewConditiontryLocktryLockNanostryRelease

Field Detail

serialVersionUIDback to summary
private static final long serialVersionUID

Hides java.util.concurrent.locks.ReentrantLock.Sync.serialVersionUID.

Constructor Detail

FairSyncback to summary
pack-priv FairSync()

Method Detail

initialTryLockback to summary
pack-priv final boolean initialTryLock()

Implements abstract java.util.concurrent.locks.ReentrantLock.Sync.initialTryLock.

Acquires only if reentrant or queue is empty.

tryAcquireback to summary
protected final boolean tryAcquire(int acquires)

Overrides java.util.concurrent.locks.AbstractQueuedSynchronizer.tryAcquire.

Acquires only if thread is first waiter or empty

java.util.concurrent.locks back to summary

pack-priv final Class ReentrantLock.NonfairSync

extends Sync
Class Inheritance
Sync object for non-fair locks

Field Summary

Modifier and TypeField and Description
private static final long
serialVersionUID

Hides java.util.concurrent.locks.ReentrantLock.Sync.serialVersionUID.

Constructor Summary

AccessConstructor and Description
pack-priv
NonfairSync()

Method Summary

Modifier and TypeMethod and Description
pack-priv final boolean
initialTryLock()

Implements abstract java.util.concurrent.locks.ReentrantLock.Sync.initialTryLock.

Checks for reentrancy and acquires if lock immediately available under fair vs nonfair rules.

protected final boolean
tryAcquire(int acquires)

Overrides java.util.concurrent.locks.AbstractQueuedSynchronizer.tryAcquire.

Acquire for non-reentrant cases after initialTryLock prescreen

Inherited from java.util.concurrent.locks.ReentrantLock.Sync:
getHoldCountgetOwnerisHeldExclusivelyisLockedlocklockInterruptiblynewConditiontryLocktryLockNanostryRelease

Field Detail

serialVersionUIDback to summary
private static final long serialVersionUID

Hides java.util.concurrent.locks.ReentrantLock.Sync.serialVersionUID.

Constructor Detail

NonfairSyncback to summary
pack-priv NonfairSync()

Method Detail

initialTryLockback to summary
pack-priv final boolean initialTryLock()

Implements abstract java.util.concurrent.locks.ReentrantLock.Sync.initialTryLock.

Doc from java.util.concurrent.locks.ReentrantLock.Sync.initialTryLock.

Checks for reentrancy and acquires if lock immediately available under fair vs nonfair rules. Locking methods perform initialTryLock check before relaying to corresponding AQS acquire methods.

tryAcquireback to summary
protected final boolean tryAcquire(int acquires)

Overrides java.util.concurrent.locks.AbstractQueuedSynchronizer.tryAcquire.

Acquire for non-reentrant cases after initialTryLock prescreen

java.util.concurrent.locks back to summary

pack-priv abstract Class ReentrantLock.Sync

extends AbstractQueuedSynchronizer
Class Inheritance
Known Direct Subclasses
java.util.concurrent.locks.ReentrantLock.NonfairSync, java.util.concurrent.locks.ReentrantLock.FairSync
Base of synchronization control for this lock. Subclassed into fair and nonfair versions below. Uses AQS state to represent the number of holds on the lock.

Field Summary

Modifier and TypeField and Description
private static final long
serialVersionUID

Hides java.util.concurrent.locks.AbstractQueuedSynchronizer.serialVersionUID.

Inherited from java.util.concurrent.locks.AbstractQueuedSynchronizer:
CANCELLEDCONDWAITING

Constructor Summary

AccessConstructor and Description
pack-priv
Sync()

Method Summary

Modifier and TypeMethod and Description
pack-priv final int
getHoldCount()

pack-priv final Thread
getOwner()

pack-priv abstract boolean
initialTryLock()

Checks for reentrancy and acquires if lock immediately available under fair vs nonfair rules.

protected final boolean
isHeldExclusively()

Overrides java.util.concurrent.locks.AbstractQueuedSynchronizer.isHeldExclusively.

Returns true if synchronization is held exclusively with respect to the current (calling) thread.

pack-priv final boolean
isLocked()

pack-priv final void
lock()

pack-priv final void
lockInterruptibly()

pack-priv final AbstractQueuedSynchronizer.ConditionObject
newCondition()

private void
readObject(ObjectInputStream s)

Reconstitutes the instance from a stream (that is, deserializes it).

pack-priv final boolean
tryLock()

Performs non-fair tryLock.

pack-priv final boolean
tryLockNanos(long nanos)

protected final boolean
tryRelease(int releases)

Overrides java.util.concurrent.locks.AbstractQueuedSynchronizer.tryRelease.

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

Inherited from java.util.concurrent.locks.AbstractQueuedSynchronizer:
acquireacquireacquireInterruptiblyacquireSharedacquireSharedInterruptiblyapparentlyFirstQueuedIsExclusivecompareAndSetStateenqueuegetExclusiveQueuedThreadsgetFirstQueuedThreadgetQueuedThreadsgetQueueLengthgetSharedQueuedThreadsgetStategetWaitingThreadsgetWaitQueueLengthhasContendedhasQueuedPredecessorshasQueuedThreadshasWaitersisEnqueuedisQueuedownsreleasereleaseSharedsetStatetoStringtryAcquiretryAcquireNanostryAcquireSharedtryAcquireSharedNanostryReleaseShared

Field Detail

serialVersionUIDback to summary
private static final long serialVersionUID

Hides java.util.concurrent.locks.AbstractQueuedSynchronizer.serialVersionUID.

Constructor Detail

Syncback to summary
pack-priv Sync()

Method Detail

getHoldCountback to summary
pack-priv final int getHoldCount()
getOwnerback to summary
pack-priv final Thread getOwner()
initialTryLockback to summary
pack-priv abstract boolean initialTryLock()

Checks for reentrancy and acquires if lock immediately available under fair vs nonfair rules. Locking methods perform initialTryLock check before relaying to corresponding AQS acquire methods.

isHeldExclusivelyback to summary
protected final boolean isHeldExclusively()

Overrides java.util.concurrent.locks.AbstractQueuedSynchronizer.isHeldExclusively.

Doc from java.util.concurrent.locks.AbstractQueuedSynchronizer.isHeldExclusively.

Returns true if synchronization is held exclusively with respect to the current (calling) thread. This method is invoked upon each call to a ConditionObject method.

The default implementation throws UnsupportedOperationException. This method is invoked internally only within ConditionObject methods, so need not be defined if conditions are not used.

isLockedback to summary
pack-priv final boolean isLocked()
lockback to summary
pack-priv final void lock()
Annotations
@ReservedStackAccess
lockInterruptiblyback to summary
pack-priv final void lockInterruptibly() throws InterruptedException
Annotations
@ReservedStackAccess
newConditionback to summary
pack-priv final AbstractQueuedSynchronizer.ConditionObject newCondition()
readObjectback to summary
private void readObject(ObjectInputStream s) throws IOException, ClassNotFoundException

Reconstitutes the instance from a stream (that is, deserializes it).

tryLockback to summary
pack-priv final boolean tryLock()

Performs non-fair tryLock.

Annotations
@ReservedStackAccess
tryLockNanosback to summary
pack-priv final boolean tryLockNanos(long nanos) throws InterruptedException
Annotations
@ReservedStackAccess
tryReleaseback to summary
protected final boolean tryRelease(int releases)

Overrides java.util.concurrent.locks.AbstractQueuedSynchronizer.tryRelease.

Doc from java.util.concurrent.locks.AbstractQueuedSynchronizer.tryRelease.

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 UnsupportedOperationException.

Annotations
@ReservedStackAccess