jdk.util.concurrent.locks.AbstractQueuedLongSynchronizer — clojure-interop/java.util.concurrent 1.0.5

A version of AbstractQueuedSynchronizer 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 AbstractQueuedSynchronizer for usage notes and examples.

acquire clj

(acquire this arg)

Acquires in exclusive mode, ignoring interrupts. Implemented by invoking at least once tryAcquire(long), returning on success. Otherwise the thread is queued, possibly repeatedly blocking and unblocking, invoking tryAcquire(long) until success. This method can be used to implement method Lock.lock().

arg - the acquire argument. This value is conveyed to tryAcquire(long) but is otherwise uninterpreted and can represent anything you like. - long

acquire-interruptibly clj

(acquire-interruptibly this arg)

Acquires in exclusive mode, aborting if interrupted. Implemented by first checking interrupt status, then invoking at least once tryAcquire(long), returning on success. Otherwise the thread is queued, possibly repeatedly blocking and unblocking, invoking tryAcquire(long) until success or the thread is interrupted. This method can be used to implement method Lock.lockInterruptibly().

arg - the acquire argument. This value is conveyed to tryAcquire(long) but is otherwise uninterpreted and can represent anything you like. - long

throws: java.lang.InterruptedException - if the current thread is interrupted

acquire-shared clj

(acquire-shared this arg)

Acquires in shared mode, ignoring interrupts. Implemented by first invoking at least once tryAcquireShared(long), returning on success. Otherwise the thread is queued, possibly repeatedly blocking and unblocking, invoking tryAcquireShared(long) until success.

arg - the acquire argument. This value is conveyed to tryAcquireShared(long) but is otherwise uninterpreted and can represent anything you like. - long

acquire-shared-interruptibly clj

(acquire-shared-interruptibly this arg)

Acquires in shared mode, aborting if interrupted. Implemented by first checking interrupt status, then invoking at least once tryAcquireShared(long), returning on success. Otherwise the thread is queued, possibly repeatedly blocking and unblocking, invoking tryAcquireShared(long) until success or the thread is interrupted.

arg - the acquire argument. This value is conveyed to tryAcquireShared(long) but is otherwise uninterpreted and can represent anything you like. - long

throws: java.lang.InterruptedException - if the current thread is interrupted

get-exclusive-queued-threads clj

(get-exclusive-queued-threads this)

Returns a collection containing threads that may be waiting to acquire in exclusive mode. This has the same properties as getQueuedThreads() except that it only returns those threads waiting due to an exclusive acquire.

returns: the collection of threads - java.util.Collection<java.lang.Thread>

get-first-queued-thread clj

(get-first-queued-thread this)

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 - java.lang.Thread

get-queue-length clj

(get-queue-length this)

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 - int

get-queued-threads clj

(get-queued-threads this)

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 - java.util.Collection<java.lang.Thread>

get-shared-queued-threads clj

(get-shared-queued-threads this)

Returns a collection containing threads that may be waiting to acquire in shared mode. This has the same properties as getQueuedThreads() except that it only returns those threads waiting due to a shared acquire.

returns: the collection of threads - java.util.Collection<java.lang.Thread>

get-wait-queue-length clj

(get-wait-queue-length this 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 of the system state, not for synchronization control.

condition - the condition - java.util.concurrent.locks.AbstractQueuedLongSynchronizer$ConditionObject

returns: the estimated number of waiting threads - int

throws: java.lang.IllegalMonitorStateException - if exclusive synchronization is not held

get-waiting-threads clj

(get-waiting-threads this 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.

condition - the condition - java.util.concurrent.locks.AbstractQueuedLongSynchronizer$ConditionObject

returns: the collection of threads - java.util.Collection<java.lang.Thread>

throws: java.lang.IllegalMonitorStateException - if exclusive synchronization is not held

has-contended? clj

(has-contended? this)

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 - boolean

has-queued-predecessors? clj

(has-queued-predecessors? this)

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. Such a synchronizer's tryAcquire(long) method should return false, and its 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 } }

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 - boolean

has-queued-threads? clj

(has-queued-threads? this)

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 - boolean

has-waiters? clj

(has-waiters? this 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.

condition - the condition - java.util.concurrent.locks.AbstractQueuedLongSynchronizer$ConditionObject

returns: true if there are any waiting threads - boolean

throws: java.lang.IllegalMonitorStateException - if exclusive synchronization is not held

owns clj

(owns this condition)

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

condition - the condition - java.util.concurrent.locks.AbstractQueuedLongSynchronizer$ConditionObject

returns: true if owned - boolean

throws: java.lang.NullPointerException - if the condition is null

queued? clj

(queued? this thread)

Returns true if the given thread is currently queued.

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

thread - the thread - java.lang.Thread

returns: true if the given thread is on the queue - boolean

throws: java.lang.NullPointerException - if the thread is null

release clj

(release this arg)

Releases in exclusive mode. Implemented by unblocking one or more threads if tryRelease(long) returns true. This method can be used to implement method Lock.unlock().

arg - the release argument. This value is conveyed to tryRelease(long) but is otherwise uninterpreted and can represent anything you like. - long

returns: the value returned from tryRelease(long) - boolean

release-shared clj

(release-shared this arg)

Releases in shared mode. Implemented by unblocking one or more threads if tryReleaseShared(long) returns true.

arg - the release argument. This value is conveyed to tryReleaseShared(long) but is otherwise uninterpreted and can represent anything you like. - long

returns: the value returned from tryReleaseShared(long) - boolean

to-string clj

(to-string this)

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 getState(), and either "nonempty" or "empty" depending on whether the queue is empty.

returns: a string identifying this synchronizer, as well as its state - java.lang.String

try-acquire-nanos clj

(try-acquire-nanos this arg nanos-timeout)

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 tryAcquire(long), returning on success. Otherwise, the thread is queued, possibly repeatedly blocking and unblocking, invoking tryAcquire(long) until success or the thread is interrupted or the timeout elapses. This method can be used to implement method Lock.tryLock(long, TimeUnit).

arg - the acquire argument. This value is conveyed to tryAcquire(long) but is otherwise uninterpreted and can represent anything you like. - long nanos-timeout - the maximum number of nanoseconds to wait - long

returns: true if acquired; false if timed out - boolean

throws: java.lang.InterruptedException - if the current thread is interrupted

try-acquire-shared-nanos clj

(try-acquire-shared-nanos this arg nanos-timeout)

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 tryAcquireShared(long), returning on success. Otherwise, the thread is queued, possibly repeatedly blocking and unblocking, invoking tryAcquireShared(long) until success or the thread is interrupted or the timeout elapses.

arg - the acquire argument. This value is conveyed to tryAcquireShared(long) but is otherwise uninterpreted and can represent anything you like. - long nanos-timeout - the maximum number of nanoseconds to wait - long

returns: true if acquired; false if timed out - boolean

throws: java.lang.InterruptedException - if the current thread is interrupted