Package com.ibm.asyncutil.locks

Class FairAsyncReadWriteLock

java.lang.Object

com.ibm.asyncutil.locks.FairAsyncReadWriteLock

All Implemented Interfaces:

AsyncReadWriteLock

Direct Known Subclasses:

FairAsyncStampedLock

public class FairAsyncReadWriteLock
extends Object
implements AsyncReadWriteLock

An implementation of the AsyncReadWriteLock interface which enforces reader/writer fairness -- i.e. new readers will queue behind waiting writers

Nested Class Summary

Nested classes/interfaces inherited from interface com.ibm.asyncutil.locks.AsyncReadWriteLock

AsyncReadWriteLock.ReadLockToken, AsyncReadWriteLock.WriteLockToken

Constructor Summary

Constructors

Constructor	Description
FairAsyncReadWriteLock()

Method Summary

Modifier and Type	Method	Description
CompletionStage<AsyncReadWriteLock.ReadLockToken>	acquireReadLock()	Acquires this read lock.
CompletionStage<AsyncReadWriteLock.WriteLockToken>	acquireWriteLock()	Exclusively acquires this write lock.
Optional<AsyncReadWriteLock.ReadLockToken>	tryReadLock()	Attempt to immediately acquire the read lock, returning a populated Optional if the lock is not currently held by a writer and there are no writers queued in waiting (i.e.
Optional<AsyncReadWriteLock.WriteLockToken>	tryWriteLock()	Attempts to immediately acquire the write lock, returning a populated Optional if the lock is not currently held by a writer or any readers.

Methods inherited from interface com.ibm.asyncutil.locks.AsyncReadWriteLock

create, createFair

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

FairAsyncReadWriteLock

public FairAsyncReadWriteLock()

Method Detail

acquireReadLock

public final CompletionStage<AsyncReadWriteLock.ReadLockToken> acquireReadLock()

Description copied from interface: AsyncReadWriteLock

Acquires this read lock. The returned stage will complete when the lock is no longer exclusively held by a writer, and the read lock has been acquired. The stage may already be complete if the write lock is not currently held.

The AsyncReadWriteLock.ReadLockToken held by the returned stage is used to release the read lock after it has been acquired and the read-lock-protected action has completed.

Specified by:

acquireReadLock in interface AsyncReadWriteLock

Returns:

A CompletionStage which will complete with a AsyncReadWriteLock.ReadLockToken when the read lock has been acquired

tryReadLock

public final Optional<AsyncReadWriteLock.ReadLockToken> tryReadLock()

Attempt to immediately acquire the read lock, returning a populated Optional if the lock is not currently held by a writer and there are no writers queued in waiting (i.e. this acquire is "fair" and will not barge ahead of waiting writers).

Specified by:

tryReadLock in interface AsyncReadWriteLock

Returns:

An Optional holding a AsyncReadWriteLock.ReadLockToken if the lock is not held by a writer; otherwise an empty Optional

acquireWriteLock

public final CompletionStage<AsyncReadWriteLock.WriteLockToken> acquireWriteLock()

Description copied from interface: AsyncReadWriteLock

Exclusively acquires this write lock. The returned stage will complete when the lock is no longer held by any readers or another writer, and the write lock has been exclusively acquired. The stage may already be complete if no locks are currently held.

The AsyncReadWriteLock.WriteLockToken held by the returned stage is used to release the write lock after it has been acquired and the write-lock-protected action has completed.

Specified by:

acquireWriteLock in interface AsyncReadWriteLock

Returns:

A CompletionStage which will complete with a AsyncReadWriteLock.WriteLockToken when the write lock has been exclusively acquired

tryWriteLock

public final Optional<AsyncReadWriteLock.WriteLockToken> tryWriteLock()

Description copied from interface: AsyncReadWriteLock

Attempts to immediately acquire the write lock, returning a populated Optional if the lock is not currently held by a writer or any readers.

Specified by:

tryWriteLock in interface AsyncReadWriteLock

Returns:

An Optional holding a AsyncReadWriteLock.WriteLockToken if the lock is not held by a writer or any readers; otherwise an empty Optional