Package com.ibm.asyncutil.locks

Interface AsyncLock

All Known Implementing Classes:

FairAsyncLock

public interface AsyncLock

An asynchronously acquirable mutual exclusion lock.

Implementations will specify whether their lock acquisition is fair or not; this interface does not define this requirement.

Nested Class Summary

Nested Classes

Modifier and Type	Interface	Description
static interface	AsyncLock.LockToken	A lock token indicating that the associated lock has been exclusively acquired.

Method Summary

Modifier and Type	Method	Description
CompletionStage<AsyncLock.LockToken>	acquireLock()	Exclusively acquires this lock.
static AsyncLock	create()	Creates an AsyncLock
static AsyncLock	createFair()	Creates a fair AsyncLock
Optional<AsyncLock.LockToken>	tryLock()	Attempts to immediately acquire the lock, returning a populated Optional if the lock is not currently held.

Method Detail

acquireLock

CompletionStage<AsyncLock.LockToken> acquireLock()

Exclusively acquires this lock. The returned stage will complete when the lock is exclusively acquired by this caller. The stage may already be complete if the lock was not held.

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

Returns:

A CompletionStage which will complete with a AsyncLock.LockToken when the lock has been exclusively acquired

tryLock

Optional<AsyncLock.LockToken> tryLock()

Attempts to immediately acquire the lock, returning a populated Optional if the lock is not currently held.

Returns:

An Optional holding a AsyncLock.LockToken if the lock is not held; otherwise an empty Optional

create

static AsyncLock create()

Creates an AsyncLock

The returned lock is only guaranteed to meet the requirements of AsyncLock; in particular, no guarantee of fairness is provided.

Returns:

a new AsyncLock

createFair

static AsyncLock createFair()

Creates a fair AsyncLock

Returns:

a new AsyncLock with a fair implementation