org.alfresco.repo.domain.locks

Interface LockDAO

All Known Implementing Classes:

AbstractLockDAOImpl, LockDAOImpl

public interface LockDAO

DAO services for alf_lock and related tables

Since:

3.2

Author:

Derek Hulley

Method Summary

Modifier and Type	Method and Description
void	getLock(org.alfresco.service.namespace.QName lockQName, String lockToken, long timeToLive) Acquire a given exclusive lock, assigning it (and any implicitly shared locks) a timeout.
void	refreshLock(org.alfresco.service.namespace.QName lockQName, String lockToken, long timeToLive) Refresh a held lock.
boolean	releaseLock(org.alfresco.service.namespace.QName lockQName, String lockToken, boolean optimistic) Release a lock.

Method Detail

getLock

void getLock(org.alfresco.service.namespace.QName lockQName,
             String lockToken,
             long timeToLive)

Acquire a given exclusive lock, assigning it (and any implicitly shared locks) a timeout. All shared locks are implicitly taken as well.

A lock can be re-taken if it has expired and if the lock token has not changed

Parameters:

lockQName - the unique name of the lock to acquire

lockToken - the potential lock token (max 36 chars)

timeToLive - the time (in milliseconds) that the lock must remain

Throws:

LockAcquisitionException - on failure

refreshLock

void refreshLock(org.alfresco.service.namespace.QName lockQName,
                 String lockToken,
                 long timeToLive)

Refresh a held lock. This is successful if the lock in question still exists and if the lock token has not changed. Lock expiry does not prevent the lock from being refreshed.

Parameters:

lockQName - the unique name of the lock to update

lockToken - the lock token for the lock held

timeToLive - the new time to live (in milliseconds)

Throws:

LockAcquisitionException - on failure

releaseLock

boolean releaseLock(org.alfresco.service.namespace.QName lockQName,
                    String lockToken,
                    boolean optimistic)

Release a lock. The lock token must still apply and all the shared and exclusive locks need to still be present, unless the method is optimistic, in which case the unlock is considered to be a success.
Lock expiration does not prevent this operation from succeeding.

Note: Failure to release a lock due to a exception condition is dealt with by passing the exception out.

Parameters:

lockQName - the unique name of the lock to release

lockToken - the current lock token

optimistic - true if the release attempt is enough even if the number of released locks was incorrect.

Returns:

Returns true if all the required locks were (still) held under the lock token and were valid at the time of release, otherwise false

Throws:

LockAcquisitionException - if the number of locks released was incorrect and pessimistic release is requested.