package org.alfresco.repo.domain.locks; import org.alfresco.repo.lock.LockAcquisitionException; import org.alfresco.service.namespace.QName; /** * DAO services for alf_lock and related tables * * @author Derek Hulley * @since 3.2 */ public interface LockDAO { /** * 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 * * @param lockQName the unique name of the lock to acquire * @param lockToken the potential lock token (max 36 chars) * @param timeToLive the time (in milliseconds) that the lock must remain * * @throws LockAcquisitionException on failure */ void getLock(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. * * @param lockQName the unique name of the lock to update * @param lockToken the lock token for the lock held * @param timeToLive the new time to live (in milliseconds) * * @throws LockAcquisitionException on failure */ void refreshLock(QName lockQName, String lockToken, long timeToLive); /** * 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. * * @param lockQName the unique name of the lock to release * @param lockToken the current lock token * @param optimistic true if the release attempt is enough even * if the number of released locks was incorrect. * @return 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. */ boolean releaseLock(QName lockQName, String lockToken, boolean optimistic); }