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389f996f29
- Provides transaction-aware locking - Post-transaction cleanup is automatically done - Retrying for lock acquisition is handled internally as well - Downgraded the lock concurrency tests for the build machine (maybe 50 threads was too much) - Deadlock tests added for the high-level locking git-svn-id: https://svn.alfresco.com/repos/alfresco-enterprise/alfresco/HEAD/root@13968 c4b6b30b-aa2e-2d43-bbcb-ca4b014f7261
88 lines
4.4 KiB
Java
88 lines
4.4 KiB
Java
/*
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* Copyright (C) 2005-2009 Alfresco Software Limited.
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; either version 2
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* of the License, or (at your option) any later version.
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
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* As a special exception to the terms and conditions of version 2.0 of
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* the GPL, you may redistribute this Program in connection with Free/Libre
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* and Open Source Software ("FLOSS") applications as described in Alfresco's
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* FLOSS exception. You should have recieved a copy of the text describing
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* the FLOSS exception, and it is also available here:
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* http://www.alfresco.com/legal/licensing"
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*/
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package org.alfresco.repo.lock;
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import org.alfresco.service.namespace.QName;
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/**
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* Service interface for managing job locks.
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* <p>
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* Locks are identified by a fully qualified name ({@link QName}) and follow a hierarchical
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* naming convention i.e. locks higher up a hierarchy can be shared but will prevent explicit
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* (exclusive) locks from being taken. For example: If exclusive lock <b>a.a.a</b> has been
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* taken, then <b>a.a</b> and <b>a</b> are all implicitly taken as shared locks. Exclusive lock
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* <b>a.a.b</b> can be taken by another process and will share locks <b>a.a</b> and <b>a</b>
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* with the first process. It will not be possible for a third process to take a lock on
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* <b>a.a</b>, however.
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* <p>
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* <b><u>LOCK ORDERING</u>:</b><br>
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* The transactional locks will be applied in strict alphabetical order. A very basic deadlock
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* prevention system (at least) must be in place when applying or reapplying locks and be biased
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* against locks applied non-alphabetically.
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*
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* @author Derek Hulley
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* @since 3.2
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*/
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public interface JobLockService
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{
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/**
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* Take a transactionally-managed lock. This method can be called repeatedly to both
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* initially acquire the lock as well as to maintain the lock. This method should
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* either be called again before the lock expires or the transaction should end before
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* the lock expires.
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* <p>
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* The following rules apply to taking and releasing locks:<br>
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* - Expired locks can be taken by any process<br>
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* - Lock expiration does not prevent a lock from being refreshed or released<br>
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* - Only locks that were manipulated using another token will cause failure
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* <p>
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* The locks are automatically released when the transaction is terminated.
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* <p>
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* Any failure to acquire the lock (after retries), refresh the lock or subsequently
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* release the owned locks will invalidate the transaction and cause rollback.
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*
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* @param lockQName the name of the lock to acquire
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* @param timeToLive the time (in milliseconds) for the lock to remain valid
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* @throws LockAcquisitionException if the lock could not be acquired
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* @throws IllegalStateException if a transaction is not active
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*/
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void getTransacionalLock(QName lockQName, long timeToLive);
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/**
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* {@inheritDoc JobLockService#getTransacionalLock(QName, long)}
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* <p>
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* If the lock cannot be immediately acquired, the process will wait and retry. Note
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* that second and subsequent attempts to get the lock during a transaction cannot
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* make use of retrying; the lock is actually being refreshed and will therefore never
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* become valid if it doesn't refresh directly.
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*
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* @param retryWait the time (in milliseconds) to wait before trying again
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* @param retryCount the maximum number of times to attempt the lock acquisition
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* @throws LockAcquisitionException if the lock could not be acquired
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* @throws IllegalStateException if a transaction is not active
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*/
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void getTransacionalLock(QName lockQName, long timeToLive, long retryWait, int retryCount);
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}
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