mirror of
https://github.com/Alfresco/alfresco-community-repo.git
synced 2025-08-07 17:49:17 +00:00
JobLockService implementation
- 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
This commit is contained in:
Derek Hulley
394
source/java/org/alfresco/repo/lock/JobLockServiceImpl.java
Normal file
394
source/java/org/alfresco/repo/lock/JobLockServiceImpl.java
Normal file
@@ -0,0 +1,394 @@
|
||||
/*
|
||||
* Copyright (C) 2005-2009 Alfresco Software Limited.
|
||||
*
|
||||
* This program is free software; you can redistribute it and/or
|
||||
* modify it under the terms of the GNU General Public License
|
||||
* as published by the Free Software Foundation; either version 2
|
||||
* of the License, or (at your option) any later version.
|
||||
|
||||
* This program is distributed in the hope that it will be useful,
|
||||
* but WITHOUT ANY WARRANTY; without even the implied warranty of
|
||||
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
|
||||
* GNU General Public License for more details.
|
||||
|
||||
* You should have received a copy of the GNU General Public License
|
||||
* along with this program; if not, write to the Free Software
|
||||
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
|
||||
|
||||
* As a special exception to the terms and conditions of version 2.0 of
|
||||
* the GPL, you may redistribute this Program in connection with Free/Libre
|
||||
* and Open Source Software ("FLOSS") applications as described in Alfresco's
|
||||
* FLOSS exception. You should have recieved a copy of the text describing
|
||||
* the FLOSS exception, and it is also available here:
|
||||
* http://www.alfresco.com/legal/licensing"
|
||||
*/
|
||||
package org.alfresco.repo.lock;
|
||||
|
||||
import java.util.TreeSet;
|
||||
|
||||
import org.alfresco.repo.domain.locks.LockDAO;
|
||||
import org.alfresco.repo.transaction.AlfrescoTransactionSupport;
|
||||
import org.alfresco.repo.transaction.RetryingTransactionHelper;
|
||||
import org.alfresco.repo.transaction.TransactionListenerAdapter;
|
||||
import org.alfresco.repo.transaction.TransactionalResourceHelper;
|
||||
import org.alfresco.repo.transaction.RetryingTransactionHelper.RetryingTransactionCallback;
|
||||
import org.alfresco.service.namespace.QName;
|
||||
import org.apache.commons.logging.Log;
|
||||
import org.apache.commons.logging.LogFactory;
|
||||
|
||||
/**
|
||||
* {@inheritDoc JobLockService}
|
||||
*
|
||||
* @author Derek Hulley
|
||||
* @since 3.2
|
||||
*/
|
||||
public class JobLockServiceImpl implements JobLockService
|
||||
{
|
||||
private static final String KEY_RESOURCE_LOCKS = "JobLockServiceImpl.Locks";
|
||||
|
||||
private static Log logger = LogFactory.getLog(JobLockServiceImpl.class);
|
||||
|
||||
private LockDAO lockDAO;
|
||||
private RetryingTransactionHelper retryingTransactionHelper;
|
||||
private int defaultRetryCount;
|
||||
private long defaultRetryWait;
|
||||
|
||||
/**
|
||||
* Stateless listener that does post-transaction cleanup.
|
||||
*/
|
||||
private final LockTransactionListener txnListener;
|
||||
|
||||
public JobLockServiceImpl()
|
||||
{
|
||||
defaultRetryWait = 20;
|
||||
defaultRetryCount = 10;
|
||||
txnListener = new LockTransactionListener();
|
||||
}
|
||||
|
||||
/**
|
||||
* Set the lock DAO
|
||||
*/
|
||||
public void setLockDAO(LockDAO lockDAO)
|
||||
{
|
||||
this.lockDAO = lockDAO;
|
||||
}
|
||||
|
||||
/**
|
||||
* Set the helper that will handle low-level concurrency conditions i.e. that
|
||||
* enforces optimistic locking and deals with stale state issues.
|
||||
*/
|
||||
public void setRetryingTransactionHelper(RetryingTransactionHelper retryingTransactionHelper)
|
||||
{
|
||||
this.retryingTransactionHelper = retryingTransactionHelper;
|
||||
}
|
||||
|
||||
/**
|
||||
* Set the maximum number of attempts to make at getting a lock
|
||||
* @param defaultRetryCount the number of attempts
|
||||
*/
|
||||
public void setDefaultRetryCount(int defaultRetryCount)
|
||||
{
|
||||
this.defaultRetryCount = defaultRetryCount;
|
||||
}
|
||||
|
||||
/**
|
||||
* Set the default time to wait between attempts to acquire a lock
|
||||
* @param defaultRetryWait the wait time in milliseconds
|
||||
*/
|
||||
public void setDefaultRetryWait(long defaultRetryWait)
|
||||
{
|
||||
this.defaultRetryWait = defaultRetryWait;
|
||||
}
|
||||
|
||||
/**
|
||||
* {@inheritDoc}
|
||||
*/
|
||||
public void getTransacionalLock(QName lockQName, long timeToLive)
|
||||
{
|
||||
getTransacionalLock(lockQName, timeToLive, defaultRetryWait, defaultRetryCount);
|
||||
}
|
||||
|
||||
/**
|
||||
* {@inheritDoc}
|
||||
*/
|
||||
public void getTransacionalLock(QName lockQName, long timeToLive, long retryWait, int retryCount)
|
||||
{
|
||||
// Check that transaction is present
|
||||
final String txnId = AlfrescoTransactionSupport.getTransactionId();
|
||||
if (txnId == null)
|
||||
{
|
||||
throw new IllegalStateException("Locking requires an active transaction");
|
||||
}
|
||||
// Get the set of currently-held locks
|
||||
TreeSet<QName> heldLocks = TransactionalResourceHelper.getTreeSet(KEY_RESOURCE_LOCKS);
|
||||
// We don't want the lock registered as being held if something goes wrong
|
||||
TreeSet<QName> heldLocksTemp = new TreeSet<QName>(heldLocks);
|
||||
boolean added = heldLocksTemp.add(lockQName);
|
||||
if (!added)
|
||||
{
|
||||
// It's a refresh. Ordering is not important here as we already hold the lock.
|
||||
refreshLock(lockQName, timeToLive);
|
||||
}
|
||||
else
|
||||
{
|
||||
QName lastLock = heldLocksTemp.last();
|
||||
if (lastLock.equals(lockQName))
|
||||
{
|
||||
if (logger.isDebugEnabled())
|
||||
{
|
||||
logger.debug(
|
||||
"Attempting to acquire ordered lock: \n" +
|
||||
" Lock: " + lockQName + "\n" +
|
||||
" TTL: " + timeToLive + "\n" +
|
||||
" Txn: " + txnId);
|
||||
}
|
||||
// If it was last in the set, then the order is correct and we use the
|
||||
// full retry behaviour.
|
||||
getLock(lockQName, timeToLive, retryWait, retryCount);
|
||||
}
|
||||
else
|
||||
{
|
||||
if (logger.isDebugEnabled())
|
||||
{
|
||||
logger.debug(
|
||||
"Attempting to acquire UNORDERED lock: \n" +
|
||||
" Lock: " + lockQName + "\n" +
|
||||
" TTL: " + timeToLive + "\n" +
|
||||
" Txn: " + txnId);
|
||||
}
|
||||
// The lock request is made out of natural order.
|
||||
// Unordered locks do not get any retry behaviour
|
||||
getLock(lockQName, timeToLive, retryWait, 1);
|
||||
}
|
||||
}
|
||||
// It went in, so add it to the transactionally-stored set
|
||||
heldLocks.add(lockQName);
|
||||
// Done
|
||||
}
|
||||
|
||||
/**
|
||||
* @throws LockAcquisitionException on failure
|
||||
*/
|
||||
private void refreshLock(final QName lockQName, final long timeToLive)
|
||||
{
|
||||
// The lock token is the current transaction ID
|
||||
final String txnId = AlfrescoTransactionSupport.getTransactionId();
|
||||
RetryingTransactionCallback<Object> refreshLockCallback = new RetryingTransactionCallback<Object>()
|
||||
{
|
||||
public Object execute() throws Throwable
|
||||
{
|
||||
lockDAO.releaseLock(lockQName, txnId);
|
||||
return null;
|
||||
}
|
||||
};
|
||||
try
|
||||
{
|
||||
// It must succeed
|
||||
retryingTransactionHelper.doInTransaction(refreshLockCallback, false, true);
|
||||
// Success
|
||||
if (logger.isDebugEnabled())
|
||||
{
|
||||
logger.debug(
|
||||
"Refreshed Lock: \n" +
|
||||
" Lock: " + lockQName + "\n" +
|
||||
" TTL: " + timeToLive + "\n" +
|
||||
" Txn: " + txnId);
|
||||
}
|
||||
}
|
||||
catch (LockAcquisitionException e)
|
||||
{
|
||||
// Failure
|
||||
if (logger.isDebugEnabled())
|
||||
{
|
||||
logger.debug(
|
||||
"Lock refresh failed: \n" +
|
||||
" Lock: " + lockQName + "\n" +
|
||||
" TTL: " + timeToLive + "\n" +
|
||||
" Txn: " + txnId + "\n" +
|
||||
" Error: " + e.getMessage());
|
||||
}
|
||||
throw e;
|
||||
}
|
||||
}
|
||||
|
||||
/**
|
||||
* @throws LockAcquisitionException on failure
|
||||
*/
|
||||
private void getLock(final QName lockQName, final long timeToLive, long retryWait, int retryCount)
|
||||
{
|
||||
// The lock token is the current transaction ID
|
||||
final String txnId = AlfrescoTransactionSupport.getTransactionId();
|
||||
RetryingTransactionCallback<Object> getLockCallback = new RetryingTransactionCallback<Object>()
|
||||
{
|
||||
public Object execute() throws Throwable
|
||||
{
|
||||
lockDAO.getLock(lockQName, txnId, timeToLive);
|
||||
return null;
|
||||
}
|
||||
};
|
||||
try
|
||||
{
|
||||
int iterations = doWithRetry(getLockCallback, retryWait, retryCount);
|
||||
// Bind in a listener
|
||||
AlfrescoTransactionSupport.bindListener(txnListener);
|
||||
// Success
|
||||
if (logger.isDebugEnabled())
|
||||
{
|
||||
logger.debug(
|
||||
"Acquired Lock: \n" +
|
||||
" Lock: " + lockQName + "\n" +
|
||||
" TTL: " + timeToLive + "\n" +
|
||||
" Txn: " + txnId + "\n" +
|
||||
" Attempts: " + iterations);
|
||||
}
|
||||
}
|
||||
catch (LockAcquisitionException e)
|
||||
{
|
||||
// Failure
|
||||
if (logger.isDebugEnabled())
|
||||
{
|
||||
logger.debug(
|
||||
"Lock acquisition failed: \n" +
|
||||
" Lock: " + lockQName + "\n" +
|
||||
" TTL: " + timeToLive + "\n" +
|
||||
" Txn: " + txnId + "\n" +
|
||||
" Error: " + e.getMessage());
|
||||
}
|
||||
throw e;
|
||||
}
|
||||
}
|
||||
|
||||
/**
|
||||
* Does the high-level retrying around the callback
|
||||
*/
|
||||
private int doWithRetry(RetryingTransactionCallback<? extends Object> callback, long retryWait, int retryCount)
|
||||
{
|
||||
int iteration = 0;
|
||||
LockAcquisitionException lastException = null;
|
||||
while (iteration++ < retryCount)
|
||||
{
|
||||
try
|
||||
{
|
||||
retryingTransactionHelper.doInTransaction(callback, false, true);
|
||||
// Success. Clear the exception indicator!
|
||||
lastException = null;
|
||||
break;
|
||||
}
|
||||
catch (LockAcquisitionException e)
|
||||
{
|
||||
if (logger.isDebugEnabled())
|
||||
{
|
||||
logger.debug("Lock attempt " + iteration + " of " + retryCount + " failed: " + e.getMessage());
|
||||
}
|
||||
lastException = e;
|
||||
if (iteration >= retryCount)
|
||||
{
|
||||
// Avoid an unnecessary wait if this is the last attempt
|
||||
break;
|
||||
}
|
||||
}
|
||||
// Before running again, do a wait
|
||||
synchronized(callback)
|
||||
{
|
||||
try { callback.wait(retryWait); } catch (InterruptedException e) {}
|
||||
}
|
||||
}
|
||||
if (lastException == null)
|
||||
{
|
||||
// Success
|
||||
return iteration;
|
||||
}
|
||||
else
|
||||
{
|
||||
// Failure
|
||||
throw lastException;
|
||||
}
|
||||
}
|
||||
|
||||
/**
|
||||
* Handles the transction synchronization activity, ensuring locks are rolled back as
|
||||
* required.
|
||||
*
|
||||
* @author Derek Hulley
|
||||
* @since 3.2
|
||||
*/
|
||||
private class LockTransactionListener extends TransactionListenerAdapter
|
||||
{
|
||||
/**
|
||||
* Release any open locks with extreme prejudice i.e. the commit will fail if the
|
||||
* locks cannot be released. The locks are released in a single transaction -
|
||||
* ordering is therefore not important. Should this fail, the post-commit phase
|
||||
* will do a final cleanup with individual locks.
|
||||
*/
|
||||
@Override
|
||||
public void beforeCommit(boolean readOnly)
|
||||
{
|
||||
final String txnId = AlfrescoTransactionSupport.getTransactionId();
|
||||
final TreeSet<QName> heldLocks = TransactionalResourceHelper.getTreeSet(KEY_RESOURCE_LOCKS);
|
||||
// Shortcut if there are no locks
|
||||
if (heldLocks.size() == 0)
|
||||
{
|
||||
return;
|
||||
}
|
||||
// Clean up the locks
|
||||
RetryingTransactionCallback<Object> releaseCallback = new RetryingTransactionCallback<Object>()
|
||||
{
|
||||
public Object execute() throws Throwable
|
||||
{
|
||||
// Any one of the them could fail
|
||||
for (QName lockQName : heldLocks)
|
||||
{
|
||||
lockDAO.releaseLock(lockQName, txnId);
|
||||
}
|
||||
return null;
|
||||
}
|
||||
};
|
||||
retryingTransactionHelper.doInTransaction(releaseCallback, false, true);
|
||||
// So they were all successful
|
||||
heldLocks.clear();
|
||||
}
|
||||
|
||||
/**
|
||||
* This will be called if something went wrong. It might have been the lock releases, but
|
||||
* it could be anything else as well. Each remaining lock is released with warnings where
|
||||
* it fails.
|
||||
*/
|
||||
@Override
|
||||
public void afterRollback()
|
||||
{
|
||||
final String txnId = AlfrescoTransactionSupport.getTransactionId();
|
||||
final TreeSet<QName> heldLocks = TransactionalResourceHelper.getTreeSet(KEY_RESOURCE_LOCKS);
|
||||
// Shortcut if there are no locks
|
||||
if (heldLocks.size() == 0)
|
||||
{
|
||||
return;
|
||||
}
|
||||
// Clean up any remaining locks
|
||||
for (final QName lockQName : heldLocks)
|
||||
{
|
||||
RetryingTransactionCallback<Object> releaseCallback = new RetryingTransactionCallback<Object>()
|
||||
{
|
||||
public Object execute() throws Throwable
|
||||
{
|
||||
lockDAO.releaseLock(lockQName, txnId);
|
||||
return null;
|
||||
}
|
||||
};
|
||||
try
|
||||
{
|
||||
retryingTransactionHelper.doInTransaction(releaseCallback, false, true);
|
||||
}
|
||||
catch (Throwable e)
|
||||
{
|
||||
// There is no point propagating this, so just log a warning and
|
||||
// hope that it expires soon enough
|
||||
logger.warn(
|
||||
"Failed to release a lock in 'afterRollback':\n" +
|
||||
" Lock Name: " + lockQName + "\n" +
|
||||
" Lock Token: " + txnId,
|
||||
e);
|
||||
}
|
||||
}
|
||||
}
|
||||
}
|
||||
}
|
||||
Reference in New Issue
Block a user