/**
* Checks whether there's a local revision value in the database for this cluster node. If not,
* it writes the given default revision to the database.
*
* @param revision the default value for the local revision counter
* @return the local revision
* @throws JournalException on error
*/
protected synchronized long init(long revision) throws JournalException {
ResultSet rs = null;
try {
// Check whether there is an entry in the database.
rs = conHelper.exec(getLocalRevisionStmtSQL, new Object[] {getId()}, false, 0);
boolean exists = rs.next();
if (exists) {
revision = rs.getLong(1);
}
// Insert the given revision in the database
if (!exists) {
conHelper.exec(insertLocalRevisionStmtSQL, revision, getId());
}
// Set the cached local revision and return
localRevision = revision;
initialized = true;
return revision;
} catch (SQLException e) {
log.warn("Failed to initialize local revision.", e);
throw new JournalException("Failed to initialize local revision", e);
} finally {
DbUtility.close(rs);
}
}
/**
* {@inheritDoc}
*
* <p>This journal is locked by incrementing the current value in the table named <code>
* GLOBAL_REVISION</code>, which effectively write-locks this table. The updated value is then
* saved away and remembered in the appended record, because a save may entail multiple appends
* (JCR-884).
*/
protected void doLock() throws JournalException {
ResultSet rs = null;
boolean succeeded = false;
try {
startBatch();
} catch (SQLException e) {
throw new JournalException("Unable to set autocommit to false.", e);
}
try {
conHelper.exec(updateGlobalStmtSQL);
rs = conHelper.exec(selectGlobalStmtSQL, null, false, 0);
if (!rs.next()) {
throw new JournalException("No revision available.");
}
lockedRevision = rs.getLong(1);
succeeded = true;
} catch (SQLException e) {
throw new JournalException("Unable to lock global revision table.", e);
} finally {
DbUtility.close(rs);
if (!succeeded) {
doUnlock(false);
}
}
}
/** Cleans old revisions from the clustering table. */
protected void cleanUpOldRevisions() {
ResultSet rs = null;
try {
long minRevision = 0;
rs = conHelper.exec(selectMinLocalRevisionStmtSQL, null, false, 0);
boolean cleanUp = rs.next();
if (cleanUp) {
minRevision = rs.getLong(1);
}
// Clean up if necessary:
if (cleanUp) {
conHelper.exec(cleanRevisionStmtSQL, minRevision);
log.info("Cleaned old revisions up to revision " + minRevision + ".");
}
} catch (Exception e) {
log.warn("Failed to clean up old revisions.", e);
} finally {
DbUtility.close(rs);
}
}