/**
* Initialize the event queue.
*
* @param props A container of configuration properties.
* @exception FrameworkException Thrown if configuration is invalid.
*/
public void initialize(Map props) throws FrameworkException {
String temp = (String) props.get(LOAD_EVENT_BATCH_SIZE_PROP);
if (StringUtils.hasValue(temp)) {
maxDatabaseEventLoadSize = StringUtils.getInteger(temp);
if (Debug.isLevelEnabled(Debug.SYSTEM_CONFIG))
Debug.log(
Debug.SYSTEM_CONFIG,
"QUEUE OPERATION: Initializing: Maximum-database-event-batch-load-size is ["
+ maxDatabaseEventLoadSize
+ "] rows.");
}
}
/** Constructor. */
public DatabaseEventQueue() {
if (Debug.isLevelEnabled(Debug.OBJECT_LIFECYCLE))
Debug.log(
Debug.OBJECT_LIFECYCLE,
"QUEUE OPERATION: Creating event queue of type ["
+ StringUtils.getClassName(this)
+ "] ...");
queue = Collections.synchronizedList(new LinkedList());
}
/**
* Get a human-readable description of the event queue.
*
* @return A description of the event queue.
*/
public String describe() {
StringBuffer sb = new StringBuffer();
sb.append("Database event queue [");
sb.append(StringUtils.getClassName(this));
sb.append("], in-memory-event-count [");
sb.append(queue.size());
sb.append("], Event-load-batch-size [");
sb.append(maxDatabaseEventLoadSize);
sb.append("]");
return (sb.toString());
}
/**
* Reset any events meeting the given criteria so that they can be retried.
*
* @param criteria An event containing the event-selection criteria.
* @return The number of events reset.
* @exception FrameworkException Thrown on errors.
*/
protected static int reset(Event criteria) throws FrameworkException {
Debug.log(
Debug.MSG_STATUS, "QUEUE OPERATION: Resetting events in database for database queue ...");
if (!StringUtils.hasValue(criteria.channelName)) {
throw new FrameworkException(
"ERROR: Event channel name is a required queue search criteria.");
}
Connection dbConn = null;
PreparedStatement ps = null;
long startTime = -1;
if (Debug.isLevelEnabled(Debug.BENCHMARK)) startTime = System.currentTimeMillis();
try {
dbConn = DBConnectionPool.getInstance().acquireConnection();
if (Debug.isLevelEnabled(Debug.DB_DATA))
Debug.log(
Debug.DB_DATA, "Criteria used to reset events in database:\n" + criteria.describe());
// If no identifier was given that uniquely identifies a single event ...
if (criteria.id == 0) {
// Use last error time and error count, if available.
if (Debug.isLevelEnabled(Debug.DB_DATA))
Debug.log(Debug.DB_DATA, "\n" + LINE + "\nExecuting SQL:\n" + UPDATE_EVENT_RETRY_SQL);
ps = dbConn.prepareStatement(UPDATE_EVENT_RETRY_SQL);
ps.setString(1, criteria.channelName);
if (criteria.lastErrorTime == null) ps.setNull(2, Types.DATE);
else ps.setTimestamp(2, criteria.lastErrorTime);
if (criteria.errorCount < 1) ps.setNull(3, Types.INTEGER);
else ps.setInt(3, criteria.errorCount);
} else {
// An Id was given which should uniquely identify a single event, so we should
// skip using any other qualifying criteria, if present.
if (Debug.isLevelEnabled(Debug.DB_DATA))
Debug.log(
Debug.DB_DATA, "\n" + LINE + "\nExecuting SQL:\n" + UPDATE_EVENT_RETRY_BY_ID_SQL);
ps = dbConn.prepareStatement(UPDATE_EVENT_RETRY_BY_ID_SQL);
ps.setString(1, criteria.channelName);
ps.setInt(2, criteria.id);
}
int numRows = ps.executeUpdate();
DBConnectionPool.getInstance().commit(dbConn);
if (Debug.isLevelEnabled(Debug.DB_DATA))
Debug.log(
Debug.DB_DATA, "Committed SQL execution affected [" + numRows + "] rows.\n" + LINE);
return numRows;
} catch (SQLException sqle) {
throw new DatabaseException(
"ERROR: Could not execute SQL statement:\n" + DBInterface.getSQLErrorMessage(sqle));
} catch (Exception e) {
throw new DatabaseException("ERROR: Could not execute SQL statement:\n" + e.toString());
} finally {
releaseDatabaseResources(dbConn, ps);
if (Debug.isLevelEnabled(Debug.BENCHMARK) && (startTime > 0)) {
long stopTime = System.currentTimeMillis();
Debug.log(
Debug.BENCHMARK,
"ELAPSED TIME ["
+ (stopTime - startTime)
+ "] msec: "
+ "SQL: Time to reset event(s) in PersistentEvent database table.");
}
}
}
/**
* Load any available events from the database up to the configured maximum.
*
* @param criteria An event containing the event-selection criteria.
* @return The next available event on the queue.
* @exception FrameworkException Thrown on errors.
*/
private void loadFromDatabase(Event criteria) throws FrameworkException {
Debug.log(Debug.MSG_STATUS, "QUEUE OPERATION: Loading events from database into queue ...");
if (!StringUtils.hasValue(criteria.channelName)) {
throw new FrameworkException(
"ERROR: Event channel name is a required queue search criteria.");
}
Connection dbConn = null;
PreparedStatement ps = null;
long startTime = -1;
if (Debug.isLevelEnabled(Debug.BENCHMARK)) startTime = System.currentTimeMillis();
try {
dbConn = DBConnectionPool.getInstance().acquireConnection();
if (Debug.isLevelEnabled(Debug.DB_DATA))
Debug.log(Debug.DB_DATA, "\n" + LINE + "\nExecuting SQL:\n" + QUERY_EVENT_SQL);
if (Debug.isLevelEnabled(Debug.DB_DATA))
Debug.log(
Debug.DB_DATA, "Criteria used in query against database:\n" + criteria.describe());
ps = dbConn.prepareStatement(QUERY_EVENT_SQL);
ps.setString(1, criteria.channelName);
ResultSet rs = ps.executeQuery();
for (int counter = 0; (counter < maxDatabaseEventLoadSize) && rs.next(); counter++) {
Event event = new Event();
event.channelName = rs.getString(CHANNEL_NAME_COL);
event.id = rs.getInt(ID_COL);
event.message = DBLOBUtils.getCLOB(rs, MESSAGE_COL);
if (Debug.isLevelEnabled(Debug.MSG_LIFECYCLE))
Debug.log(Debug.MSG_LIFECYCLE, "Event contents:\n" + event.message);
event.arrivalTime = rs.getTimestamp(ARRIVAL_TIME_COL);
event.errorStatus = rs.getString(ERROR_STATUS_COL);
event.errorCount = rs.getInt(ERROR_COUNT_COL);
event.lastErrorMessage = rs.getString(LAST_ERROR_MESSAGE_COL);
event.lastErrorTime = rs.getTimestamp(LAST_ERROR_TIME_COL);
// Add item to in-memory buffer.
if (Debug.isLevelEnabled(Debug.MSG_STATUS))
Debug.log(
Debug.MSG_STATUS,
"Adding event [" + event.describe() + "] to in-memory queue buffer.");
queue.add(event);
if (Debug.isLevelEnabled(Debug.MSG_STATUS))
Debug.log(Debug.MSG_STATUS, "In-memory queue buffer size [" + queue.size() + "].");
}
if (Debug.isLevelEnabled(Debug.DB_DATA)) Debug.log(Debug.DB_DATA, "\n" + LINE);
} catch (SQLException sqle) {
throw new DatabaseException(
"ERROR: Could not execute SQL statement:\n" + DBInterface.getSQLErrorMessage(sqle));
} catch (Exception e) {
throw new DatabaseException("ERROR: Could not execute SQL statement:\n" + e.toString());
} finally {
releaseDatabaseResources(dbConn, ps);
if (Debug.isLevelEnabled(Debug.BENCHMARK) && (startTime > 0)) {
long stopTime = System.currentTimeMillis();
Debug.log(
Debug.BENCHMARK,
"ELAPSED TIME ["
+ (stopTime - startTime)
+ "] msec: "
+ "SQL: Time to load event(s) from PersistentEvent database table.");
}
}
}
