/*
* CDDL HEADER START
*
* The contents of this file are subject to the terms of the
* Common Development and Distribution License, Version 1.0 only
* (the "License"). You may not use this file except in compliance
* with the License.
*
* You can obtain a copy of the license at
* trunk/opends/resource/legal-notices/OpenDS.LICENSE
* or https://OpenDS.dev.java.net/OpenDS.LICENSE.
* See the License for the specific language governing permissions
* and limitations under the License.
*
* When distributing Covered Code, include this CDDL HEADER in each
* file and include the License file at
* trunk/opends/resource/legal-notices/OpenDS.LICENSE. If applicable,
* add the following below this CDDL HEADER, with the fields enclosed
* by brackets "[]" replaced with your own identifying information:
* Portions Copyright [yyyy] [name of copyright owner]
*
* CDDL HEADER END
*
*
* Copyright 2006-2009 Sun Microsystems, Inc.
* Portions Copyright 2011-2013 ForgeRock AS
*/
package org.opends.server.replication.server;
import org.opends.server.replication.common.ChangeNumber;
import org.opends.server.replication.protocol.UpdateMsg;
import org.opends.server.replication.server.ReplicationDB.ReplServerDBCursor;
import com.sleepycat.je.DatabaseException;
/**
* This class allows to iterate through the changes received from a given
* LDAP Server Identifier.
*/
public class ReplicationIterator
{
private UpdateMsg currentChange = null;
private ReplServerDBCursor cursor = null;
private DbHandler dbh;
private ReplicationDB db;
ChangeNumber lastNonNullCurrentCN;
/**
* Creates a new ReplicationIterator.
* All created iterator must be released by the caller using the
* releaseCursor() method.
*
* @param id the Identifier of the server on which the iterator applies.
* @param db The db where the iterator must be created.
* @param changeNumber The ChangeNumber after which the iterator must start.
* @param dbh The associated DbHandler.
* @throws Exception If there is no other change to push after change
* with changeNumber number.
* @throws DatabaseException if a database problem happened.
*/
public ReplicationIterator(
int id, ReplicationDB db, ChangeNumber changeNumber, DbHandler dbh)
throws Exception, DatabaseException
{
this.db = db;
this.dbh = dbh;
this.lastNonNullCurrentCN = changeNumber;
try
{
cursor = db.openReadCursor(changeNumber);
}
catch(Exception e)
{
// we didn't find it in the db
cursor = null;
}
if (cursor == null)
{
// flush the queue into the db
dbh.flush();
// look again in the db
cursor = db.openReadCursor(changeNumber);
if (cursor == null)
{
throw new Exception("no new change");
}
}
}
/**
* Get the UpdateMsg where the iterator is currently set.
* @return The UpdateMsg where the iterator is currently set.
*/
public UpdateMsg getChange()
{
return currentChange;
}
/**
* Go to the next change in the ReplicationDB or in the server Queue.
* @return false if the iterator is already on the last change before
* this call.
*/
public boolean next()
{
boolean hasNext;
currentChange = cursor.next(); // can return null
if (currentChange != null)
{
lastNonNullCurrentCN = currentChange.getChangeNumber();
hasNext = true;
}
else
{
synchronized (this)
{
if (cursor != null)
{
cursor.close();
cursor = null;
}
dbh.flush();
try
{
cursor = db.openReadCursor(lastNonNullCurrentCN);
currentChange = cursor.next();
if (currentChange != null)
{
lastNonNullCurrentCN = currentChange.getChangeNumber();
hasNext = true;
}
else
{
hasNext = false;
}
}
catch(Exception e)
{
currentChange = null;
hasNext = false;
}
}
}
return hasNext;
}
/**
* Release the resources and locks used by this Iterator.
* This method must be called when the iterator is no longer used.
* Failure to do it could cause DB deadlock.
*/
public void releaseCursor()
{
synchronized (this)
{
if (cursor != null)
{
cursor.close();
cursor = null;
}
this.dbh = null;
this.db = null;
}
}
/**
* Called by the Gc when the object is garbage collected
* Release the cursor in case the iterator was badly used and releaseCursor
* was never called.
*/
protected void finalize()
{
releaseCursor();
}
}