/*
|
* 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 legal-notices/CDDLv1_0.txt
|
* or http://forgerock.org/license/CDDLv1.0.html.
|
* 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 legal-notices/CDDLv1_0.txt.
|
* 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 2014 ForgeRock AS.
|
*/
|
package org.opends.server.replication.server.changelog.file;
|
|
import org.opends.server.replication.common.CSN;
|
import org.opends.server.replication.protocol.UpdateMsg;
|
import org.opends.server.replication.server.changelog.api.ChangelogException;
|
import org.opends.server.replication.server.changelog.api.DBCursor;
|
import org.opends.server.replication.server.changelog.file.Log.RepositionableCursor;
|
|
/**
|
* A cursor on ReplicaDB.
|
* <p>
|
* This cursor behaves specially in two ways :
|
* <ul>
|
* <li>The cursor initially points to a {@code null} value: the
|
* {@code getRecord()} method return {@code null} if called before any call to
|
* {@code next()} method.</li>
|
* <li>The cursor automatically re-initializes itself if it is exhausted: when
|
* exhausted, the cursor re-position itself to the last non null CSN previously
|
* read.
|
* <li>
|
* </ul>
|
*/
|
class FileReplicaDBCursor implements DBCursor<UpdateMsg>
|
{
|
|
/** The underlying cursor. */
|
private final RepositionableCursor<CSN, UpdateMsg> cursor;
|
|
/** The next record to return. */
|
private Record<CSN, UpdateMsg> nextRecord;
|
|
/** The CSN to re-start with in case the cursor is exhausted. */
|
private CSN lastNonNullCurrentCSN;
|
|
/**
|
* Creates the cursor from provided log cursor and start CSN.
|
*
|
* @param cursor
|
* The underlying log cursor to read log.
|
* @param startAfterCSN
|
* The CSN to use as a start point (excluded from cursor, the lowest
|
* CSN higher than this CSN is used as the real start point).
|
*/
|
FileReplicaDBCursor(RepositionableCursor<CSN, UpdateMsg> cursor, CSN startAfterCSN) {
|
this.cursor = cursor;
|
this.lastNonNullCurrentCSN = startAfterCSN;
|
}
|
|
/** {@inheritDoc} */
|
@Override
|
public UpdateMsg getRecord()
|
{
|
return nextRecord == null ? null : nextRecord.getValue();
|
}
|
|
/** {@inheritDoc} */
|
@Override
|
public boolean next() throws ChangelogException
|
{
|
nextRecord = cursor.getRecord();
|
if (nextRecord != null)
|
{
|
lastNonNullCurrentCSN = nextRecord.getKey();
|
}
|
else
|
{
|
// Exhausted cursor must be able to reinitialize itself
|
cursor.positionTo(lastNonNullCurrentCSN, true);
|
|
nextRecord = cursor.getRecord();
|
if (nextRecord != null)
|
{
|
lastNonNullCurrentCSN = nextRecord.getKey();
|
}
|
}
|
// the underlying cursor is one record in advance
|
cursor.next();
|
return nextRecord != null;
|
}
|
|
/** {@inheritDoc} */
|
@Override
|
public void close()
|
{
|
cursor.close();
|
}
|
|
}
|
