001/*
002 * CDDL HEADER START
003 *
004 * The contents of this file are subject to the terms of the
005 * Common Development and Distribution License, Version 1.0 only
006 * (the "License").  You may not use this file except in compliance
007 * with the License.
008 *
009 * You can obtain a copy of the license at legal-notices/CDDLv1_0.txt
010 * or http://forgerock.org/license/CDDLv1.0.html.
011 * See the License for the specific language governing permissions
012 * and limitations under the License.
013 *
014 * When distributing Covered Code, include this CDDL HEADER in each
015 * file and include the License file at legal-notices/CDDLv1_0.txt.
016 * If applicable, add the following below this CDDL HEADER, with the
017 * fields enclosed by brackets "[]" replaced with your own identifying
018 * information:
019 *      Portions Copyright [yyyy] [name of copyright owner]
020 *
021 * CDDL HEADER END
022 *
023 *
024 *      Copyright 2009 Sun Microsystems, Inc.
025 *      Portions Copyright 2011-2015 ForgeRock AS
026 */
027package org.opends.server.replication.server.changelog.je;
028
029import org.forgerock.i18n.slf4j.LocalizedLogger;
030import org.opends.server.replication.server.changelog.api.*;
031import org.opends.server.replication.server.changelog.je.DraftCNDB.*;
032
033/**
034 * This class allows to iterate through the changes comming from the change number index DB.
035 *
036 * \@NotThreadSafe
037 */
038public class JEChangeNumberIndexDBCursor implements
039    DBCursor<ChangeNumberIndexRecord>
040{
041  private static final LocalizedLogger logger = LocalizedLogger.getLoggerForThisClass();
042  private DraftCNDBCursor draftCNDbCursor;
043
044  /**
045   * As underlying cursor is already pointing to a record at start, this
046   * indicator allow to shift the pointed record at initialization time.
047   */
048  private boolean isInitialized;
049
050  /**
051   * Creates a new DB Cursor. All created iterator must be released by
052   * the caller using the {@link #close()} method.
053   *
054   * @param db
055   *          The db where the iterator must be created.
056   * @param startChangeNumber
057   *          The change number after which the iterator must start.
058   * @throws ChangelogException
059   *           If a database problem happened.
060   */
061  public JEChangeNumberIndexDBCursor(DraftCNDB db, long startChangeNumber)
062      throws ChangelogException
063  {
064    draftCNDbCursor = db.openReadCursor(startChangeNumber);
065  }
066
067  /** {@inheritDoc} */
068  @Override
069  public ChangeNumberIndexRecord getRecord()
070  {
071    try
072    {
073      return isInitialized ? draftCNDbCursor.currentRecord() : null;
074    }
075    catch (Exception e)
076    {
077      logger.traceException(e);
078      return null;
079    }
080  }
081
082  /** {@inheritDoc} */
083  @Override
084  public boolean next() throws ChangelogException
085  {
086    if (draftCNDbCursor != null)
087    {
088      if (!isInitialized)
089      {
090        isInitialized = true;
091        return draftCNDbCursor.currentRecord() != null;
092      }
093      else
094      {
095        return draftCNDbCursor.next();
096      }
097    }
098    return false;
099  }
100
101  /** {@inheritDoc} */
102  @Override
103  public void close()
104  {
105    synchronized (this)
106    {
107      if (draftCNDbCursor != null)
108      {
109        draftCNDbCursor.close();
110        draftCNDbCursor = null;
111      }
112    }
113  }
114
115  /**
116   * Called by the Gc when the object is garbage collected
117   * Release the cursor in case the iterator was badly used and releaseCursor
118   * was never called.
119   */
120  @Override
121  protected void finalize()
122  {
123    close();
124  }
125
126}