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 2009-2010 Sun Microsystems, Inc.
025 *      Portions copyright 2012 ForgeRock AS.
026 */
027
028package org.forgerock.opendj.ldif;
029
030import java.io.Closeable;
031import java.io.IOException;
032import java.util.NoSuchElementException;
033
034/**
035 * An interface for reading change records from a data source, typically an LDIF
036 * file.
037 * <p>
038 * Implementations must specify the following:
039 * <ul>
040 * <li>Whether or not it is possible for the implementation to encounter
041 * malformed change records and, if it is possible, how they are handled.
042 * <li>Any synchronization limitations.
043 * </ul>
044 */
045public interface ChangeRecordReader extends Closeable {
046
047    /**
048     * Closes this change record reader if it not already closed. Note that this
049     * method does not need to be called if a previous call of
050     * {@link #readChangeRecord()} has returned {@code null}.
051     *
052     * @throws IOException
053     *             If an unexpected IO error occurred while closing.
054     */
055    @Override
056    void close() throws IOException;
057
058    /**
059     * Returns {@code true} if this reader contains another change record,
060     * blocking if necessary until either the next change record is available or
061     * the end of the stream is reached.
062     *
063     * @return {@code true} if this reader contains another change record.
064     * @throws IOException
065     *             If an unexpected IO error occurred.
066     */
067    boolean hasNext() throws IOException;
068
069    /**
070     * Reads the next change record, blocking if necessary until a change record
071     * is available. If the next change record does not contain a change type
072     * then it will be treated as an {@code Add} change record.
073     *
074     * @return The next change record.
075     * @throws IOException
076     *             If an unexpected IO error occurred while reading the change
077     *             record.
078     * @throws NoSuchElementException
079     *             If this reader does not contain any more change records.
080     */
081    ChangeRecord readChangeRecord() throws IOException;
082}