001/*
002 * The contents of this file are subject to the terms of the Common Development and
003 * Distribution License (the License). You may not use this file except in compliance with the
004 * License.
005 *
006 * You can obtain a copy of the License at legal/CDDLv1.0.txt. See the License for the
007 * specific language governing permission and limitations under the License.
008 *
009 * When distributing Covered Software, include this CDDL Header Notice in each file and include
010 * the License file at legal/CDDLv1.0.txt. If applicable, add the following below the CDDL
011 * Header, with the fields enclosed by brackets [] replaced by your own identifying
012 * information: "Portions Copyright [year] [name of copyright owner]".
013 *
014 * Copyright 2009-2010 Sun Microsystems, Inc.
015 * Portions copyright 2012-2016 ForgeRock AS.
016 */
017
018package org.forgerock.opendj.ldif;
019
020import java.io.Closeable;
021import java.io.IOException;
022import java.util.NoSuchElementException;
023
024/**
025 * An interface for reading change records from a data source, typically an LDIF
026 * file.
027 * <p>
028 * Implementations must specify the following:
029 * <ul>
030 * <li>Whether it is possible for the implementation to encounter
031 * malformed change records and, if it is possible, how they are handled.
032 * <li>Any synchronization limitations.
033 * </ul>
034 */
035public interface ChangeRecordReader extends Closeable {
036
037    /**
038     * Closes this change record reader if it not already closed. Note that this
039     * method does not need to be called if a previous call of
040     * {@link #readChangeRecord()} has returned {@code null}.
041     *
042     * @throws IOException
043     *             If an unexpected IO error occurred while closing.
044     */
045    @Override
046    void close() throws IOException;
047
048    /**
049     * Returns {@code true} if this reader contains another change record,
050     * blocking if necessary until either the next change record is available or
051     * the end of the stream is reached.
052     *
053     * @return {@code true} if this reader contains another change record.
054     * @throws IOException
055     *             If an unexpected IO error occurred.
056     */
057    boolean hasNext() throws IOException;
058
059    /**
060     * Reads the next change record, blocking if necessary until a change record
061     * is available. If the next change record does not contain a change type
062     * then it will be treated as an {@code Add} change record.
063     *
064     * @return The next change record.
065     * @throws IOException
066     *             If an unexpected IO error occurred while reading the change
067     *             record.
068     * @throws NoSuchElementException
069     *             If this reader does not contain any more change records.
070     */
071    ChangeRecord readChangeRecord() throws IOException;
072}