001/*
002 *  Licensed to the Apache Software Foundation (ASF) under one
003 *  or more contributor license agreements.  See the NOTICE file
004 *  distributed with this work for additional information
005 *  regarding copyright ownership.  The ASF licenses this file
006 *  to you under the Apache License, Version 2.0 (the
007 *  "License"); you may not use this file except in compliance
008 *  with the License.  You may obtain a copy of the License at
009 *  
010 *    http://www.apache.org/licenses/LICENSE-2.0
011 *  
012 *  Unless required by applicable law or agreed to in writing,
013 *  software distributed under the License is distributed on an
014 *  "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
015 *  KIND, either express or implied.  See the License for the
016 *  specific language governing permissions and limitations
017 *  under the License. 
018 *  
019 */
020package org.apache.directory.server.kerberos.changepwd.io;
021
022
023import java.nio.ByteBuffer;
024import java.nio.InvalidMarkException;
025
026import org.apache.directory.server.kerberos.changepwd.exceptions.ChangePasswordException;
027import org.apache.directory.server.kerberos.changepwd.messages.AbstractPasswordMessage;
028import org.apache.directory.server.kerberos.changepwd.messages.ChangePasswordError;
029import org.apache.directory.server.kerberos.changepwd.messages.ChangePasswordReply;
030import org.apache.directory.server.kerberos.changepwd.messages.ChangePasswordRequest;
031
032
033/**
034 * @author <a href="mailto:dev@directory.apache.org">Apache Directory Project</a>
035 */
036public class ChangePasswordDecoder
037{
038    public static AbstractPasswordMessage decode( ByteBuffer buf, boolean isTcp ) throws ChangePasswordException
039    {
040        if ( isTcp )
041        {
042            // For TCP transport, there is a 4 octet header in network byte order
043            // that precedes the message and specifies the length of the message.
044            buf.getInt();
045            buf.mark();
046        }
047
048        // cause we don't have a special message type value, try decoding as request, reply and error and send whichever succeeds
049
050        try
051        {
052            return ChangePasswordRequest.decode( buf );
053        }
054        catch ( Exception e )
055        {
056            resetOrRewind( buf );
057        }
058
059        try
060        {
061            return ChangePasswordReply.decode( buf );
062        }
063        catch ( Exception e )
064        {
065            resetOrRewind( buf );
066        }
067
068        return ChangePasswordError.decode( buf );
069    }
070
071
072    private static void resetOrRewind( ByteBuffer buf )
073    {
074        try
075        {
076            buf.reset();
077        }
078        catch ( InvalidMarkException e )
079        {
080            buf.rewind();
081        }
082    }
083}