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 */
020
021 package org.apache.directory.server.ntp.io;
022
023
024 import java.nio.ByteBuffer;
025
026 import org.apache.directory.server.ntp.messages.LeapIndicatorType;
027 import org.apache.directory.server.ntp.messages.ModeType;
028 import org.apache.directory.server.ntp.messages.NtpMessage;
029 import org.apache.directory.server.ntp.messages.ReferenceIdentifier;
030
031
032 /**
033 * @author <a href="mailto:dev@directory.apache.org">Apache Directory Project</a>
034 * @version $Rev: 547539 $, $Date: 2007-06-15 09:08:06 +0300 (Fri, 15 Jun 2007) $
035 */
036 public class NtpMessageEncoder
037 {
038 /**
039 * Encodes the {@link NtpMessage} into the {@link ByteBuffer}.
040 *
041 * @param byteBuffer
042 * @param message
043 */
044 public void encode( ByteBuffer byteBuffer, NtpMessage message )
045 {
046 byte header = 0x00;
047 header = encodeLeapIndicator( message.getLeapIndicator(), header );
048 header = encodeVersionNumber( message.getVersionNumber(), header );
049 header = encodeMode( message.getMode(), header );
050 byteBuffer.put( header );
051
052 byteBuffer.put( ( byte ) ( message.getStratum().getOrdinal() & 0xFF ) );
053 byteBuffer.put( ( byte ) ( message.getPollInterval() & 0xFF ) );
054 byteBuffer.put( ( byte ) ( message.getPrecision() & 0xFF ) );
055
056 byteBuffer.putInt( message.getRootDelay() );
057 byteBuffer.putInt( message.getRootDispersion() );
058
059 encodeReferenceIdentifier( message.getReferenceIdentifier(), byteBuffer );
060
061 message.getReferenceTimestamp().writeTo( byteBuffer );
062 message.getOriginateTimestamp().writeTo( byteBuffer );
063 message.getReceiveTimestamp().writeTo( byteBuffer );
064 message.getTransmitTimestamp().writeTo( byteBuffer );
065 }
066
067
068 private byte encodeLeapIndicator( LeapIndicatorType leapIndicator, byte header )
069 {
070 byte twoBits = ( byte ) ( leapIndicator.getOrdinal() & 0x03 );
071 return ( byte ) ( ( twoBits << 6 ) | header );
072 }
073
074
075 private byte encodeVersionNumber( int versionNumber, byte header )
076 {
077 byte threeBits = ( byte ) ( versionNumber & 0x07 );
078 return ( byte ) ( ( threeBits << 3 ) | header );
079 }
080
081
082 private byte encodeMode( ModeType mode, byte header )
083 {
084 byte threeBits = ( byte ) ( mode.getOrdinal() & 0x07 );
085 return ( byte ) ( threeBits | header );
086 }
087
088
089 private void encodeReferenceIdentifier( ReferenceIdentifier identifier, ByteBuffer byteBuffer )
090 {
091 char[] characters = identifier.getCode().toCharArray();
092
093 for ( int ii = 0; ii < characters.length; ii++ )
094 {
095 byteBuffer.put( ( byte ) characters[ii] );
096 }
097 }
098 }