001 /**
002 * Licensed to the Apache Software Foundation (ASF) under one or more
003 * contributor license agreements. See the NOTICE file distributed with
004 * this work for additional information regarding copyright ownership.
005 * The ASF licenses this file to You under the Apache License, Version 2.0
006 * (the "License"); you may not use this file except in compliance with
007 * the License. You may obtain a copy of the License at
008 *
009 * http://www.apache.org/licenses/LICENSE-2.0
010 *
011 * Unless required by applicable law or agreed to in writing, software
012 * distributed under the License is distributed on an "AS IS" BASIS,
013 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
014 * See the License for the specific language governing permissions and
015 * limitations under the License.
016 */
017 package org.apache.activemq.transport.mqtt;
018
019 import java.io.DataInput;
020 import java.io.DataInputStream;
021 import java.io.DataOutput;
022 import java.io.DataOutputStream;
023 import java.io.IOException;
024
025 import org.apache.activemq.util.ByteArrayInputStream;
026 import org.apache.activemq.util.ByteArrayOutputStream;
027 import org.apache.activemq.util.ByteSequence;
028 import org.apache.activemq.wireformat.WireFormat;
029 import org.fusesource.hawtbuf.Buffer;
030 import org.fusesource.mqtt.codec.MQTTFrame;
031
032 /**
033 * Implements marshalling and unmarsalling the <a
034 * href="http://mqtt.org/">MQTT</a> protocol.
035 */
036 public class MQTTWireFormat implements WireFormat {
037
038
039 static final int MAX_MESSAGE_LENGTH = 1024 * 1024 * 256;
040
041 private boolean encodingEnabled = false;
042 private int version = 1;
043
044 public ByteSequence marshal(Object command) throws IOException {
045 ByteArrayOutputStream baos = new ByteArrayOutputStream();
046 DataOutputStream dos = new DataOutputStream(baos);
047 marshal(command, dos);
048 dos.close();
049 return baos.toByteSequence();
050 }
051
052 public Object unmarshal(ByteSequence packet) throws IOException {
053 ByteArrayInputStream stream = new ByteArrayInputStream(packet);
054 DataInputStream dis = new DataInputStream(stream);
055 return unmarshal(dis);
056 }
057
058 public void marshal(Object command, DataOutput dataOut) throws IOException {
059 MQTTFrame frame = (MQTTFrame) command;
060 dataOut.write(frame.header());
061
062 int remaining = 0;
063 for (Buffer buffer : frame.buffers) {
064 remaining += buffer.length;
065 }
066 do {
067 byte digit = (byte) (remaining & 0x7F);
068 remaining >>>= 7;
069 if (remaining > 0) {
070 digit |= 0x80;
071 }
072 dataOut.write(digit);
073 } while (remaining > 0);
074 for (Buffer buffer : frame.buffers) {
075 dataOut.write(buffer.data, buffer.offset, buffer.length);
076 }
077 }
078
079 public Object unmarshal(DataInput dataIn) throws IOException {
080 byte header = dataIn.readByte();
081
082 byte digit;
083 int multiplier = 1;
084 int length = 0;
085 do {
086 digit = dataIn.readByte();
087 length += (digit & 0x7F) * multiplier;
088 multiplier <<= 7;
089 }
090 while ((digit & 0x80) != 0);
091
092 if (length >= 0) {
093 if (length > MAX_MESSAGE_LENGTH) {
094 throw new IOException("The maximum message length was exceeded");
095 }
096
097 if (length > 0) {
098 byte[] data = new byte[length];
099 dataIn.readFully(data);
100 Buffer body = new Buffer(data);
101 return new MQTTFrame(body).header(header);
102 } else {
103 return new MQTTFrame().header(header);
104 }
105 }
106 return null;
107 }
108
109 /**
110 * @param the version of the wire format
111 */
112 public void setVersion(int version) {
113 this.version = version;
114 }
115
116 /**
117 * @return the version of the wire format
118 */
119 public int getVersion() {
120 return this.version;
121 }
122
123
124 }