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 */ 017package org.apache.activemq.transport.mqtt; 018 019import java.io.DataInput; 020import java.io.DataInputStream; 021import java.io.DataOutput; 022import java.io.DataOutputStream; 023import java.io.IOException; 024 025import org.apache.activemq.util.ByteArrayInputStream; 026import org.apache.activemq.util.ByteArrayOutputStream; 027import org.apache.activemq.util.ByteSequence; 028import org.apache.activemq.wireformat.WireFormat; 029import org.fusesource.hawtbuf.Buffer; 030import org.fusesource.mqtt.codec.MQTTFrame; 031 032/** 033 * Implements marshalling and unmarsalling the <a 034 * href="http://mqtt.org/">MQTT</a> protocol. 035 */ 036public class MQTTWireFormat implements WireFormat { 037 038 static final int MAX_MESSAGE_LENGTH = 1024 * 1024 * 256; 039 static final long DEFAULT_CONNECTION_TIMEOUT = 30000L; 040 041 private int version = 1; 042 043 private int maxFrameSize = MAX_MESSAGE_LENGTH; 044 045 @Override 046 public ByteSequence marshal(Object command) throws IOException { 047 ByteArrayOutputStream baos = new ByteArrayOutputStream(); 048 DataOutputStream dos = new DataOutputStream(baos); 049 marshal(command, dos); 050 dos.close(); 051 return baos.toByteSequence(); 052 } 053 054 @Override 055 public Object unmarshal(ByteSequence packet) throws IOException { 056 ByteArrayInputStream stream = new ByteArrayInputStream(packet); 057 DataInputStream dis = new DataInputStream(stream); 058 return unmarshal(dis); 059 } 060 061 @Override 062 public void marshal(Object command, DataOutput dataOut) throws IOException { 063 MQTTFrame frame = (MQTTFrame) command; 064 dataOut.write(frame.header()); 065 066 int remaining = 0; 067 for (Buffer buffer : frame.buffers) { 068 remaining += buffer.length; 069 } 070 do { 071 byte digit = (byte) (remaining & 0x7F); 072 remaining >>>= 7; 073 if (remaining > 0) { 074 digit |= 0x80; 075 } 076 dataOut.write(digit); 077 } while (remaining > 0); 078 for (Buffer buffer : frame.buffers) { 079 dataOut.write(buffer.data, buffer.offset, buffer.length); 080 } 081 } 082 083 @Override 084 public Object unmarshal(DataInput dataIn) throws IOException { 085 byte header = dataIn.readByte(); 086 087 byte digit; 088 int multiplier = 1; 089 int length = 0; 090 do { 091 digit = dataIn.readByte(); 092 length += (digit & 0x7F) * multiplier; 093 multiplier <<= 7; 094 } 095 while ((digit & 0x80) != 0); 096 097 if (length >= 0) { 098 if (length > getMaxFrameSize()) { 099 throw new IOException("The maximum message length was exceeded"); 100 } 101 102 if (length > 0) { 103 byte[] data = new byte[length]; 104 dataIn.readFully(data); 105 Buffer body = new Buffer(data); 106 return new MQTTFrame(body).header(header); 107 } else { 108 return new MQTTFrame().header(header); 109 } 110 } 111 return null; 112 } 113 114 /** 115 * @param the version of the wire format 116 */ 117 @Override 118 public void setVersion(int version) { 119 this.version = version; 120 } 121 122 /** 123 * @return the version of the wire format 124 */ 125 @Override 126 public int getVersion() { 127 return this.version; 128 } 129 130 /** 131 * @return the maximum number of bytes a single MQTT message frame is allowed to be. 132 */ 133 public int getMaxFrameSize() { 134 return maxFrameSize; 135 } 136 137 /** 138 * Sets the maximum frame size for an incoming MQTT frame. The protocl limit is 139 * 256 megabytes and this value cannot be set higher. 140 * 141 * @param maxFrameSize 142 * the maximum allowed frame size for a single MQTT frame. 143 */ 144 public void setMaxFrameSize(int maxFrameSize) { 145 this.maxFrameSize = Math.min(MAX_MESSAGE_LENGTH, maxFrameSize); 146 } 147}