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.DataOutputStream;
020import java.io.EOFException;
021import java.io.IOException;
022import java.net.Socket;
023import java.net.URI;
024import java.net.UnknownHostException;
025import java.nio.ByteBuffer;
026import java.nio.channels.SelectionKey;
027import java.nio.channels.SocketChannel;
028
029import javax.net.SocketFactory;
030
031import org.apache.activemq.transport.nio.NIOOutputStream;
032import org.apache.activemq.transport.nio.SelectorManager;
033import org.apache.activemq.transport.nio.SelectorSelection;
034import org.apache.activemq.transport.tcp.TcpTransport;
035import org.apache.activemq.util.IOExceptionSupport;
036import org.apache.activemq.util.ServiceStopper;
037import org.apache.activemq.wireformat.WireFormat;
038import org.fusesource.hawtbuf.DataByteArrayInputStream;
039
040/**
041 * An implementation of the {@link org.apache.activemq.transport.Transport} interface for using MQTT over NIO
042 */
043public class MQTTNIOTransport extends TcpTransport {
044
045    private SocketChannel channel;
046    private SelectorSelection selection;
047
048    private ByteBuffer inputBuffer;
049    MQTTCodec codec;
050
051    public MQTTNIOTransport(WireFormat wireFormat, SocketFactory socketFactory, URI remoteLocation, URI localLocation) throws UnknownHostException, IOException {
052        super(wireFormat, socketFactory, remoteLocation, localLocation);
053    }
054
055    public MQTTNIOTransport(WireFormat wireFormat, Socket socket) throws IOException {
056        super(wireFormat, socket);
057    }
058
059    @Override
060    protected void initializeStreams() throws IOException {
061        channel = socket.getChannel();
062        channel.configureBlocking(false);
063        // listen for events telling us when the socket is readable.
064        selection = SelectorManager.getInstance().register(channel, new SelectorManager.Listener() {
065            @Override
066            public void onSelect(SelectorSelection selection) {
067                if (!isStopped()) {
068                    serviceRead();
069                }
070            }
071
072            @Override
073            public void onError(SelectorSelection selection, Throwable error) {
074                if (error instanceof IOException) {
075                    onException((IOException) error);
076                } else {
077                    onException(IOExceptionSupport.create(error));
078                }
079            }
080        });
081
082        inputBuffer = ByteBuffer.allocate(8 * 1024);
083        NIOOutputStream outPutStream = new NIOOutputStream(channel, 8 * 1024);
084        dataOut = new DataOutputStream(outPutStream);
085        buffOut = outPutStream;
086        codec = new MQTTCodec(this, (MQTTWireFormat) getWireFormat());
087    }
088
089    private void serviceRead() {
090        try {
091
092            while (isStarted()) {
093                // read channel
094                int readSize = channel.read(inputBuffer);
095                // channel is closed, cleanup
096                if (readSize == -1) {
097                    onException(new EOFException());
098                    selection.close();
099                    break;
100                }
101                // nothing more to read, break
102                if (readSize == 0) {
103                    break;
104                }
105
106                inputBuffer.flip();
107                DataByteArrayInputStream dis = new DataByteArrayInputStream(inputBuffer.array());
108                codec.parse(dis, readSize);
109
110                receiveCounter += readSize;
111
112                // clear the buffer
113                inputBuffer.clear();
114            }
115        } catch (IOException e) {
116            onException(e);
117        } catch (Throwable e) {
118            onException(IOExceptionSupport.create(e));
119        }
120    }
121
122    @Override
123    protected void doStart() throws Exception {
124        connect();
125        selection.setInterestOps(SelectionKey.OP_READ);
126        selection.enable();
127    }
128
129    @Override
130    protected void doStop(ServiceStopper stopper) throws Exception {
131        try {
132            if (selection != null) {
133                selection.close();
134            }
135        } finally {
136            super.doStop(stopper);
137        }
138    }
139}