Package org.apache.activemq.transport.stomp

Source Code of org.apache.activemq.transport.stomp.StompNIOTransport

/**
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements.  See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to You under the Apache License, Version 2.0
* (the "License"); you may not use this file except in compliance with
* the License.  You may obtain a copy of the License at
*
*      http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.apache.activemq.transport.stomp;

import java.io.ByteArrayInputStream;
import java.io.DataOutputStream;
import java.io.EOFException;
import java.io.IOException;
import java.net.Socket;
import java.net.URI;
import java.net.UnknownHostException;
import java.nio.ByteBuffer;
import java.nio.channels.SelectionKey;
import java.nio.channels.SocketChannel;

import javax.net.SocketFactory;

import org.apache.activemq.command.Command;
import org.apache.activemq.transport.Transport;
import org.apache.activemq.transport.nio.NIOOutputStream;
import org.apache.activemq.transport.nio.SelectorManager;
import org.apache.activemq.transport.nio.SelectorSelection;
import org.apache.activemq.transport.tcp.TcpTransport;
import org.apache.activemq.util.ByteArrayOutputStream;
import org.apache.activemq.util.ByteSequence;
import org.apache.activemq.util.IOExceptionSupport;
import org.apache.activemq.util.ServiceStopper;
import org.apache.activemq.wireformat.WireFormat;

/**
* An implementation of the {@link Transport} interface for using Stomp over NIO
*
* @version $Revision$
*/
public class StompNIOTransport extends TcpTransport {

    private SocketChannel channel;
    private SelectorSelection selection;
   
    private ByteBuffer inputBuffer;
    ByteArrayOutputStream currentCommand = new ByteArrayOutputStream();
    int previousByte = -1;

    public StompNIOTransport(WireFormat wireFormat, SocketFactory socketFactory, URI remoteLocation, URI localLocation) throws UnknownHostException, IOException {
        super(wireFormat, socketFactory, remoteLocation, localLocation);
    }

    public StompNIOTransport(WireFormat wireFormat, Socket socket) throws IOException {
        super(wireFormat, socket);
    }

    protected void initializeStreams() throws IOException {
        channel = socket.getChannel();
        channel.configureBlocking(false);

        // listen for events telling us when the socket is readable.
        selection = SelectorManager.getInstance().register(channel, new SelectorManager.Listener() {
            public void onSelect(SelectorSelection selection) {
                serviceRead();
            }

            public void onError(SelectorSelection selection, Throwable error) {
                if (error instanceof IOException) {
                    onException((IOException)error);
                } else {
                    onException(IOExceptionSupport.create(error));
                }
            }
        });

        inputBuffer = ByteBuffer.allocate(8 * 1024);
        this.dataOut = new DataOutputStream(new NIOOutputStream(channel, 8 * 1024));
    }
   
    private void serviceRead() {
        try {
           
           while (true) {
               // read channel
               int readSize = channel.read(inputBuffer);
               // channel is closed, cleanup
               if (readSize == -1) {
                   onException(new EOFException());
                   selection.close();
                   break;
               }
               // nothing more to read, break
               if (readSize == 0) {
                   break;
               }
              
               inputBuffer.flip();
              
               int b;
               ByteArrayInputStream input = new ByteArrayInputStream(inputBuffer.array());
              
               int i = 0;
               while(i++ < readSize) {
                   b = input.read();
                   // skip repeating nulls
                   if (previousByte == 0 && b == 0) {
                       continue;
                   }
                   currentCommand.write(b);
                   // end of command reached, unmarshal
                   if (b == 0) {
                       Object command = wireFormat.unmarshal(new ByteSequence(currentCommand.toByteArray()));
                       doConsume((Command)command);
                       currentCommand.reset();
                   }
                   previousByte = b;
               }
               // clear the buffer
               inputBuffer.clear();
              
           }
        } catch (IOException e) {
            onException(e)
        } catch (Throwable e) {
            onException(IOExceptionSupport.create(e));
        }
    }

    protected void doStart() throws Exception {
        connect();
        selection.setInterestOps(SelectionKey.OP_READ);
        selection.enable();
    }

    protected void doStop(ServiceStopper stopper) throws Exception {
        try {
            selection.close();
        } catch (Exception e) {
          e.printStackTrace();
        }
        super.doStop(stopper);
    }
}
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