Android Open Source - ubihelper Socket Channel Websocket

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License

The source code is released under:

GNU General Public License

Java Source Code

/**
 * Copyright (c) 2012 The University of Nottingham
 * /*from w  ww  . j  a  va2  s .c om*/
 * This file is part of ubihelper
 *
 *  ubihelper is free software: you can redistribute it and/or modify
 *  it under the terms of the GNU Affero General Public License as published by
 *  the Free Software Foundation, either version 3 of the License, or
 *  (at your option) any later version.
 *
 *  ubihelper is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU Affero General Public License for more details.
 *
 *  You should have received a copy of the GNU Affero General Public License
 *  along with ubihelper. If not, see <http://www.gnu.org/licenses/>.
 *  
 *  @author Chris Greenhalgh (cmg@cs.nott.ac.uk), The University of Nottingham
 */
package uk.ac.horizon.ubihelper.websocket;

import java.io.IOException;
import java.net.InetAddress;
import java.net.InetSocketAddress;
import java.nio.ByteBuffer;
import java.nio.channels.ClosedChannelException;
import java.nio.channels.SelectionKey;
import java.nio.channels.Selector;
import java.nio.channels.ServerSocketChannel;
import java.nio.channels.SocketChannel;
import java.util.LinkedList;
import java.util.List;
import java.util.concurrent.locks.ReentrantLock;
import java.util.logging.Level;
import java.util.logging.Logger;

/**
 * Common stuff for Websocket (after handshake) over SocketChannel, i.e. selectable 
 * and non-blocking.
 * 
 * @author cmg
 *
 */
public class SocketChannelWebsocket extends Websocket {
  private static final int DEFAULT_BUFFER_SIZE = 10000;
  static Logger logger = Logger.getLogger(SocketChannelWebsocket.class.getName());
  protected SocketChannel socketChannel;
  private Selector selector;
  private ReentrantLock selectorLock;
  private LinkedList<ByteBuffer> writeQueue = new LinkedList<ByteBuffer>();
  protected LinkedList<ByteBuffer> readQueue = new LinkedList<ByteBuffer>();
  protected ByteBuffer readBuffer = null;
  
  protected SocketChannelWebsocket(ReadyState initialState, Selector selector, ReentrantLock selectorLock, WebsocketListener listener) {
    super(initialState, listener);
    this.selector = selector;
    this.selectorLock = selectorLock;
  }
  
  /** will perform accept - call when ready */
  public SocketChannelWebsocket getWebsocket(ServerSocketChannel serverSocketChannel, Selector selector, ReentrantLock selectorLock, WebsocketListener listener) {
    // TODO
    throw new RuntimeException("unimplemented: getWebsocket(ServerSocketChannel)");
  }
  
  /** will perform connect */
  public SocketChannelWebsocket getWebsocket(String host, int port, Selector selector, ReentrantLock selectorLock, WebsocketListener listener) throws IOException {
    SocketChannelWebsocket scw = new SocketChannelWebsocket(ReadyState.CONNECTING, selector, selectorLock, listener);
    scw.connect(host, port);
    return scw;
  }
  
  protected synchronized void connect(String host, int port) throws IOException {
    try {
      readyState = ReadyState.CONNECTING;
      socketChannel = SocketChannel.open();
      // non-blocking
      socketChannel.configureBlocking(false);
      InetSocketAddress address = new InetSocketAddress(host, port);
      socketChannel.connect(address);
      register(SelectionKey.OP_CONNECT);
    }
    catch (IOException ioe) {
      logger.info("connect("+host+","+port+") failed: "+ioe);
      try {
        socketChannel.close();
      }
      catch (Exception e) { /* */ }
      socketChannel = null;
      readyState = ReadyState.CLOSED;
      // re-throwing exception, not listener
      throw ioe;
    }
  }
  protected void register(int ops) throws ClosedChannelException {
    selectorLock.lock();
    try {
      socketChannel.register(selector, ops, this);
    }
    finally {
      selectorLock.unlock();
    }
  }

  /** on selector key callback */
  public synchronized void onSelect(SelectionKey key) {
    if (key.isConnectable() && readyState==ReadyState.CONNECTING) {
      logger.info("connected");
      try {
        socketChannel.finishConnect();
        readyState = ReadyState.OPEN;
        register(SelectionKey.OP_READ);
        callOnopen();
      }
      catch (Exception e) {
        logger.log(Level.WARNING, "error handling connect", e);
        error();
        return;
      }
    }
    if (key.isWritable()) {
      while (!writeQueue.isEmpty()) {
        try {
          ByteBuffer buf = writeQueue.removeFirst();
          int cnt = socketChannel.write(buf);
          logger.info("wrote "+cnt+" bytes, "+buf.remaining()+" remaining");
          if (buf.remaining()>0) {
            // would block - put back (rest)
            writeQueue.add(0, buf);;
            break;
          }
        }
        catch (Exception e) {
          logger.log(Level.WARNING,"Error writing", e);
          error();
          return;
        }
      }
      if (writeQueue.isEmpty()) {
        // no need to select for write
        try {
          register(SelectionKey.OP_READ);
        } catch (ClosedChannelException e) {
          logger.log(Level.WARNING,"Error registering for read (after write)", e);
          error();
          return;
        }
      }
    }
    if (key.isReadable()) {
      while (true) {
        if (readBuffer!=null && readBuffer.remaining()<=0) {
          queueReadBuffer();
        }
        if (readBuffer==null) {
          readBuffer = ByteBuffer.allocate(DEFAULT_BUFFER_SIZE);
        } 
        try {
          int cnt = socketChannel.read(readBuffer);
          if (cnt<=0) {
            // done 
            logger.info("Did not read anything - open? "+socketChannel.isOpen()+", connected? "+socketChannel.isConnected()+" inputShutdown? "+socketChannel.socket().isInputShutdown()+" outputShutdown? "+socketChannel.socket().isOutputShutdown()+", position="+readBuffer.position()+", "+readBuffer.remaining()+" remaining");
            break;
          }
          logger.info("Read "+cnt+" bytes");
        } catch (IOException e) {
          logger.info("Error reading from socket: "+e);
          error();
          return;
        }
      }
      if (readQueue.isEmpty() && readBuffer.position()>0) {
        // promote new buffer
        queueReadBuffer();
      }
      if (!readQueue.isEmpty()) {
        handleReadQueue();
      }
    }
  }
  
  protected void queueReadBuffer() {
    readBuffer.limit(readBuffer.position());
    readBuffer.position(0);
    readQueue.add(readBuffer);
    readBuffer = null;
  }

  protected void handleReadQueue() {
    // TODO Auto-generated method stub
    
  }

  protected void error() {
    try {
      socketChannel.close();      
    }
    catch (Exception e) {
      /* */
    }
    socketChannel = null;
    if (readyState!=ReadyState.CLOSED) {
      readyState = ReadyState.CLOSED;
      callOnerror();
    }
  }
  
  protected synchronized void queue(byte data[]) throws ClosedChannelException {
    writeQueue.add(ByteBuffer.wrap(data));
    register(SelectionKey.OP_READ | SelectionKey.OP_WRITE);
  }

}

Java Source Code List

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