test/hotspot/jtreg/vmTestbase/nsk/share/jpda/SocketConnection.java - platform/libcore - Git at Google

 /*
  * Copyright (c) 2001, 2018, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
  * under the terms of the GNU General Public License version 2 only, as
  * published by the Free Software Foundation.
  *
  * This code 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 General Public License
  * version 2 for more details (a copy is included in the LICENSE file that
  * accompanied this code).
  *
  * You should have received a copy of the GNU General Public License version
  * 2 along with this work; if not, write to the Free Software Foundation,
  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  *
  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  * or visit www.oracle.com if you need additional information or have any
  * questions.
  */

 package nsk.share.jpda;

 import java.io.*;
 import java.net.*;

 import nsk.share.*;

 /**
  * This class implements basic connection channel via TCP/IP sockets.
  */
 class BasicSocketConnection {

     protected static int TRACE_LEVEL_PACKETS = 10;

     protected static int TRACE_LEVEL_THREADS = 20;

     protected static int TRACE_LEVEL_ACTIONS = 30;

     protected static int TRACE_LEVEL_SOCKETS = 40;

     protected static int TRACE_LEVEL_IO = 50;

     protected String name = null;

     protected ServerSocket serverSocket = null;

     protected Socket socket = null;

     protected InputStream sin = null;

     protected OutputStream sout = null;

     protected Process connectingProcess = null;

     protected volatile boolean connected = false;

     protected volatile boolean closed = false;

     protected volatile boolean connectionClosed = false;

     protected volatile boolean shouldStop = false;

     protected Log.Logger logger = null;

     /**
      * Make an empty connection with specified name.
      *
      * @param logger
      *                Logger object for printing log messages
      * @param name
      *                connection name
      */
     public BasicSocketConnection(Log.Logger logger, String name) {
         this.logger = logger;
         this.name = name;
     }

     /**
      * Try to bind connection to the local port.
      *
      * @param port
      *                port number to bind to
      *
      * @throws IOException
      *                 if error occured while binding
      */
     protected void tryBind(int port) throws IOException {
         logger.trace(TRACE_LEVEL_IO, "Binding for " + name + " connection to port: " + port);
         serverSocket = new ServerSocket(port, 1);
         logger.trace(TRACE_LEVEL_IO, "Bound for " + name + " connection to port: " + port);
     }

     /**
      * Bind connection to the local port for specified timeout.
      *
      * @param port
      *                port number to bind to
      * @param timeout
      *                binding timeout in milliseconds
      *
      * @throws Failure
      *                 if error ocured while binding
      */
     protected void bind(int port, long timeout) {
         BindException bindException = null;
         long timeToFinish = System.currentTimeMillis() + timeout;
         for (long i = 0; !shouldStop && (timeout == 0 || System.currentTimeMillis() < timeToFinish); i++) {
             try {
                 tryBind(port);
                 return;
             } catch (BindException e) {
                 bindException = e;
                 logger.display("Attempt #" + i + " to bind to port " + port + " failed:\n\t" + e);
                 try {
                     Thread.sleep(DebugeeBinder.CONNECT_TRY_DELAY);
                 } catch (InterruptedException ie) {
                     ie.printStackTrace(logger.getOutStream());
                     throw new Failure("Thread interrupted while binding for " + name + " connection to port " + port + ":\n\t" + ie);
                 }
             } catch (IOException e) {
                 e.printStackTrace(logger.getOutStream());
                 throw new Failure("Caught IOException while binding for " + name + " connection to port " + port + ":\n\t" + e);
             }
         }
         throw new Failure("Unable to bind for " + name + " connection to port " + port + " for " + timeout + "ms timeout:\n\t" + bindException);
     }

     /**
      * Accept connection at the bound port for specified timeout.
      *
      * @param timeout
      *                accepting timeout in milliseconds
      *
      * @throws Failure
      *                 if error occured while accepting connection
      */
     public void accept(long timeout) {
         int port = serverSocket.getLocalPort();
         logger.trace(TRACE_LEVEL_IO, "Listening for " + name + " connection at port: " + port);
         socket = null;
         try {
             if (timeout > Integer.MAX_VALUE) {
                 throw new TestBug("Too large timeout long value: " + timeout + " (can't cast it to int)");
             }

             serverSocket.setSoTimeout((int)timeout);

             long waitStartTime = System.currentTimeMillis();

             /*
              * We found that sometimes (very rarely) on Solaris ServerSocket.accept() throws InterruptedIOException
              * even if connection timeout (specified through ServerSocket.setSoTimeout) didn't expire.
              * Following code tries to catch such case and call ServerSocket.accept() while timeout didn't expire.
              */
             do {
                 try {
                     socket = serverSocket.accept();
                     logger.trace(TRACE_LEVEL_IO, "Accepted " + name + " connection at port: " + port);
                 } catch (InterruptedIOException e) {
                     long interruptTime = System.currentTimeMillis();
                     long waitTime = interruptTime - waitStartTime;

                     logger.display("Caught InterruptedIOException. Wait start time: " + waitStartTime + ", exception was thrown at: "
                             + interruptTime + ", wait time: " + (interruptTime - waitStartTime) + ", actual timeout: " + timeout);

                     // if waitTime was too small call ServerSocket.accept() one more time
                     if (!shouldStop && (waitTime < (timeout / 2))) {
                         logger.display("InterruptedIOException was thrown too early, trying to call ServerSocket.accept() one more time");
                         continue;
                     } else {
                         if (!shouldStop) {
                             logger.complain("Caught InterruptedIOException while listening for " + name + " connection at port " + port + ":\n\t" + e);
                             throw new Failure("Connection for " + name +
                                     " at port " + port +
                                     " wasn't accepted in " + timeout + "ms");
                         } else {
                             logger.display("Listening was interrupted (caught InterruptedIOException while listening for " + name + " connection at port " + port + ":\n\t" + e + ")");
                             break;
                         }
                     }
                 }
             } while (socket == null);

         } catch (IOException e) {
             if (!shouldStop) {
                 e.printStackTrace(logger.getOutStream());
                 throw new Failure("Caught IOException while listening for " + name + " connection at port " + port + ":\n\t" + e);
             } else {
                 logger.display("Listening was interrupted (caught InterruptedIOException while listening for " + name + " connection at port " + port + ":\n\t" + e + ")");
             }
         } finally {
             closeServerConnection();
         }

         if (!shouldStop) {
             if (socket == null) {
                 throw new Failure("No " + name + " connection accepted at port " + port + " for " + timeout + "ms timeout");
             }

             onConnected();
         }
     }

     /**
      * Attach connection to the remote host and port.
      *
      * @param host
      *                name of remote host to attach to
      * @param port
      *                port number to attach to
      *
      * @throws Failure
      *                 if error occured while attaching
      */
     public void attach(String host, int port) {
         try {
             logger.trace(TRACE_LEVEL_IO, "Attaching for " + name + " connection to host: " + host + ":" + port);
             socket = new Socket(host, port);
             socket.setTcpNoDelay(true);
             logger.trace(TRACE_LEVEL_IO, "Attached for " + name + " connection to host: " + host + ":" + port);
         } catch (IOException e) {
             e.printStackTrace(logger.getOutStream());
             throw new Failure("Caught IOException while attaching for " + name + " connection to " + host + ":" + port + ":\n\t" + e);
         }
         if (!shouldStop) {
             onConnected();
         }
     }

     /**
      * Continuously attach to the remote host for the specified timeout.
      *
      * @param host
      *                name of remote host to attach to
      * @param port
      *                port number to attach to
      * @param timeout
      *                attaching timeout in milliseconds
      *
      * @throws Failure
      *                 if error occured while attaching
      */
     public void continueAttach(String host, int port, long timeout) {
         socket = null;
         long timeToFinish = System.currentTimeMillis() + timeout;
         ConnectException lastException = null;
         logger.trace(TRACE_LEVEL_IO, "Attaching for " + name + " connection to host: " + host + ":" + port);
         try {
             for (long i = 0; !shouldStop && (timeout == 0 || System.currentTimeMillis() < timeToFinish); i++) {
                 try {
                     socket = new Socket(host, port);
                     logger.trace(TRACE_LEVEL_IO, "Attached for " + name + " connection to host: " + host + ":" + port);
                     break;
                 } catch (ConnectException e) {
                     logger.display("Attempt #" + i + " to attach for " + name + " connection failed:\n\t" + e);
                     lastException = e;
                     // check if listening process still alive
                     if (!checkConnectingProcess()) {
                         shouldStop = true;
                         throw new Failure("Break attaching to " + name + " connection: " + "listening process exited");
                     }
                     // sleep between attempts
                     try {
                         Thread.sleep(DebugeeBinder.CONNECT_TRY_DELAY);
                     } catch (InterruptedException ie) {
                         throw new Failure("Thread interrupted while attaching for " + name + " connection to " + host + ":" + port + ":\n\t" + ie);
                     }
                 }
             }

         } catch (IOException e) {
             e.printStackTrace(logger.getOutStream());
             throw new Failure("Caught IOException while attaching for " + name + " connection to " + host + ":" + port + ":\n\t" + e);
         }

         if (!shouldStop) {
             if (socket == null) {
                 throw new Failure("Unable to attach for " + name + " connection to " + host + ":" + port + " for " + timeout + "ms timeout:\n\t"
                         + lastException);
             }

             onConnected();
         }
     }

     /**
      * Set already bound serverSocket for further connection.
      */
     public void setServerSocket(ServerSocket serverSocket) {
         this.serverSocket = serverSocket;
     }

     /**
      * Set already connected socket for connection.
      */
     public void setSocket(Socket socket) {
         this.socket = socket;
         if (!shouldStop) {
             onConnected();
         }
     }

     /**
      * Get socket of already established connection.
      */
     public Socket getSocket() {
         return socket;
     }

     /**
      * Return true if another connecting process is still alive.
      */
     public boolean checkConnectingProcess() {
         if (connectingProcess == null) {
             // no process to check
             return true;
         }
         try {
             int exitCode = connectingProcess.exitValue();
         } catch (IllegalThreadStateException e) {
             // process is still alive
             return true;
         }
         // process exited
         return false;
     }

     /**
      * Set another connecting process to control if it is still alive.
      */
     public void setConnectingProcess(Process process) {
         connectingProcess = process;
     }

     /**
      * Check if connection is established.
      */
     public boolean isConnected() {
         return connected;
     }

     /**
      * Close socket and associated streams.
      */
     public void close() {
         if (!closed) {
             shouldStop = true;
             closeConnection();
             closed = true;
         }
     }

     /**
      * Send the specified byte throw the connection.
      */
     public void writeByte(byte b) throws IOException {
         logger.trace(TRACE_LEVEL_IO, "Writing byte: " + b);
         sout.write(b);
         sout.flush();
         logger.trace(TRACE_LEVEL_IO, "Wrote byte: " + b);
     }

     /**
      * Read a byte and return it or -1.
      */
     public int readByte() throws IOException {
         logger.trace(TRACE_LEVEL_IO, "Reading byte");
         int b = sin.read();
         logger.trace(TRACE_LEVEL_IO, "Received byte: " + b);
         return b;
     }

     /**
      * Perform some actions after connection established.
      */
     protected void onConnected() {
         if (!shouldStop) {
             setSocketOptions();
             makeSocketStreams();
             connected = true;
         }
     }

     /**
      * Set socket options after connection established.
      */
     protected void setSocketOptions() {
     }

     /**
      * Close server socket.
      */
     protected void closeServerConnection() {
         if (serverSocket != null) {
             try {
                 serverSocket.close();
                 logger.trace(TRACE_LEVEL_IO, "ServerSocket closed: " + serverSocket);
             } catch (IOException e) {
                 logger.display("# WARNING: " + "Caught IOException while closing ServerSocket of " + name + " connection:\n\t" + e);
             }
         }
     }

     /**
      * Close socket of connection to remote host.
      */
     protected void closeHostConnection() {
         if (socket != null) {
             try {
                 socket.close();
                 logger.trace(TRACE_LEVEL_IO, "Socket closed: " + socket);
             } catch (IOException e) {
                 logger.display("# WARNING: " + "Caught IOException while closing socket of " + name + " connection:\n\t" + e);
             }
         }
     }

     /**
      * Close socket streams.
      */
     protected void closeSocketStreams() {
         if (sout != null) {
             try {
                 logger.trace(TRACE_LEVEL_IO, "Closing socket output stream: " + sout);
                 sout.close();
                 logger.trace(TRACE_LEVEL_IO, "Output stream closed: " + sout);
             } catch (IOException e) {
                 logger.display("# WARNING: " + "Caught IOException while closing OutputStream of " + name + " connection:\n\t" + e);
             }
         }
         if (sin != null) {
             try {
                 logger.trace(TRACE_LEVEL_IO, "Closing socket input stream: " + sin);
                 sin.close();
                 logger.trace(TRACE_LEVEL_IO, "Input stream closed: " + sin);
             } catch (IOException e) {
                 logger.display("# WARNING: " + "Caught IOException while closing InputStream of" + name + " connection:\n\t" + e);
             }
         }
     }

     /**
      * Close sockets and associated streams.
      */
     protected void closeConnection() {
         if (connectionClosed)
             return;

         logger.trace(TRACE_LEVEL_IO, "Closing " + name + " connection");
         closeSocketStreams();
         closeHostConnection();
         closeServerConnection();
         connectionClosed = true;
     }

     /**
      * Make up socket streams after connection established.
      */
     protected void makeSocketStreams() {
         try {
             logger.trace(TRACE_LEVEL_IO, "Getting input/output socket streams for " + name + " connection");
             sout = socket.getOutputStream();
             logger.trace(TRACE_LEVEL_IO, "Got socket output stream: " + sout);
             sin = socket.getInputStream();
             logger.trace(TRACE_LEVEL_IO, "Got socket input stream: " + sin);
         } catch (IOException e) {
             e.printStackTrace(logger.getOutStream());
             throw new Failure("Caught exception while making streams for " + name + " connection:\n\t" + e);
         }
     }

 } // BasicSocketConnection

 /**
  * This class implements connection channel via TCP/IP sockets. After connection
  * established special inner threads are started, which periodically test the
  * connection by pinging each other. If ping timeout occurs connection is closed
  * and any thread waiting for read from this connection gets exception.
  *
  * @see #setPingTimeout(long)
  */
 public class SocketConnection extends BasicSocketConnection {

     private static final long PING_INTERVAL = 1 * 1000; // milliseconds

     private static byte DATA_BYTE = (byte) 0x03;

     private static byte DISCONNECT_BYTE = (byte) 0x04;

     private final Object inLock = new Object();
     private ObjectInputStream in = null;

     private final Object outLock = new Object();
     private ObjectOutputStream out = null;

     private volatile long pingTimeout = 0; // don't use ping

     /**
      * Make an empty connection with specified name.
      *
      * @param log
      *                Log object for printing log messages
      * @param name
      *                connection name
      */
     public SocketConnection(Log log, String name) {
         this(new Log.Logger(log, name + " connection> "), name);
     }

     /**
      * Make an empty connection with specified name.
      *
      * @param logger
      *                Logger object for printing log messages
      * @param name
      *                connection name
      */
     public SocketConnection(Log.Logger logger, String name) {
         super(logger, name);
     }

     /**
      * Set ping timeout in milliseconds (0 means don't use ping at all).
      */
     public void setPingTimeout(long timeout) {
         logger.display("# WARNING: Setting ping timeout for " + name + " connection ingnored: " + timeout + " ms");
         pingTimeout = timeout;
     }

     /**
      * Returns value of current ping timeout in milliseconds (0 means ping is
      * not used).
      */
     public long getPingTimeout() {
         return pingTimeout;
     }

     /**
      * Receive an object from remote host.
      */
     public Object readObject() {
         if (!isConnected()) {
             throw new Failure("Unable to read object from not established " + name + " connection");
         }

         try {
             return doReadObject();
         } catch (EOFException e) {
             return null;
         } catch (Exception e) {
             e.printStackTrace(logger.getOutStream());
             throw new Failure("Caught Exception while reading an object from " + name + " connection:\n\t" + e);
         }
     }

     /**
      * Send an object to remote host.
      */
     public void writeObject(Object object) {
         if (!isConnected()) {
             throw new Failure("Unable to send object throw not established " + name + " connection:\n\t" + object);
         }

         try {
             doWriteObject(object);
         } catch (IOException e) {
             e.printStackTrace(logger.getOutStream());
             throw new Failure("Caught IOException while writing an object to " + name + " connection:\n\t" + e);
         }
     }

     /**
      * Close socket and associated streams and finish all internal threads.
      */
     public void close() {
         if (!closed) {
             // disconnect();
             shouldStop = true;
             super.close();
             closed = true;
         }
     }

     /**
      * Perform some actions after connection has established.
      */
     protected void onConnected() {
         super.onConnected();
     }

     /**
      * Do write an object to the connection channel.
      */
     private void doWriteObject(Object object) throws IOException {
         logger.trace(TRACE_LEVEL_IO, "writing object: " + object);
         synchronized(outLock) {
             out.writeObject(object);
             out.flush();
         }
         logger.trace(TRACE_LEVEL_PACKETS, "* sent: " + object);
     }

     /**
      * Do read an object from the connection channel.
      */
     private Object doReadObject() throws IOException, ClassNotFoundException {
         logger.trace(TRACE_LEVEL_IO, "Reading object");
         Object object = null;
         synchronized(inLock) {
             object = in.readObject();
         }
         logger.trace(TRACE_LEVEL_PACKETS, "* recv: " + object);
         return object;
     }

     /**
      * Close socket streams.
      */
     protected void closeSocketStreams() {
         synchronized(outLock) {
             if (out != null) {
                 try {
                     logger.trace(TRACE_LEVEL_IO, "Closing socket output stream: " + out);
                     out.close();
                     logger.trace(TRACE_LEVEL_IO, "Output stream closed: " + out);
                 } catch (IOException e) {
                     logger.display("# WARNING: " + "Caught IOException while closing ObjectOutputStream of " + name + " connection:\n\t" + e);
                 }
             }
         }
         synchronized(inLock) {
             if (in != null) {
                 try {
                     logger.trace(TRACE_LEVEL_IO, "Closing socket input stream: " + in);
                     in.close();
                     logger.trace(TRACE_LEVEL_IO, "Input stream closed: " + in);
                 } catch (IOException e) {
                     logger.display("# WARNING: " + "Caught IOException while closing ObjectInputStream of" + name + " connection:\n\t" + e);
                 }
             }
         }
         super.closeSocketStreams();
     }

     /**
      * Close sockets and associated streams.
      */
     protected void closeConnection() {
         if (connectionClosed)
             return;
         connected = false;
         shouldStop = true;
         super.closeConnection();
     }

     /**
      * Make up object streams for socket.
      */
     protected void makeSocketStreams() {
         try {
             logger.trace(TRACE_LEVEL_IO, "Making input/output object streams for " + name + " connection");
             synchronized(outLock) {
                 out = new ObjectOutputStream(socket.getOutputStream());
                 out.flush();
             }
             logger.trace(TRACE_LEVEL_IO, "Output stream created: " + out);
             synchronized(inLock) {
                 in = new ObjectInputStream(socket.getInputStream());
             }
             logger.trace(TRACE_LEVEL_IO, "Input stream created: " + in);
         } catch (IOException e) {
             e.printStackTrace(logger.getOutStream());
             throw new Failure("Caught exception while making streams for " + name + " connection:\n\t" + e);
         }
     }

 } // SocketConnection
	/*
	* Copyright (c) 2001, 2018, Oracle and/or its affiliates. All rights reserved.
	* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
	*
	* This code is free software; you can redistribute it and/or modify it
	* under the terms of the GNU General Public License version 2 only, as
	* published by the Free Software Foundation.
	*
	* This code 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 General Public License
	* version 2 for more details (a copy is included in the LICENSE file that
	* accompanied this code).
	*
	* You should have received a copy of the GNU General Public License version
	* 2 along with this work; if not, write to the Free Software Foundation,
	* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
	*
	* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
	* or visit www.oracle.com if you need additional information or have any
	* questions.
	*/

	package nsk.share.jpda;

	import java.io.*;
	import java.net.*;

	import nsk.share.*;

	/**
	* This class implements basic connection channel via TCP/IP sockets.
	*/
	class BasicSocketConnection {

	protected static int TRACE_LEVEL_PACKETS = 10;

	protected static int TRACE_LEVEL_THREADS = 20;

	protected static int TRACE_LEVEL_ACTIONS = 30;

	protected static int TRACE_LEVEL_SOCKETS = 40;

	protected static int TRACE_LEVEL_IO = 50;

	protected String name = null;

	protected ServerSocket serverSocket = null;

	protected Socket socket = null;

	protected InputStream sin = null;

	protected OutputStream sout = null;

	protected Process connectingProcess = null;

	protected volatile boolean connected = false;

	protected volatile boolean closed = false;

	protected volatile boolean connectionClosed = false;

	protected volatile boolean shouldStop = false;

	protected Log.Logger logger = null;

	/**
	* Make an empty connection with specified name.
	*
	* @param logger
	* Logger object for printing log messages
	* @param name
	* connection name
	*/
	public BasicSocketConnection(Log.Logger logger, String name) {
	this.logger = logger;
	this.name = name;
	}

	/**
	* Try to bind connection to the local port.
	*
	* @param port
	* port number to bind to
	*
	* @throws IOException
	* if error occured while binding
	*/
	protected void tryBind(int port) throws IOException {
	logger.trace(TRACE_LEVEL_IO, "Binding for " + name + " connection to port: " + port);
	serverSocket = new ServerSocket(port, 1);
	logger.trace(TRACE_LEVEL_IO, "Bound for " + name + " connection to port: " + port);
	}

	/**
	* Bind connection to the local port for specified timeout.
	*
	* @param port
	* port number to bind to
	* @param timeout
	* binding timeout in milliseconds
	*
	* @throws Failure
	* if error ocured while binding
	*/
	protected void bind(int port, long timeout) {
	BindException bindException = null;
	long timeToFinish = System.currentTimeMillis() + timeout;
	for (long i = 0; !shouldStop && (timeout == 0 \|\| System.currentTimeMillis() < timeToFinish); i++) {
	try {
	tryBind(port);
	return;
	} catch (BindException e) {
	bindException = e;
	logger.display("Attempt #" + i + " to bind to port " + port + " failed:\n\t" + e);
	try {
	Thread.sleep(DebugeeBinder.CONNECT_TRY_DELAY);
	} catch (InterruptedException ie) {
	ie.printStackTrace(logger.getOutStream());
	throw new Failure("Thread interrupted while binding for " + name + " connection to port " + port + ":\n\t" + ie);
	}
	} catch (IOException e) {
	e.printStackTrace(logger.getOutStream());
	throw new Failure("Caught IOException while binding for " + name + " connection to port " + port + ":\n\t" + e);
	}
	}
	throw new Failure("Unable to bind for " + name + " connection to port " + port + " for " + timeout + "ms timeout:\n\t" + bindException);
	}

	/**
	* Accept connection at the bound port for specified timeout.
	*
	* @param timeout
	* accepting timeout in milliseconds
	*
	* @throws Failure
	* if error occured while accepting connection
	*/
	public void accept(long timeout) {
	int port = serverSocket.getLocalPort();
	logger.trace(TRACE_LEVEL_IO, "Listening for " + name + " connection at port: " + port);
	socket = null;
	try {
	if (timeout > Integer.MAX_VALUE) {
	throw new TestBug("Too large timeout long value: " + timeout + " (can't cast it to int)");
	}

	serverSocket.setSoTimeout((int)timeout);

	long waitStartTime = System.currentTimeMillis();

	/*
	* We found that sometimes (very rarely) on Solaris ServerSocket.accept() throws InterruptedIOException
	* even if connection timeout (specified through ServerSocket.setSoTimeout) didn't expire.
	* Following code tries to catch such case and call ServerSocket.accept() while timeout didn't expire.
	*/
	do {
	try {
	socket = serverSocket.accept();
	logger.trace(TRACE_LEVEL_IO, "Accepted " + name + " connection at port: " + port);
	} catch (InterruptedIOException e) {
	long interruptTime = System.currentTimeMillis();
	long waitTime = interruptTime - waitStartTime;

	logger.display("Caught InterruptedIOException. Wait start time: " + waitStartTime + ", exception was thrown at: "
	+ interruptTime + ", wait time: " + (interruptTime - waitStartTime) + ", actual timeout: " + timeout);

	// if waitTime was too small call ServerSocket.accept() one more time
	if (!shouldStop && (waitTime < (timeout / 2))) {
	logger.display("InterruptedIOException was thrown too early, trying to call ServerSocket.accept() one more time");
	continue;
	} else {
	if (!shouldStop) {
	logger.complain("Caught InterruptedIOException while listening for " + name + " connection at port " + port + ":\n\t" + e);
	throw new Failure("Connection for " + name +
	" at port " + port +
	" wasn't accepted in " + timeout + "ms");
	} else {
	logger.display("Listening was interrupted (caught InterruptedIOException while listening for " + name + " connection at port " + port + ":\n\t" + e + ")");
	break;
	}
	}
	}
	} while (socket == null);

	} catch (IOException e) {
	if (!shouldStop) {
	e.printStackTrace(logger.getOutStream());
	throw new Failure("Caught IOException while listening for " + name + " connection at port " + port + ":\n\t" + e);
	} else {
	logger.display("Listening was interrupted (caught InterruptedIOException while listening for " + name + " connection at port " + port + ":\n\t" + e + ")");
	}
	} finally {
	closeServerConnection();
	}

	if (!shouldStop) {
	if (socket == null) {
	throw new Failure("No " + name + " connection accepted at port " + port + " for " + timeout + "ms timeout");
	}

	onConnected();
	}
	}

	/**
	* Attach connection to the remote host and port.
	*
	* @param host
	* name of remote host to attach to
	* @param port
	* port number to attach to
	*
	* @throws Failure
	* if error occured while attaching
	*/
	public void attach(String host, int port) {
	try {
	logger.trace(TRACE_LEVEL_IO, "Attaching for " + name + " connection to host: " + host + ":" + port);
	socket = new Socket(host, port);
	socket.setTcpNoDelay(true);
	logger.trace(TRACE_LEVEL_IO, "Attached for " + name + " connection to host: " + host + ":" + port);
	} catch (IOException e) {
	e.printStackTrace(logger.getOutStream());
	throw new Failure("Caught IOException while attaching for " + name + " connection to " + host + ":" + port + ":\n\t" + e);
	}
	if (!shouldStop) {
	onConnected();
	}
	}

	/**
	* Continuously attach to the remote host for the specified timeout.
	*
	* @param host
	* name of remote host to attach to
	* @param port
	* port number to attach to
	* @param timeout
	* attaching timeout in milliseconds
	*
	* @throws Failure
	* if error occured while attaching
	*/
	public void continueAttach(String host, int port, long timeout) {
	socket = null;
	long timeToFinish = System.currentTimeMillis() + timeout;
	ConnectException lastException = null;
	logger.trace(TRACE_LEVEL_IO, "Attaching for " + name + " connection to host: " + host + ":" + port);
	try {
	for (long i = 0; !shouldStop && (timeout == 0 \|\| System.currentTimeMillis() < timeToFinish); i++) {
	try {
	socket = new Socket(host, port);
	logger.trace(TRACE_LEVEL_IO, "Attached for " + name + " connection to host: " + host + ":" + port);
	break;
	} catch (ConnectException e) {
	logger.display("Attempt #" + i + " to attach for " + name + " connection failed:\n\t" + e);
	lastException = e;
	// check if listening process still alive
	if (!checkConnectingProcess()) {
	shouldStop = true;
	throw new Failure("Break attaching to " + name + " connection: " + "listening process exited");
	}
	// sleep between attempts
	try {
	Thread.sleep(DebugeeBinder.CONNECT_TRY_DELAY);
	} catch (InterruptedException ie) {
	throw new Failure("Thread interrupted while attaching for " + name + " connection to " + host + ":" + port + ":\n\t" + ie);
	}
	}
	}

	} catch (IOException e) {
	e.printStackTrace(logger.getOutStream());
	throw new Failure("Caught IOException while attaching for " + name + " connection to " + host + ":" + port + ":\n\t" + e);
	}

	if (!shouldStop) {
	if (socket == null) {
	throw new Failure("Unable to attach for " + name + " connection to " + host + ":" + port + " for " + timeout + "ms timeout:\n\t"
	+ lastException);
	}

	onConnected();
	}
	}

	/**
	* Set already bound serverSocket for further connection.
	*/
	public void setServerSocket(ServerSocket serverSocket) {
	this.serverSocket = serverSocket;
	}

	/**
	* Set already connected socket for connection.
	*/
	public void setSocket(Socket socket) {
	this.socket = socket;
	if (!shouldStop) {
	onConnected();
	}
	}

	/**
	* Get socket of already established connection.
	*/
	public Socket getSocket() {
	return socket;
	}

	/**
	* Return true if another connecting process is still alive.
	*/
	public boolean checkConnectingProcess() {
	if (connectingProcess == null) {
	// no process to check
	return true;
	}
	try {
	int exitCode = connectingProcess.exitValue();
	} catch (IllegalThreadStateException e) {
	// process is still alive
	return true;
	}
	// process exited
	return false;
	}

	/**
	* Set another connecting process to control if it is still alive.
	*/
	public void setConnectingProcess(Process process) {
	connectingProcess = process;
	}

	/**
	* Check if connection is established.
	*/
	public boolean isConnected() {
	return connected;
	}

	/**
	* Close socket and associated streams.
	*/
	public void close() {
	if (!closed) {
	shouldStop = true;
	closeConnection();
	closed = true;
	}
	}

	/**
	* Send the specified byte throw the connection.
	*/
	public void writeByte(byte b) throws IOException {
	logger.trace(TRACE_LEVEL_IO, "Writing byte: " + b);
	sout.write(b);
	sout.flush();
	logger.trace(TRACE_LEVEL_IO, "Wrote byte: " + b);
	}

	/**
	* Read a byte and return it or -1.
	*/
	public int readByte() throws IOException {
	logger.trace(TRACE_LEVEL_IO, "Reading byte");
	int b = sin.read();
	logger.trace(TRACE_LEVEL_IO, "Received byte: " + b);
	return b;
	}

	/**
	* Perform some actions after connection established.
	*/
	protected void onConnected() {
	if (!shouldStop) {
	setSocketOptions();
	makeSocketStreams();
	connected = true;
	}
	}

	/**
	* Set socket options after connection established.
	*/
	protected void setSocketOptions() {
	}

	/**
	* Close server socket.
	*/
	protected void closeServerConnection() {
	if (serverSocket != null) {
	try {
	serverSocket.close();
	logger.trace(TRACE_LEVEL_IO, "ServerSocket closed: " + serverSocket);
	} catch (IOException e) {
	logger.display("# WARNING: " + "Caught IOException while closing ServerSocket of " + name + " connection:\n\t" + e);
	}
	}
	}

	/**
	* Close socket of connection to remote host.
	*/
	protected void closeHostConnection() {
	if (socket != null) {
	try {
	socket.close();
	logger.trace(TRACE_LEVEL_IO, "Socket closed: " + socket);
	} catch (IOException e) {
	logger.display("# WARNING: " + "Caught IOException while closing socket of " + name + " connection:\n\t" + e);
	}
	}
	}

	/**
	* Close socket streams.
	*/
	protected void closeSocketStreams() {
	if (sout != null) {
	try {
	logger.trace(TRACE_LEVEL_IO, "Closing socket output stream: " + sout);
	sout.close();
	logger.trace(TRACE_LEVEL_IO, "Output stream closed: " + sout);
	} catch (IOException e) {
	logger.display("# WARNING: " + "Caught IOException while closing OutputStream of " + name + " connection:\n\t" + e);
	}
	}
	if (sin != null) {
	try {
	logger.trace(TRACE_LEVEL_IO, "Closing socket input stream: " + sin);
	sin.close();
	logger.trace(TRACE_LEVEL_IO, "Input stream closed: " + sin);
	} catch (IOException e) {
	logger.display("# WARNING: " + "Caught IOException while closing InputStream of" + name + " connection:\n\t" + e);
	}
	}
	}

	/**
	* Close sockets and associated streams.
	*/
	protected void closeConnection() {
	if (connectionClosed)
	return;

	logger.trace(TRACE_LEVEL_IO, "Closing " + name + " connection");
	closeSocketStreams();
	closeHostConnection();
	closeServerConnection();
	connectionClosed = true;
	}

	/**
	* Make up socket streams after connection established.
	*/
	protected void makeSocketStreams() {
	try {
	logger.trace(TRACE_LEVEL_IO, "Getting input/output socket streams for " + name + " connection");
	sout = socket.getOutputStream();
	logger.trace(TRACE_LEVEL_IO, "Got socket output stream: " + sout);
	sin = socket.getInputStream();
	logger.trace(TRACE_LEVEL_IO, "Got socket input stream: " + sin);
	} catch (IOException e) {
	e.printStackTrace(logger.getOutStream());
	throw new Failure("Caught exception while making streams for " + name + " connection:\n\t" + e);
	}
	}

	} // BasicSocketConnection

	/**
	* This class implements connection channel via TCP/IP sockets. After connection
	* established special inner threads are started, which periodically test the
	* connection by pinging each other. If ping timeout occurs connection is closed
	* and any thread waiting for read from this connection gets exception.
	*
	* @see #setPingTimeout(long)
	*/
	public class SocketConnection extends BasicSocketConnection {

	private static final long PING_INTERVAL = 1 * 1000; // milliseconds

	private static byte DATA_BYTE = (byte) 0x03;

	private static byte DISCONNECT_BYTE = (byte) 0x04;

	private final Object inLock = new Object();
	private ObjectInputStream in = null;

	private final Object outLock = new Object();
	private ObjectOutputStream out = null;

	private volatile long pingTimeout = 0; // don't use ping

	/**
	* Make an empty connection with specified name.
	*
	* @param log
	* Log object for printing log messages
	* @param name
	* connection name
	*/
	public SocketConnection(Log log, String name) {
	this(new Log.Logger(log, name + " connection> "), name);
	}

	/**
	* Make an empty connection with specified name.
	*
	* @param logger
	* Logger object for printing log messages
	* @param name
	* connection name
	*/
	public SocketConnection(Log.Logger logger, String name) {
	super(logger, name);
	}

	/**
	* Set ping timeout in milliseconds (0 means don't use ping at all).
	*/
	public void setPingTimeout(long timeout) {
	logger.display("# WARNING: Setting ping timeout for " + name + " connection ingnored: " + timeout + " ms");
	pingTimeout = timeout;
	}

	/**
	* Returns value of current ping timeout in milliseconds (0 means ping is
	* not used).
	*/
	public long getPingTimeout() {
	return pingTimeout;
	}

	/**
	* Receive an object from remote host.
	*/
	public Object readObject() {
	if (!isConnected()) {
	throw new Failure("Unable to read object from not established " + name + " connection");
	}

	try {
	return doReadObject();
	} catch (EOFException e) {
	return null;
	} catch (Exception e) {
	e.printStackTrace(logger.getOutStream());
	throw new Failure("Caught Exception while reading an object from " + name + " connection:\n\t" + e);
	}
	}

	/**
	* Send an object to remote host.
	*/
	public void writeObject(Object object) {
	if (!isConnected()) {
	throw new Failure("Unable to send object throw not established " + name + " connection:\n\t" + object);
	}

	try {
	doWriteObject(object);
	} catch (IOException e) {
	e.printStackTrace(logger.getOutStream());
	throw new Failure("Caught IOException while writing an object to " + name + " connection:\n\t" + e);
	}
	}

	/**
	* Close socket and associated streams and finish all internal threads.
	*/
	public void close() {
	if (!closed) {
	// disconnect();
	shouldStop = true;
	super.close();
	closed = true;
	}
	}

	/**
	* Perform some actions after connection has established.
	*/
	protected void onConnected() {
	super.onConnected();
	}

	/**
	* Do write an object to the connection channel.
	*/
	private void doWriteObject(Object object) throws IOException {
	logger.trace(TRACE_LEVEL_IO, "writing object: " + object);
	synchronized(outLock) {
	out.writeObject(object);
	out.flush();
	}
	logger.trace(TRACE_LEVEL_PACKETS, "* sent: " + object);
	}

	/**
	* Do read an object from the connection channel.
	*/
	private Object doReadObject() throws IOException, ClassNotFoundException {
	logger.trace(TRACE_LEVEL_IO, "Reading object");
	Object object = null;
	synchronized(inLock) {
	object = in.readObject();
	}
	logger.trace(TRACE_LEVEL_PACKETS, "* recv: " + object);
	return object;
	}

	/**
	* Close socket streams.
	*/
	protected void closeSocketStreams() {
	synchronized(outLock) {
	if (out != null) {
	try {
	logger.trace(TRACE_LEVEL_IO, "Closing socket output stream: " + out);
	out.close();
	logger.trace(TRACE_LEVEL_IO, "Output stream closed: " + out);
	} catch (IOException e) {
	logger.display("# WARNING: " + "Caught IOException while closing ObjectOutputStream of " + name + " connection:\n\t" + e);
	}
	}
	}
	synchronized(inLock) {
	if (in != null) {
	try {
	logger.trace(TRACE_LEVEL_IO, "Closing socket input stream: " + in);
	in.close();
	logger.trace(TRACE_LEVEL_IO, "Input stream closed: " + in);
	} catch (IOException e) {
	logger.display("# WARNING: " + "Caught IOException while closing ObjectInputStream of" + name + " connection:\n\t" + e);
	}
	}
	}
	super.closeSocketStreams();
	}

	/**
	* Close sockets and associated streams.
	*/
	protected void closeConnection() {
	if (connectionClosed)
	return;
	connected = false;
	shouldStop = true;
	super.closeConnection();
	}

	/**
	* Make up object streams for socket.
	*/
	protected void makeSocketStreams() {
	try {
	logger.trace(TRACE_LEVEL_IO, "Making input/output object streams for " + name + " connection");
	synchronized(outLock) {
	out = new ObjectOutputStream(socket.getOutputStream());
	out.flush();
	}
	logger.trace(TRACE_LEVEL_IO, "Output stream created: " + out);
	synchronized(inLock) {
	in = new ObjectInputStream(socket.getInputStream());
	}
	logger.trace(TRACE_LEVEL_IO, "Input stream created: " + in);
	} catch (IOException e) {
	e.printStackTrace(logger.getOutStream());
	throw new Failure("Caught exception while making streams for " + name + " connection:\n\t" + e);
	}
	}

	} // SocketConnection