tcpconnection.java

SMC takes a state machine stored in a .sm file and generates a State pattern in twelve programming l

//
// The contents of this file are subject to the Mozilla Public
// License Version 1.1 (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.mozilla.org/MPL/
// 
// Software distributed under the License is distributed on an
// "AS IS" basis, WITHOUT WARRANTY OF ANY KIND, either express or
// implied. See the License for the specific language governing
// rights and limitations under the License.
// 
// The Original Code is State Machine Compiler (SMC).
// 
// The Initial Developer of the Original Code is Charles W. Rapp.
// Portions created by Charles W. Rapp are
// Copyright (C) 2000 - 2007. Charles W. Rapp.
// All Rights Reserved.
// 
// Contributor(s): 
//
// Name
//  TcpConnection.java
//
// Description
//  Both TCP client and server sockets are TCP connections.
//
// RCS ID
// $Id: TcpConnection.java,v 1.7 2007/12/28 12:34:40 cwrapp Exp $
//
// CHANGE LOG
// $Log: TcpConnection.java,v $
// Revision 1.7  2007/12/28 12:34:40  cwrapp
// Version 5.0.1 check-in.
//
// Revision 1.6  2005/11/07 19:34:54  cwrapp
// Changes in release 4.3.0:
// New features:
//
// + Added -reflect option for Java, C#, VB.Net and Tcl code
//   generation. When used, allows applications to query a state
//   about its supported transitions. Returns a list of transition
//   names. This feature is useful to GUI developers who want to
//   enable/disable features based on the current state. See
//   Programmer's Manual section 11: On Reflection for more
//   information.
//
// + Updated LICENSE.txt with a missing final paragraph which allows
//   MPL 1.1 covered code to work with the GNU GPL.
//
// + Added a Maven plug-in and an ant task to a new tools directory.
//   Added Eiten Suez's SMC tutorial (in PDF) to a new docs
//   directory.
//
// Fixed the following bugs:
//
// + (GraphViz) DOT file generation did not properly escape
//   double quotes appearing in transition guards. This has been
//   corrected.
//
// + A note: the SMC FAQ incorrectly stated that C/C++ generated
//   code is thread safe. This is wrong. C/C++ generated is
//   certainly *not* thread safe. Multi-threaded C/C++ applications
//   are required to synchronize access to the FSM to allow for
//   correct performance.
//
// + (Java) The generated getState() method is now public.
//
// Revision 1.5  2005/05/28 13:51:24  cwrapp
// Update Java examples 1 - 7.
//
// Revision 1.0  2003/12/14 20:19:31  charlesr
// Initial revision
//

package smc_ex6;

import java.io.IOException;
import java.lang.reflect.Method;
import java.net.DatagramPacket;
import java.net.DatagramSocket;
import java.net.InetAddress;

public abstract class TcpConnection
    implements DatagramSocketListener,
               TimerListener
{
//---------------------------------------------------------------
// Member methods.
//

    public final void close()
    {
        synchronized (this)
        {
            try
            {
                // REFLECTION
                // Uncomment the following line to output
                // transitions.
                // _outputTransitions();

                _fsm.Close();

                // Wait for the connection to close before
                // returning.
                while (_async_socket != null)
                {
                    try
                    {
                        this.wait();
                    }
                    catch (InterruptedException interrupt)
                    {}
                }
            }
            finally
            {
                this.notify();
            }
        }

        return;
    }

    public final void
        handleReceive(DatagramPacket packet,
                      AsyncDatagramSocket dgram_socket)
    {
        synchronized (this)
        {
            try
            {
                TcpSegment segment = new TcpSegment(packet);
                Object[] args = new Object[1];

                // Generate the appropriate transition based on
                // the header flags.
                args[0] = segment;

                // DEBUG
//                 System.out.println(
//                     "Receive event from " +
//                     packet.getAddress() +
//                     ":" +
//                     Integer.toString(packet.getPort()) +
//                     ":\n" +
//                     segment);

                // REFLECTION
                // Uncomment the following line to output
                // transitions.
                // _outputTransitions();

                _transition_table[segment.getFlags()].invoke(
                    _fsm, args);
            }
            catch (Exception jex)
            {
                System.err.println(jex);
                jex.printStackTrace();
            }
            finally
            {
                this.notify();
            }
        }

        return;
    }

    public final void
        handleError(Exception e,
                    AsyncDatagramSocket dgram_socket)
    {
        // TODO
        // Generate the appropriate transition.
    }

    public final void handleTimeout(String name)
    {
        synchronized (this)
        {
            try
            {
                // REFLECTION
                // Uncomment the following line to output
                // transitions.
                // _outputTransitions();

                if (name.compareTo("CONN_ACK_TIMER") == 0)
                {
                    _fsm.ConnAckTimeout();
                }
                else if (name.compareTo("TRANS_ACK_TIMER") == 0)
                {
                    _fsm.TransAckTimeout();
                }
                else if (name.compareTo("CLOSE_ACK_TIMER") == 0)
                {
                    _fsm.CloseAckTimeout();
                }
                else if (name.compareTo("CLOSE_TIMER") == 0)
                {
                    _fsm.CloseTimeout();
                }
                else if (name.compareTo("SERVER_OPENED") == 0)
                {
                    _fsm.Opened();
                }
                else if (name.compareTo("CLIENT_OPENED") == 0)
                {
                    _fsm.Opened(_address, _port);
                }
                else if (name.compareTo("OPEN_FAILED") == 0)
                {
                    _fsm.OpenFailed(_errorMessage);
                    _errorMessage = null;
                }
            }
            finally
            {
                this.notify();
            }
        }

        return;
    }

    // Server socket constructor.
    protected TcpConnection(TcpConnectionListener listener)
    {
        _listener = listener;
        _fsm = new TcpConnectionContext(this);
        _sequence_number = 0;
        _async_socket = null;
        _address = null;
        _port = -1;
        _server = null;
        _errorMessage = null;

        // REFLECTION
        // Turn on FSM debugging.
        // _fsm.setDebugFlag(true);

        return;
    }

    // "Accepted" socket constructor.
    protected TcpConnection(InetAddress address,
                            int port,
                            DatagramSocket socket,
                            int sequence_number,
                            TcpServer server,
                            TcpConnectionListener listener)
    {
        _async_socket = new AsyncDatagramSocket(socket, this);
        _address = address;
        _port = port;
        _sequence_number = sequence_number;
        _server = server;
        _errorMessage = null;
        _listener = listener;
        _fsm = new TcpConnectionContext(this);

        // REFLECTION
        // Turn on FSM debugging.
        // _fsm.setDebugFlag(true);

        _async_socket.start();

        return;
    }

    protected final void passiveOpen(int port)
    {
        synchronized (this)
        {
            try
            {
                // REFLECTION
                // Uncomment the following line to output
                // transitions.
                // _outputTransitions();

                _fsm.PassiveOpen(port);
            }
            finally
            {
                this.notify();
            }
        }

        return;
    }

    protected final void activeOpen(InetAddress address, int port)
    {
        synchronized (this)
        {
            try
            {
                // REFLECTION
                // Uncomment the following line to output
                // transitions.
                // _outputTransitions();

                _fsm.ActiveOpen(address, port);
            }
            finally
            {
                this.notify();
            }
        }

        return;
    }

    protected final void acceptOpen(TcpSegment segment)
    {
        synchronized (this)
        {
            try
            {
                // REFLECTION
                // Uncomment the following line to output
                // transitions.
                // _outputTransitions();

                _fsm.AcceptOpen(segment);
            }
            finally
            {
                this.notify();
            }
        }

        return;
    }

    protected final void
        setListener(TcpConnectionListener listener)
            throws IllegalStateException
    {
        if (_listener != null)
        {
            throw(
                new IllegalStateException(
                    "Socket listener already set"));
        }
        else
        {
            _listener = listener;
        }

        return;
    }

    protected void transmit(byte[] data, int offset, int length)
    {
        synchronized (this)
        {
            try
            {
                // REFLECTION
                // Uncomment the following lines to output
                // transitions.
                // _outputTransitions();

                _fsm.Transmit(data, offset, length);
            }
            finally
            {
                this.notify();
            }
        }

        return;
    }

    //-----------------------------------------------------------
    // State Map Actions.
    //
    /* package */ InetAddress getFarAddress()
    {
        return (_address);
    }

    /* package */ int getFarPort()
    {
        return (_port);
    }

    /* package */ int getSequenceNumber()
    {
        return (_sequence_number);
    }

    /* package */ void openServerSocket(int port)
    {
        DatagramSocket socket;

        try
        {
            // Create the asynchronous datagram socket listener and
            // start it running.
            socket = new DatagramSocket(port);
            _async_socket = new AsyncDatagramSocket(socket, this);
            _async_socket.start();

            // Set the sequence number.
            _sequence_number = ISN;

            startTimer("SERVER_OPENED", MIN_TIMEOUT);
            
        }
        catch (Exception jex)
        {
            _errorMessage = jex.getMessage();
            startTimer("OPEN_FAILED", MIN_TIMEOUT);
        }

        return;
    }

    /* package */ void openClientSocket(InetAddress address,
                                        int port)
    {
        DatagramSocket socket;

        try
        {
            socket = new DatagramSocket();

            _address = address;
            _port = port;
            _async_socket =
                    new AsyncDatagramSocket(socket, this);
            _async_socket.start();

            // Set the sequence number.
            _sequence_number = ISN;

            startTimer("CLIENT_OPENED", MIN_TIMEOUT);
        }
        catch (Exception jex)
        {
            // Do not issue a transition now since we are already
            // in a transition. Set a 1 millisecond timer and
            // issue transition when timer expires.
            _errorMessage = jex.toString();
            startTimer("OPEN_FAILED", MIN_TIMEOUT);
        }

        return;