path: root/src/IvyClient.java

package fr.dgac.ivy ;

import java.lang.Thread;
import java.net.*;
import java.io.*;
import java.util.*;
import gnu.regexp.*;

/**
 * A private Class for the the peers on the bus.
 *
 * @author	François-Régis Colin
 * @author	Yannick Jestin
 * @author	<a href="http://www.tls.cena.fr/products/ivy/">http://www.tls.cena.fr/products/ivy/</a>
 *
 * each time a connexion is made with a remote peer, the regexp are exchanged
 * once ready, a ready message is sent, and then we can send messages, 
 * die messages, direct messages, add or remove regexps, or quit. A thread is
 * created for each remote client.
 */

public class IvyClient extends Thread {
    
  /* the protocol magic numbers */
  final static int Bye = 0;	/* end of the peer */
  final static int AddRegexp = 1;/* the peer adds a regexp */
  final static int Msg = 2 ;	/* the peer sends a message */
  final static int Error = 3; 	/* error message */
  final static int DelRegexp = 4;/* the peer removes one of his regex */
  final static int EndRegexp = 5;/* no more regexp in the handshake */
  final static int SchizoToken = 6; /* avoid race condition in concurrent connexions */
  final static int DirectMsg = 7;/* the peer sends a direct message */
  final static int Die = 8;  /* the peer wants us to quit */
  final static String StartArg = "\002";/* begin of arguments */
  final static String EndArg = "\003"; /* end of arguments */

  private static boolean debug = (System.getProperty("IVY_DEBUG")!=null) ;
  private Ivy bus;
  private Socket socket;
  private BufferedReader in;
  private OutputStream out;
  private Hashtable regexp_in = new Hashtable();
  private Hashtable regexp_text = new Hashtable();
  private String appName;
  private int appPort;
  private boolean gardefou=true;
  private boolean peerCalling;

  IvyClient(Ivy bus, Socket socket,boolean peerCalling) throws IOException {
    appName = "Unkown";
    appPort = 0;
    this.bus = bus;
    this.socket = socket;
    this.peerCalling=peerCalling;
    in = new BufferedReader(new InputStreamReader(socket.getInputStream()));
    out = socket.getOutputStream();
    Hashtable regexps=bus.regexp_out;
    // sends our ID, whether we initiated the connexion or not
    // the ID is the couple "host name,application Port", the host name
    // information is in the socket itself, the port is not known if we
    // initiate the connexion
    send(SchizoToken,bus.applicationPort,bus.appName);
    // sends our regexps to the peer
    for (Enumeration e = regexps.keys(); e.hasMoreElements(); ) {
      Integer key = (Integer)e.nextElement();
      sendRegexp( key.intValue(),(String)regexps.get(key));
    }
    send( EndRegexp,0,"");
    // spawns a thread to manage the incoming traffic on this
    // socket. We should be ready to receive messages now.
    start();
  }


  String getApplicationName() { return appName ; }

  /**
   *  allow an Ivy package class to access the list of regexps at a
   *  given time.
   *  perhaps we should implement a new IvyApplicationListener method to
   *  allow the notification of regexp addition and deletion
   */
  Enumeration getRegexps() { return regexp_text.elements(); }
  int getAppPort() { return appPort ; }

  /* perhaps we should perform some checking here */
  void sendRegexp(int id,String regexp) {send(AddRegexp,id,regexp);}
  public void delRegexp(int id) {send( DelRegexp,id,"");}

  /**
   * sends the substrings of a message to the peer for each matching regexp.
   * @param message the string that will be match-tested
   * @return the number of messages sent to the peer
   */
  int sendMsg( String message ) {
    int count = 0;
    for (Enumeration e = regexp_in.keys();e.hasMoreElements();) {
      Integer key = (Integer)e.nextElement();
      RE regexp = (RE)regexp_in.get(key);
      REMatch result = regexp.getMatch(message);
      if ( result != null ) {
        send(Msg,key,regexp.getNumSubs(),result);
	count++;
      }
    }
    return count;
  }
  
  /**
   * closes the connexion to the peer.
   * @param msg the debug information
   * the thread managing the socket is stopped
   */
  void close(String msg) throws IOException {
    traceDebug( msg );
    socket.close(); // TODO it seems it doesnt stop the thread
    out.close();
    in.close();
    gardefou=false;
  }

  /**
   * compares two peers the id is the couple (host,service port).
   * @param clnt the other peer
   * @return true if the peers are similir. This should not happen, it is bad
   * © ® (tm)
   */
  boolean sameClient( IvyClient clnt ) {
    return ( appPort != 0 && appPort == clnt.appPort )
      && ( getRemoteAddress() == clnt.getRemoteAddress() ) ;
  }

  /**
   * the code of the thread handling the incoming messages.
   * this thread stops (at least it should) when the socket is closed
   * or when gardefou=false
   */
  public void run() {
    String msg = null;
    try {
      traceDebug("Connected from "+ socket.getInetAddress().getHostName()+
                 ":"+socket.getPort());
      while ( gardefou && ((msg=in.readLine()) != null )) {
	int msgtype;	// type of the last message received
	Integer msgid;	// ID of the last message received
	RE regexp = null; // compiled regexp
	String token = null;
	/*
	 * First stage: extract the message
	 */
        StringTokenizer st = new StringTokenizer(msg);
        if(!st.hasMoreTokens()){close("Bad format no type '"+msg+"'");break;}
        token=st.nextToken();
        if (token.length()==0){close("Bad format no type '"+msg+"'");break;}
        try {
	  msgtype  = Integer.parseInt(token);
	} catch ( NumberFormatException e ) {
          close("Bad format error parsing type'"+msg+"'");
          break;
        }
        if(!st.hasMoreTokens()){close("Bad format no id '"+msg+"'");break;}
        token=st.nextToken(StartArg);
	/*
	 * TODO 
	 * this doesn't work on jdk1.3 !!!
	 * the token equals " 3992", which provoques a NumberFormatException
	 */
        try {
	  msgid=Integer.valueOf(token);
	} catch ( NumberFormatException e ) {
          close("Bad format error parsing id '"+token+"'");
          break;
        }
	String msgarg="";
	if (st.hasMoreTokens()) msgarg=st.nextToken("\n");
	/*
	 * second stage: process the message
	 */
	switch (msgtype) {
	case Bye: break;
	case AddRegexp:
          if ( bus.CheckRegexp(msgarg) ) {
            try {
	      regexp_in.put(msgid,new RE(msgarg));
	      regexp_text.put(msgid,msgarg);
	    } catch (REException e) {
              System.err.println("Bad pattern: "+e.getMessage());
            }
	  } else {
	    System.err.println(
	   "Warning exp='"+msgarg+"' can't match removing from "+appName);
	  }
	  break;
	case DelRegexp:
	  regexp_in.remove(msgid);
	  regexp_text.remove(msgid);
	  break;
	case EndRegexp:
	  bus.connect(this);
	  /* TODO
	   * BUG ?  the peer is perhaps not ready to handle this message
	   * an assymetric processing should be written
	   */
	  if (bus.ready_message!=null) sendMsg(bus.ready_message);
	  break;
	case Msg:
	  try {
	    bus.callCallback(this,msgid,msgarg);
	  } catch (IvyException ie) {
	    // calling an inexistant callback
	    System.err.println("calling an inexistant callback, the caller must be wrong !");
	  }
	  break;
	case Error:
	  traceDebug("Error msg "+msgid+" "+msgarg);
	  break;
	case SchizoToken:
	  appName=msgarg;
	  appPort=msgid.intValue();
	  if ( bus.checkConnected(this) ) {
	    close("Quitting Application already connected");
	    System.err.println("Rare ! A concurrent connect occured");
          }
	  break;
	case DirectMsg:
	  bus.directMessage( this, msgid.intValue(), msgarg );
	  break;
	case Die:
	  bus.die( this,msgid.intValue());
	  break;
	default:
	  System.err.println("*** IvyClient *** unhandled msg type "+
	      	    msgtype+" "+msgid+msgarg);
	  break;
	} // switch 
      } // while gardefou
      traceDebug("normally Disconnected from "+
       socket.getInetAddress().getHostName()+":"+socket.getPort());
    } catch (IOException e) {
      traceDebug("abnormally Disconnected from "+
        socket.getInetAddress().getHostName()+":"+socket.getPort());
    }
    bus.disconnect( this );
    bus.removeClient( this );
  }

  private void sendBuffer( String buffer ) {
    buffer += "\n";
    try {
      out.write(buffer.getBytes() );
      out.flush();
    } catch ( IOException e ) {
      /*
       * TODO
       * we should throw an exception here
       */
      System.err.println("IvyClient.sendBuffer.write failed. FIX ME");
    }
  }

  private void send(int type, int id, String arg) {
    sendBuffer(type+" "+id+StartArg+arg);
  }

  private void send(int type, Integer id, int nbsub, REMatch result) {
    String buffer = type+" "+id+StartArg;
    // Start at 1 because group 0 represent entire matching
    for(int sub = 1; sub <= nbsub; sub++) {
      if (result.getSubStartIndex(sub) > -1) {
	buffer += result.toString(sub)+EndArg;
      }
    }
    sendBuffer(buffer);
  }

  private void sendDie() {send(Die,0,"");}
  private void sendDie(String message) {send(Die,0,message);}
  private InetAddress getRemoteAddress() { return socket.getInetAddress(); }
  private void traceDebug(String s){
    if (debug) System.out.println("-->IvyClient<-- "+s);
  }
} // class IvyClient
/* EOF */