private ArrayList getLocalViaHeaders() throws IOException {
    /*
     * We can't keep a cached copy because the callers
     * of this method change the viaHeaders.  In particular
     * a branch may be added which causes INVITES to fail.
     */
    if (viaHeaders != null) {
      return viaHeaders;
    }

    ListeningPoint lp = sipProvider.getListeningPoint();
    viaHeaders = new ArrayList();

    try {
      String addr = lp.getIPAddress();

      ViaHeader viaHeader =
          headerFactory.createViaHeader(addr, lp.getPort(), lp.getTransport(), null);

      viaHeader.setRPort();

      viaHeaders.add(viaHeader);
      return viaHeaders;
    } catch (ParseException e) {
      throw new IOException(
          "A ParseException occurred while creating Via Headers! " + e.getMessage());
    } catch (InvalidArgumentException e) {
      throw new IOException(
          "Unable to create a via header for port " + lp.getPort() + " " + e.getMessage());
    }
  }
  private MaxForwardsHeader getMaxForwardsHeader() throws IOException {
    if (maxForwardsHeader != null) {
      return maxForwardsHeader;
    }

    try {
      maxForwardsHeader = headerFactory.createMaxForwardsHeader(MAX_FORWARDS);
      return maxForwardsHeader;
    } catch (InvalidArgumentException e) {
      throw new IOException(
          "A problem occurred while creating MaxForwardsHeader " + e.getMessage());
    }
  }
  public void unregister() throws IOException {
    if (!isRegistered) {
      return;
    }

    cancelPendingRegistrations();
    isRegistered = false;

    if (this.registerRequest == null) {
      Log.info("Couldn't find the initial register request");
      throw new IOException("Couldn't find the initial register request");
    }

    Request unregisterRequest = (Request) registerRequest.clone();

    try {
      unregisterRequest.getExpires().setExpires(0);
      CSeqHeader cSeqHeader = (CSeqHeader) unregisterRequest.getHeader(CSeqHeader.NAME);
      // [issue 1] - increment registration cseq number
      // reported by - Roberto Tealdi <*****@*****.**>
      cSeqHeader.setSequenceNumber(cSeqHeader.getSequenceNumber() + 1);
    } catch (InvalidArgumentException e) {
      Log.info("Unable to set Expires Header " + e.getMessage());
      return;
    }

    ClientTransaction unregisterTransaction = null;

    try {
      unregisterTransaction = sipProvider.getNewClientTransaction(unregisterRequest);
    } catch (TransactionUnavailableException e) {
      throw new IOException("Unable to create a unregister transaction " + e.getMessage());
    }
    try {
      unregisterTransaction.sendRequest();
    } catch (SipException e) {
      Log.info("Faied to send unregister request " + e.getMessage());
      return;
    }
  }
  private void register() throws IOException {
    Log.info("Registering with " + registrar);
    FromHeader fromHeader = getFromHeader();
    Address fromAddress = fromHeader.getAddress();

    // Request URI
    SipURI requestURI = null;
    try {
      requestURI = addressFactory.createSipURI(null, registrar);

    } catch (ParseException e) {
      throw new IOException("Bad registrar address:" + registrar + " " + e.getMessage());
    }
    // requestURI.setPort(registrarPort);

    try {
      requestURI.setTransportParam(sipProvider.getListeningPoint().getTransport());

    } catch (ParseException e) {
      throw new IOException(
          sipProvider.getListeningPoint().getTransport()
              + " is not a valid transport! "
              + e.getMessage());
    }

    CallIdHeader callIdHeader = sipProvider.getNewCallId();
    CSeqHeader cSeqHeader = null;

    try {
      cSeqHeader = headerFactory.createCSeqHeader(1, Request.REGISTER);
    } catch (ParseException e) {
      // Should never happen
      throw new IOException("Corrupt Sip Stack " + e.getMessage());
    } catch (InvalidArgumentException e) {
      // Should never happen
      throw new IOException("The application is corrupt ");
    }

    ToHeader toHeader = null;
    try {
      String proxyWorkAround = System.getProperty("com.sun.mc.softphone.REGISTRAR_WORKAROUND");

      if (proxyWorkAround != null && proxyWorkAround.toUpperCase().equals("TRUE")) {

        SipURI toURI = (SipURI) (requestURI.clone());
        toURI.setUser(System.getProperty("user.name"));

        toHeader = headerFactory.createToHeader(addressFactory.createAddress(toURI), null);
      } else {
        toHeader = headerFactory.createToHeader(fromAddress, null);
      }
    } catch (ParseException e) {
      throw new IOException(
          "Could not create a To header for address:"
              + fromHeader.getAddress()
              + " "
              + e.getMessage());
    }

    ArrayList viaHeaders = getLocalViaHeaders();
    MaxForwardsHeader maxForwardsHeader = getMaxForwardsHeader();
    Request request = null;

    try {
      request =
          messageFactory.createRequest(
              requestURI,
              Request.REGISTER,
              callIdHeader,
              cSeqHeader,
              fromHeader,
              toHeader,
              viaHeaders,
              maxForwardsHeader);
    } catch (ParseException e) {
      throw new IOException("Could not create the register request! " + e.getMessage());
    }

    ExpiresHeader expHeader = null;

    for (int retry = 0; retry < 2; retry++) {
      try {
        expHeader = headerFactory.createExpiresHeader(expires);
      } catch (InvalidArgumentException e) {
        if (retry == 0) {
          continue;
        }
        throw new IOException(
            "Invalid registrations expiration parameter - " + expires + " " + e.getMessage());
      }
    }

    request.addHeader(expHeader);
    ContactHeader contactHeader = getRegistrationContactHeader();
    request.addHeader(contactHeader);

    try {
      SipURI routeURI =
          (SipURI) addressFactory.createURI("sip:" + proxyCredentials.getProxy() + ";lr");
      RouteHeader routeHeader =
          headerFactory.createRouteHeader(addressFactory.createAddress(routeURI));
      request.addHeader(routeHeader);

    } catch (Exception e) {

      Log.error("Creating registration route error ", e);
    }

    ClientTransaction regTrans = null;
    try {
      regTrans = sipProvider.getNewClientTransaction(request);
    } catch (TransactionUnavailableException e) {
      throw new IOException(
          "Could not create a register transaction!\n"
              + "Check that the Registrar address is correct! "
              + e.getMessage());
    }

    try {
      sipCallId = callIdHeader.getCallId();
      sipServerCallback.addSipListener(sipCallId, this);
      registerRequest = request;
      regTrans.sendRequest();

      Log.debug("Sent register request " + registerRequest);

      if (expires > 0) {
        scheduleReRegistration();
      }
    } catch (Exception e) {
      throw new IOException("Could not send out the register request! " + e.getMessage());
    }

    this.registerRequest = request;
  }
    /**
     * Process a request from a distant contact
     *
     * @param requestEvent the <tt>RequestEvent</tt> containing the newly received request.
     * @return <tt>true</tt> if the specified event has been handled by this processor and shouldn't
     *     be offered to other processors registered for the same method; <tt>false</tt>, otherwise
     */
    @Override
    public boolean processRequest(RequestEvent requestEvent) {
      synchronized (messageProcessors) {
        for (SipMessageProcessor listener : messageProcessors)
          if (!listener.processMessage(requestEvent)) return true;
      }

      // get the content
      String content = null;
      Request req = requestEvent.getRequest();
      try {

        content = new String(req.getRawContent(), getCharset(req));
      } catch (UnsupportedEncodingException ex) {
        if (logger.isDebugEnabled()) logger.debug("failed to convert the message charset");
        content = new String(requestEvent.getRequest().getRawContent());
      }

      // who sent this request ?
      FromHeader fromHeader = (FromHeader) requestEvent.getRequest().getHeader(FromHeader.NAME);

      if (fromHeader == null) {
        logger.error("received a request without a from header");
        return false;
      }

      Contact from =
          opSetPersPresence.resolveContactID(fromHeader.getAddress().getURI().toString());

      ContentTypeHeader ctheader = (ContentTypeHeader) req.getHeader(ContentTypeHeader.NAME);

      String ctype = null;
      String cencoding = null;

      if (ctheader == null) {
        ctype = DEFAULT_MIME_TYPE;
      } else {
        ctype = ctheader.getContentType() + "/" + ctheader.getContentSubType();
        cencoding = ctheader.getParameter("charset");
      }

      if (cencoding == null) cencoding = DEFAULT_MIME_ENCODING;

      Message newMessage = createMessage(content, ctype, cencoding, null);

      if (from == null) {
        if (logger.isDebugEnabled())
          logger.debug(
              "received a message from an unknown contact: "
                  + fromHeader.getAddress().getURI().toString());
        // create the volatile contact
        from = opSetPersPresence.createVolatileContact(fromHeader.getAddress().getURI().toString());
      }

      // answer ok
      try {
        Response ok =
            sipProvider.getMessageFactory().createResponse(Response.OK, requestEvent.getRequest());
        SipStackSharing.getOrCreateServerTransaction(requestEvent).sendResponse(ok);
      } catch (ParseException exc) {
        logger.error("failed to build the response", exc);
      } catch (SipException exc) {
        logger.error("failed to send the response : " + exc.getMessage(), exc);
      } catch (InvalidArgumentException exc) {
        if (logger.isDebugEnabled())
          logger.debug("Invalid argument for createResponse : " + exc.getMessage(), exc);
      }

      // fire an event
      MessageReceivedEvent msgReceivedEvt =
          new MessageReceivedEvent(newMessage, from, System.currentTimeMillis());
      fireMessageEvent(msgReceivedEvt);

      return true;
    }