private FromHeader getFromHeader() throws IOException {

    if (fromHeader != null) {
      return fromHeader;
    }

    try {
      SipURI fromURI =
          (SipURI)
              addressFactory.createURI("sip:" + proxyCredentials.getUserName() + "@" + registrar);

      fromURI.setTransportParam(sipProvider.getListeningPoint().getTransport());

      fromURI.setPort(sipProvider.getListeningPoint().getPort());

      Address fromAddress = addressFactory.createAddress(fromURI);

      fromAddress.setDisplayName(proxyCredentials.getUserDisplay());

      fromHeader = headerFactory.createFromHeader(fromAddress, Integer.toString(hashCode()));

    } catch (ParseException e) {
      throw new IOException(
          "A ParseException occurred while creating From Header! " + e.getMessage());
    }

    return fromHeader;
  }
  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());
    }
  }
  private ContactHeader getRegistrationContactHeader() throws IOException {
    if (contactHeader != null) {
      return contactHeader;
    }

    try {
      SipURI contactURI =
          (SipURI)
              addressFactory.createURI(
                  "sip:" + proxyCredentials.getUserName() + "@" + proxyCredentials.getHost());

      contactURI.setTransportParam(sipProvider.getListeningPoint().getTransport());
      contactURI.setPort(sipProvider.getListeningPoint().getPort());
      Address contactAddress = addressFactory.createAddress(contactURI);
      contactAddress.setDisplayName(proxyCredentials.getUserDisplay());
      contactHeader = headerFactory.createContactHeader(contactAddress);
      return contactHeader;
    } catch (ParseException e) {
      throw new IOException(
          "A ParseException occurred while creating From Header! " + " " + e.getMessage());
    }
  }
  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;
  }