Example: SIP servlet simple proxy

This is a servlet example of a simple proxy.
Simple proxy

import java.io.IOException;
 import javax.servlet.Servlet;
 import javax.servlet.ServletException;
 import javax.servlet.sip.Proxy;
 import javax.servlet.sip.SipFactory;
 import javax.servlet.sip.SipServlet;
 import javax.servlet.sip.SipServletRequest;
 import javax.servlet.sip.SipServletResponse;
 import javax.servlet.sip.SipSession;
 import javax.servlet.sip.SipURI;
 import javax.servlet.sip.URI;

 public class SimpleProxy extends SipServlet implements Servlet {


  final static  private  String   SHUTDOWN_KEY = new String("shutdown");
  final static  private  String   STATE_KEY = new String("state");
  final static  private  int     INVITE_RECEIVED = 1;

  /* (non-Java -doc)
   * @see javax.servlet.sip.SipServlet#SipServlet()
   */
  public SimpleProxy() {
    super();
  }

  /* (non-Java doc)
   * @see javax.servlet.sip.SipServlet#doInvite(javax.servlet.sip.SipServletRequest)
   */
  protected void doInvite(SipServletRequest request) throws ServletException, IOException {

    
//log("SimpleProxy: doInvite: TOP");

    try {
      if (request.isInitial() == true)
      {
        
//  This should cause the sip session to be created. This sample only uses the session on receiving
        
//  a BYE but the Tivoli performance viewer can be used to track the creation of calls by viewing the         
        
//  active session count.
        Integer state = new Integer(INVITE_RECEIVED);
        SipSession session = request.getSession();
        session.setAttribute(STATE_KEY, state);
              log("SimpleProxy: doInvite: setting attribute");

        Proxy proxy = request.getProxy();

        SipFactory sipFactory = (SipFactory) getServletContext().getAttribute(SIP_FACTORY);
            if (sipFactory == null) {
                throw new ServletException("No SipFactory in context");
            }

            String callingNumber = request.getTo().toString();
            if (callingNumber != null)
            {
                String destStr = format_lookup(callingNumber);
                URI dest = sipFactory.createURI(destStr);

                
//log("SimpleProxy: doInvite: Proxying to dest URI = " + dest.toString());

              if (((SipURI)request.getRequestURI()).getTransportParam() != null)
                ((SipURI)dest).setTransportParam(((SipURI)request.getRequestURI()).getTransportParam());

              proxy.setRecordRoute(true);
          proxy.proxyTo(dest);
            }
        else
        {
                
//log("SimpleProxy: doInvite: Request is invalid. Did not contain a To: field.");
          SipServletResponse sipresponse = request.createResponse(400);
          sipresponse.send();
        }
      }
      else
      {
            
//log("SimpleProxy: doInvite: target refresh, let container handle invite");
        super.doInvite(request);
      }
    }
    catch (Exception e){
      e.printStackTrace();
    }
  }

  /* (non-Java doc)
   * @see javax.servlet.sip.SipServlet#doResponse(javax.servlet.sip.SipServletResponse)
   */
  protected void doResponse(SipServletResponse response) throws ServletException, IOException {
     super.doResponse(response);

     
//  Example of using the session object to store session state.
    SipSession session = response.getSession();
    if (session.getAttribute(SHUTDOWN_KEY) != null)
    {
      
//log("SimpleProxy: doResponse: invalidating session");
      session.invalidate();
    }
  }

  /* (non-Java doc)
   * @see javax.servlet.sip.SipServlet#doBye(javax.servlet.sip.SipServletRequest)
   */
  protected void doBye(SipServletRequest request) throws ServletException, IOException {

    SipSession session = request.getSession();
    session.setAttribute(SHUTDOWN_KEY, new Boolean(true));

        
//log("SimpleProxy: doBye: invalidate session when responses is received.");
    super.doBye(request);
  }

  protected String format_lookup(String toFormat){
    int start_index = toFormat.indexOf('<') + 1;
    int end_index = toFormat.indexOf('>');

    if(start_index == 0){
      
//don't worry about it
    }
    if(end_index == -1){
      end_index = toFormat.length();
    }

    return toFormat.substring(start_index, end_index);
  }
}
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