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Null pointer exception in servlet

 
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Null pointer exception in servlet

nila
post 1 Jul, 2008 - 03:14 AM
Post #1


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Joined: 5 Jan, 2008
Posts: 119

Hi,
I tried to get the status of the extension in a servlet program using the command

CODE


      
    String a =statusevent.getChannel()
    String b=statusevent.getEvent()
      


I have declared status event like

CODE

    private StatusEvent statusevent


please assist me to solve this problem.

Thanks.
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1lacca
post 1 Jul, 2008 - 03:25 AM
Post #2


code.rascal

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We'll need a bit more code.
If you only wrote
CODE

private StatusEvent statusevent;
String a =statusevent.getChannel();
It will naturally throw a null pointer exception, because statusevent does not reference an instance. At least specify the fully qualified name of the StatusEvent class, so we know what are you trying to do.
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nila
post 2 Jul, 2008 - 09:15 PM
Post #3


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Joined: 5 Jan, 2008
Posts: 119

Thanks for your reply.sorry for the delayed response.what i need to do is: I am using asterisk java to make inbound and outbound calls.if i dial a number from my extension and run the following program,it should get the status of the extensions whether it is ringing ,busy,up etc...
but now i am getting the result null.i think i am doing mistake in creating object.my code follows.
CODE

package com.example.servlets;
import java.io.*;
import javax.servlet.*;
import javax.servlet.http.*;
import org.asteriskjava.manager.AuthenticationFailedException;
import org.asteriskjava.manager.ManagerConnection;
import org.asteriskjava.manager.ManagerConnectionFactory;
import org.asteriskjava.manager.TimeoutException;
import org.asteriskjava.manager.action.OriginateAction;
import org.asteriskjava.manager.action.StatusAction;
import org.asteriskjava.manager.response.ManagerResponse;
import org.asteriskjava.manager.action.ManagerAction;
import org.asteriskjava.manager.event.StatusEvent;
import org.asteriskjava.manager.action.ExtensionStateAction;
import org.asteriskjava.manager.event.ExtensionStatusEvent;
import org.asteriskjava.manager.AbstractManagerEventListener;
import org.asteriskjava.live.ChannelStateHistoryEntry;
import org.asteriskjava.live.internal.AsteriskServerImpl;
import org.asteriskjava.manager.ManagerEventListener;
import java.lang.Object;
public class OutboundServlet extends HttpServlet {
    int i;
    String a,b,d;
    private ManagerConnection managerConnection;
    
    public Integer getStatus()
    {
         return status;
          
        
    }
  

  
  public void doGet(HttpServletRequest request,
                    HttpServletResponse response)
      throws ServletException,NullPointerException, IOException {
    
      PrintWriter out = response.getWriter();
  
      
      //pasted from http://asterisk-java.org/development/tutorial.html :-)
    
try {
    
ManagerConnectionFactory factory = new ManagerConnectionFactory(
        
                "localhost", "admin", "amp111"); //

        this.managerConnection = factory.createManagerConnection();

        StatusEvent event;
             ManagerResponse originateResponse;
              
        managerConnection.login();
        managerConnection.sendAction(new StatusAction());
         event=new StatusEvent(5101);
        out.println(event.getState());
        out.println(event.getChannel());
      
         // and finally log off and disconnect
        managerConnection.logoff();
      
out.println("OK");
} catch (Exception e) {
   out.println("NOT OK");
   e.printStackTrace();
}

  }
}

Thanks.
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