Monitoring Profile Data with ProfileListener

The IMS Sh interface enables applications to receive automatic notifications when a subscriber's profile data changes. Converged Application Server provides an easy-to-use API for managing profile data subscriptions. A SIP Servlet registers to receive notifications by implementing the com.bea.wcp.profile.ProfileListener interface, which consists of a single update method that is automatically invoked when a change occurs to the profile to which the Servlet is subscribed. Notifications are not sent if that same Servlet modifies the profile information (for example, if a user modifies their own profile data).

Note:

In a replicated environment, Diameter relay nodes always attempt to push notifications directly to the engine tier server that subscribed for profile updates. If that engine tier server is unavailable, another server in the engine tier cluster is chosen to receive the notification. This model succeeds because session information is stored in the SIP data tier, rather than the engine tier.

Prerequisites for Listener Implementations

In order to receive a call back for subscribed profile data, a SIP Servlet must do the following:

Implement com.bea.wcp.profile.ProfileListener.
Create one or more subscriptions using the subscribe method in the com.bea.wcp.profile.ProfileService helper class.
Register itself as a listener using the listener element in sip.xml.

Implementing ProfileListener describes how to implement ProfileListener and use the susbscribe method. In addition to having a valid listener implementation, the Servlet must declare itself as a listener in the sip.xml deployment descriptor file. For example, it must add a listener element declaration similar to:

<listener>
   <listener-class>com.mycompany.MyListenerServlet</listener-class>
</listener>

Implementing ProfileListener

Actual subscriptions are managed using the subscribe method of the com.bea.wcp.profile.ProfileService helper class. The subscribe method requires that you supply the current SipApplicationSession and the key for the profile data document you want to monitor. See "Creating a Document Selector Key for Application-Managed Profile Data" for more information.

Applications can cancel subscriptions by calling ProfileSubscription.cancel(). Also, pending subscriptions for an application are automatically cancelled if the application session is terminated.

Example 2-2 shows sample code for a Servlet that implements the ProfileListener interface.

Example 2-2 Sample Servlet Implementing ProfileListener Interface

package demo;
    import com.bea.wcp.profile.*;
    import javax.servlet.sip.SipServletRequest;
    import javax.servlet.sip.SipServlet;
    import org.w3c.dom.Document;
    import java.io.IOException;
    public class MyServlet extends SipServlet implements ProfileListener {
      private ProfileService psvc;
      public void init() {
        psvc = (ProfileService)
        getServletContext().getAttribute(ProfileService.PROFILE_SERVICE);
      }
      protected void doInvite(SipServletRequest req) throws IOException {
        String docSel = "sh://" + req.getTo() + "/IMSUserState/";
        // Subscribe to profile data.
        psvc.subscribe(req.getApplicationSession(), docSel, null);
      }
      public void update(ProfileSubscription ps, Document document) {
        System.out.println("IMSUserState updated: " + ps.getDocumentSelector());
      }
    }