2 Developing Converged Applications

2.1 Overview of Converged Applications

In a converged application, SIP protocol functionality is combined with HTTP or Java EE components to provide a unified communication service. For example, an online push-to-talk application might enable a customer to initiate a voice call to ask questions about products in their shopping cart. The SIP session initiated for the call is associated with the customer's HTTP session, which enables the employee answering the call to view customer's shopping cart contents or purchasing history.

You must package converged applications that utilize Java EE components (such as EJBs) into an application archive (.EAR file). Converged applications that use SIP and HTTP protocols must be packaged in a single SAR or WAR file containing both a sip.xml and a web.xml deployment descriptor file.You can optionally package the SIP and HTTP Servlets of a converged application into separate SAR and WAR components within a single EAR file.

The HTTP and SIP sessions used in a converged application can be accessed programmatically through a common application session object. The SIP Servlet API also helps you associate HTTP sessions with an application session.

2.2 Assembling and Packaging a Converged Application

The SIP Servlet specification fully describes the requirements and restrictions for assembling converged applications. The following statements summarize the information in the SIP Servlet specification:

• Use the standard SIP Servlet directory structure for converged applications.

• Store all SIP Servlet files under the WEB-INF subdirectory; this ensures that the files are not served up as static files by an HTTP Servlet.

• Include deployment descriptors for both the HTTP and SIP components of your application. This means that both sip.xml and web.xml descriptors are required. A weblogic.xml deployment descriptor may also be included to configure Servlet functionality in the Oracle WebLogic Server SIP Container container.

• Observe the following restrictions on deployment descriptor elements:

  • The distributable tag must be present in both sip.xml and web.xml, or it must be omitted entirely.

  • context-param elements are shared for a given converged application. If you define the same context-param element in sip.xml and in web.xml, the parameter must have the same value in each definition.

  • If either the display-name or icons element is required, the element must be defined in both sip.xml and web.xml, and it must be configured with the same value in each location.

2.3 Working with SIP and HTTP Sessions

As shown in Figure 2-1, each converged application deployed to the Oracle WebLogic Server SIP Container container has a unique SipApplicationSession, which can contain one or more SipSession and ConvergedHttpSession objects.

Figure 2-1 Sessions in a Converged Application

Description of "Figure 2-1 Sessions in a Converged Application"

The API provided by javax.servlet.SipApplicationSession enables you to iterate through all available sessions in a given SipApplicationSession. It also provides methods to encode a URL with the unique application session when developing converged applications.

In prior releases, Oracle WebLogic Server SIP Container extended the basic SIP Servlet API to provide methods for:

• Creating new HTTP sessions from a SIP Servlet

• Adding and removing HTTP sessions from SipApplicationSession

• Obtaining SipApplicationSession objects using either the call ID or session ID

• Encoding HTTP URLs with session IDs from within a SIP Servlet

This functionality is now provided directly as part of the SIP Servlet API version 1.1, and the proprietary API (com.bea.wcp.util.Sessions) is now deprecated. Table 2-0 lists the SIP Servlet APIs to use in place of now deprecated methods. See the SIP Servlet v1.1 API JavaDoc for more information.

final SipApplicationSession appSession = ...;
WlssSipApplicationSession wlssAppSession = (WlssSipApplicationSession) appSession;
wlssAppSession.doAction(new WlssAction() {
       public Object run() throws Exception {
         // Add all business logic here.
         appSession.setAttribute("counter", latestCounterValue);
         sipSession.setAttribute("currentState", latestAppState);
         // The SIP container ensures that the run method is invoked
         // while the application session is locked.
         return null;
       }
});

SipApplicationSession sas1 = req.getSipApplicationSession(); // SipApplicationSession1 is already locked by the container
  // Obtain another SipApplicationSession to schedule work on it
  WlssSipApplicationSession wlssSipAppSession = SipSessionsUtil.getApplicationSessionById(conferenceAppSessionId);
  // The work is done on the application session asynchronously
  appSession.doAsynchronousAction(new WlssAsynchronousAction() {
    Serializable run(SipApplicationSession appSession) {
      // Add all business logic here.
      int counter = appSession.getAttribute("counter");
      ++ counter;
      appSession.setAttribute("counter", counter);
      return null;
    }
});

2.4 Using the Converged Application Example

Oracle WebLogic Server SIP Container includes a sample converged application that uses the com.bea.wcp.util.Sessions API. All source code, deployment descriptors, and build files for the example can be installed in WEBLOGIC_HOME\samples \sipserver\examples\src\convergence. See the readme.html file in the example directory for instructions about how to build and run the example.