How to use TopLink's mapping info at runtime

Question

Can anybody kindly instruct how to do the following:
1) Once the "JavaSource.java" file or the "ProjectDeployment.xml" file is generated by TopLink from a TopLink project, how can it be included and used in a J2EE project at runtime? I understand that this step may be specific to the type of IDE used, let us say WebLogic, WebSphere or JDeveloper9i.
2) Can TopLink generate the file "sessions.xml" automatically or it has to be hard-coded? Does this file have also to be included in a J2EE project under the directory of META-INF at runtime?

Answer 1

Hi John,
Probably the best way I can explain the process of putting a J2EE app with TopLink into production would be to describe the best practices of doing so.
Firstly, I recommend using an IDE to develop your Java source code, although it is possible to generate Java source directly from the Mapping Workbench, this is considered more of a rapid prototyping or quick start process. Once the Java source has been compiled, the Meta-Data (project.xml) can be deployed from the Mapping Workbench.
The next step really depends on the type of application you are creating. Since you are developing a J2EE based application and it will be multi-user, TopLink recommends using a ServerSession architecture. (Consult the documentation for detailed explanations). Configuring the session can be done in a number of ways, the best way would be to use the SessionManager and an external file called sessions.xml. Both the sessions.xml and project.xml must be visible by the J2EE component that will be using it. (Servlet/Session Bean, etc...). This is done through managing your deployment properly using something like an EAR.
The key to getting the application and TopLink working together is the session, and here's a basic example on how you could set this up:
sessions.xml code:
<toplink-configuration>
     <session>
          <name>myProject</name>
          <project-xml>myProject.xml</project-xml>
          <session-type>
               <server-session/>
          </session-type>
          <connection-pool>
               <is-read-connection-pool>false</is-read-connection-pool>
               <name>default</name>
               <max-connections>10</max-connections>
               <min-connections>5</min-connections>
          </connection-pool>
          <enable-logging>true</enable-logging>
     </session>
</toplink-configuration>
Somewhere in your application code, you might have a login method that makes use of the SessionManager to load and create the session:
SessionManager sm = SessionManager.getManager();
          Server serverSession = (Server)sm.getSession("myProject", this.getClass().getClassLoader());
The sessions.xml must be created manually at this point, a future version of the TopLink product will contain an editor which will help out.
Darren Melanson