Local Java applications running on your z/TPF system can already make requests to existing z/TPF application services through an optimized REST service interface. Java application programmers can call these services without having to know the details of z/TPF programming or how the z/TPF system operates. However, each request to a z/TPF application service generates a new, stateless, ECB that exits when the request is complete. This constraint may limit how your Java applications and z/TPF application services update z/TPF databases.

With stateful services for z/TPF Java applications (APAR PJ45433), customers can create a new type of z/TPF application service that is stateful.  Stateful services allow a Java application thread to call a series of z/TPF application services that will be handled by a single, stateful, ECB.

Because a single ECB handles all of the stateful services for given Java thread, the stateful ECB can hold resources (record holds, open z/TPFDF subfiles, open transaction scopes, etc.) across stateful service calls on behalf of the calling Java thread.
For example, a Java application thread may call a series of stateful services to find and hold records, open and read z/TPFDF subfiles, and open transaction scopes.  After completing those stateful service requests, the Java application thread may execute Java business logic based on the returned data.  Finally, based on the results of the business logic, the Java
application thread may call another set of stateful services to file and unhold records, update and close z/TPFDF subfiles, and commit transaction scopes.

Sample applications will soon be available on the on the TPF Family Products download page, and once the downloads server change is complete.

For more information, see PJ45433 and the IBM z/TPF Knowledge Center.