Release 10.1A: OpenEdge Development:
Open Client Introduction and Programming

Session models

ProxyGen supports two session models for 4GL Web services—session-managed and session-free. The session model is determined by how the AppServer is configured and fundamentally determines how an Open Client and AppServer can communicate with one another. (In ProxyGen, you only need to specify the session model for Web services.)

Session models and Open Clients

If the chosen model is session-managed, a given client has a persistent physical connection to the AppServer over which context can be managed. If the chosen model is session-free, a given client has no persistent physical connection to an AppServer for managing context, but a logical connection that associates the client with the application (or Web) service supported by one or more AppServer resources.

For more information on session models and how they affect Open Client applications, see Chapter 1, " Overview." For a complete definition of session models and how they affect the interaction between an AppServer and client, see OpenEdge Application Server: Developing AppServer Applications .

Specifying the session model

In ProxyGen, you only need to specify the session model explicitly for Web services, because ProxyGen generates a different Web service interface definition depending on the session model. (The default Web service session model is session-managed.) For .NET and Java Open Clients you do not need to specify the session model because the generated proxy is identical for both session models. It is the responsibility of the Open Client application to specify the session model as a run-time session property for connection to an AppServer (session-managed) or application service (session-free).

The session model is really a property of the application service, and the AppServer enables support for and determines the session model for the application service by the setting of the AppServer operating mode. The state-aware, state-reset, and stateless operating modes each specify support for the session-managed model; the state-free operating mode, alone, specifies support for the session-free model. The entire application, including the client and application service, must be programmed differently depending on the session model, which affects your choice of object types used to define the Open Client interface. For more information, see OpenEdge Application Server: Developing AppServer Applications .