This topic provides a generic description of what happens when
a Branch Transformation Toolkit application needs to perform one or more activities
in the business logic tier.
- The application presentation layer creates a WSIF request message and
sends it to the application logic layer through a WSIF Access action, or calls
a parameterized EJB method directly or through the EJB Access action.
- As a process engine starts the process, the ProcessStarter of the Abstract
layer starts automatically.
- The Abstract Layer retrieves the session data (session ID and sub-session
ID if used) from the request message or from the work area.
- The Abstract Layer creates the process CHA context and uses a request
mapper to map the data in the request message or method call to the context.
- The Abstract Layer chains the process context to the session context in
the CHA hierarchy. The exception is a login process, which chains the process
context to a specified context in the hierarchy.
- The Abstract Layer caches the contexts to improve performance.
- The process engine proceeds through the activities in the process flow.
- At the end of a process flow, the ProcessTerminator of the Abstract Layer
consults the MapList attribute to determine which data goes in response and
uses response mappers to format the data. The ProcessTerminator then places
the formatted data into the response message.
- When the process engine has completed the flow, the Abstract Layer cleans
up after the process. The Abstract Layer clears caches and removes the process
context from the context hierarchy.
- The application logic layer returns the response message to the application
presentation layer.
For more details and the variations that can occur within the process,
see the descriptions of the default processes.