Sun Microsystems iPlanet Integration Server 3.0, Руководство по системе управления

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What Does an iIS Process Engine Do?
36 iPlanet Integration Server • Process System Guide • August 2001
What Does an iIS Process Engine Do?
As suggested in “What Is an iIS Process Engine?” on page 27 , an iIS process engine
performs a number of different functions in support of an iIS system. These include
the following.
Managing sessions The engine opens, suspends, and closes sessions. When
opening a session, the engine first validates a user’s logon against an
organizational database. For more information on sessions, see
“Engine Sessions”
on page 158 .
Executing processes The engine creates instances of a process and manages their
execution from start to finish. During each process’ execution, a succession of
activities is performed by applications that have opened sessions with the engine.
The engine manages and tracks these activities through to their final completion.
Registering distributions Process definitions, assignment rule dictionaries, user
profiles, and a validation constitute the process logic components executed by the
engine during process execution. Registration lets you change these components
dynamically as business processes and organizational structures change.
Maintaining an engine history database
The engine can maintain a history of
each process execution, writing all changes of state to an engine history database.
The history can include changes of state in activities, process attributes, timers, and
so on.
While process execution is the key engine function, managing sessions, registering
definitions, and maintaining the history database are all necessary to support
process execution.
To provide these functions, the iIS engine is internally structured around a number
of manager objects, as shown in
Figure 1-5 :
• Session Manager—maintains engine sessions
• Process Manager—works closely with the Timer Manager and Access Manger
to execute iIS process definitions
• Registration Manager—keeps track of the names and versions of registered
process definitions
• History Manager—writes current state and history log information to the
engine database.