Process Execution
168 iPlanet Integration Server • Process System Guide • August 200 1
Activity Execution
As a general rule, activity execution consists of taking each activity through the
series of states described in “Activity States” on page 162. In each state, the engine
performs a number of operations before the activity transitions to the next state. As
each state transition takes place, the new state is written into memory and logged
in the state database tables. The engine activates any timer controls referenced by
the new state and executes one or more activity methods that may be defined for
that state in the process definition, as shown in Figure 6-1 on page 164. When
executing activity methods, the engine applies the process attribute locks specified
for those methods in their respective attribute access lists, as defined in the process
definition.
Despite these general rules, activity execution also depends to some degree on the
type of activity being executed. The four types of activities that require work to be
performed—Offered, Queued, Subprocess, and Automatic—are all executed
somewhat differently by an iIS process engine. Execution of each activity type is
discussed separately below.

Offered Activities

Transition to READY State When the trigger conditions are met, the engine
performs any work specified in the Ready method (if one exists in the process
definition) and places the activity in a READY state.
READY State Handling When an Offered activity is placed in a READY state,
the engine offers the activity to sessions (that is, offers it to clients) based on the
activity’s assignment rules.
During assignment, the engine searches for eligible sessions. The engine offers the
activity to sessions based on the activity’s assignment rules (for example, to each
session for which the session’s user profile matches at least one of the activity’s
assignment rules). The engine continues assignment until all active sessions have
been examined.
When an Offered activity is assigned to a session, it is placed on an activity list
maintained by the engine for that session—the session activity list.