Process Execution
Chapter 6 Managing Process Execution 165

Activity Types

A process definition can include a number of different activity types, each of which
passes through the various activity states in a different fashion. The table below
summarizes the different types of activities. For more information on activities, see
the iIS Process Development Guide.
Process Execution
This section discusses how an engine executes an iIS process definition. Each
process executes through a life cycle consisting of process instance creation,
process instance execution, and process instance termination. Each of the six
activity types—First, Offered, Queued, Subprocess, Automatic, and Last—plays a
specific role in the overall life cycle.
Process instance creation Process creation involves the creation of a First
activity.
Activity type Description
First Specialized activity: the first activity in a process definition.
Automatically placed in COMPLETED state, bypassing the PENDING,
READY, and ACTIVE states.
Offered An activity performed by client applications. Offered to sessions based
on assignment rules and accepted by a client application from its work
list. Passes through all states.
Queued An activity performed by client applications. Placed on a queue and
accepted by a client application. Passes through all states.
Subprocess Represents a separate process executed by an engine. Passes directly
from PENDING to ACTIVE state, bypassing the READY state.
Automatic An activity performed directly by the engine. Not assigned to sessions.
Passes through all states.
Last Specialized activity: the last activity in a process definition. Passes
directly from PENDING to a COMPLETED state, bypassing the
intermediate states.