Abstract
activities are used as placeholders for operations and events in
the process diagram. You use abstract activities to represent steps
in the process in the early stages of process modelling:
When you have not yet decided which operation to use
in the process
When the service that provides the operation is not yet deployed
Later in the development cycle, you define the abstract activities,
which means to specify the actual service operation to use for the
step. Defining an abstract activity does not disrupt any other part
of the process diagram.
Abstract element
Usage
Activity
Represents any activity that is performed
in the process.
You define Activity elements with any operation
that an available service provides.
If you are representing
activities that are performed by a user or another process, you
can use the User and Subprocess elements. The icons on these elements
indicate their intended purpose. (See the information for the Subprocess and
User elements in this table.)
Event
You define Event elements with any event
type that an available service provides.
Abstract elements are for use at design time only and provide
no run-time functionality.
Similar to abstract activities, use abstract
events to represent an undefined event type that is thrown, received,
caught, or used as a start point.
Adding, defining, and deleting abstract activities
Add an abstract activity
to represent a step or event in the process. You can specify a name
and description for abstract activities to indicate the functionality that
is required. At a later time, you define the operation or event
that provides the functionality.
You can change the operation that is defined for an abstract
activity at any time. However, if you change which operation is
defined, any property values that you have specified are removed.
You can also delete abstract activities that you no longer require.
Abstract activities have no behavior at run time. You can test
the execution of other operations in the process diagram while the
abstract activities remain undefined.
Abstract activities are available from the process diagram palette.
Similar to abstract activities, use abstract
events to represent an undefined event type that is thrown, received,
caught, or used as a start point.
Drag the abstract activity
to the process diagram. 
