Activity (dictionary item)

Model Parts, Diagrams, Dictionary Items, and Properties > Dictionary items > Activity (dictionary item)

For automation interface information about an Activity, see Activity (automation interface).

An Activity is a specification of parameterized behavior that is expressed as a flow of execution via a sequencing of subordinate units (whose primitive elements are individual actions).

Create an Activity from an Activity, Actor, Basic Type, Class, Interface, Model, Package, Operation, Type Definition and Use Case – right-click the owning item, point to New, and then click Activity. On a State Diagram, you can create an activity for a State through the Activity button.

Note that when you create an Activity from a Class or Interface, Modeler also creates an Activity Diagram as a child of the new Activity.

Describe the behavior of an Activity, or the parent item of the Activity, through an owned Activity Diagram.

If you want to create an Association between an Activity and a Class, you must do so through an Object Node. For more information, see Showing an association between an activity and a class on a class diagram.

When used on a Class Diagram, an Activity's notation is as follows.

For information about the View Options available for this symbol, see Activity view options - activity diagram and Activity view options - class diagram.

Note that when a Class Diagram shows an association or composite aggregation symbol starting from an Activity, that link symbol represents a Call Behavior Action, Central Buffer, Data Store, Input Pin or Output Pin, rather than an Association dictionary item. For more information, see the following topics:

• Creating a composite aggregation between two activities on a class diagram

• Showing an activity call tree on a class diagram

When you create an Activity Diagram from an Activity, the Activity is linked to the frame that is created on the diagram.

In the Modeler panes, a short-cut symbol

on the Activity's icon indicates that the item is a stub. For more information, see Stubs.

You can specify the Parameters of an Activity through its signature. For more information, see Using an activity signature to specify name and parameters. If an Event's signature is greater than 200,000 characters, the Parameters' Default values are not included in the signature.

The following sections provide information about how an Activity is used in the model. For more information about a property, item, model part or diagram, click it.