Activity Parameter Nodes

An Activity Parameter Node accepts input to an Activity or provides output from an Activity.

The following example depicts two entry parameters and one output parameter defined for the Activity.

Simple Activity Diagram

To define an Activity Parameter Node for an Activity, follow the steps below:

  1. Right-click on the element and select the Embedded Elements | Add Activity Parameter context menu option.
  2. The Properties dialog displays, which prompts for the Name and other properties of the embedded element.
  3. After closing this dialog, you can further define the new Activity Parameter; right-click on it and select the Advanced | Custom Properties context menu option. The following dialog displays:
    Activity - Parameters Menu2

Similar to characterizing Action Pins, Activity Parameter Nodes also have the isException and isStream options. IsException indicates that a parameter can emit a value at the exclusion of other outputs, usually because of some error. IsStream indicates whether or not a parameter can accept or post values during the execution of the Activity.

The following example uses the above settings:

Activity Parameter Node

OMG UML Specification

The OMG UML specification (UML Superstructure Specification, v2.1.1, p. 338) states:

An activity parameter node is an object node for inputs and outputs to activities.

... Activity parameter nodes are object nodes at the beginning and end of flows that provide a means to accept inputs to an activity and provide outputs from the activity, through the activity parameters.

Activity parameters inherit support for streaming and exceptions from Parameter.