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Activity Parameter Nodes


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

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

A UML Activty Diagram example using Sparx Systems Enterprise Architect.

Define an Activity Parameter Node for an Activity

UML Activity Diagram example showing the use of an Parameter nodes on an Activity, in Sparx Systems Enterprise Architect.




Right-click on the element and select the 'New Element | Activity Parameter' option.


The 'Properties' dialog displays, which prompts for the name and other properties of the embedded element.


To further define the new Activity Parameter, select the 'Parameter' tab of the 'Properties' dialog and define:

  • Type
  • Default Value
  • Direction
  • Whether this is a fixed value
  • Multiplicity upper and lower bounds
  • Whether to allow duplicates and
  • Whether multiplicity is ordered

Activity Parameter Nodes also have the 'Exception' and 'Stream' options:

  • Exception indicates that a parameter can emit a value at the exclusion of other outputs, usually because of some error
  • Stream indicates whether or not a parameter can accept or post values during the execution of the Activity

Learn more

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.