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.




Define an Activity Parameter Node for an Activity




Right-click on the element and select the New Element | Activity Parameter context menu 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 page of the Properties dialog and define:

Default Value
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.