Please note : This help page is not for the latest version of Enterprise Architect. The latest help can be found here.

Define Parameters

Within the properties of an operation, Activity or Interaction, you can define parameters to control how that object and its subordinate objects behave.

The order or sequence of the parameters in the object properties is reproduced in code. You can set and manage the order using facilities available within the 'Parameter' tab of the object 'Features' dialog.

Access In diagram or Project Browser:

Click on element | Element | Operations (F10) > Operations > Parameters  or

Right-click on element | Features & Properties | Operations > Operations > Parameters

Define the Parameters



See also


Overtype the New Parameter text with the new parameter name.


Click on the drop-down arrow and click on:

  • The required data type of the operation, as defined by the code language (data type)  or
  • <none> for no type (or you can type in a value manually if you prefer), or
  • Select Type and browse for the appropriate operation classifier (you can add a new one if there are no classifiers that suit)

To add new code language data types that can be displayed in this list, see the Data Types topic.

Data Types Select Dialog

Default Value

(Optional) Type a default value for the parameter.


(Optional) Type in the appropriate stereotype name, or click on the button and select one using the Stereotype Selector.


(Optional) Type an alternative name or reference for the parameter.


Click on the drop-down arrow and select the way the parameter is passed to a function:

  • In = By Value
  • InOut = By Reference
  • Out = Passed By Reference, but only the return value is significant
  • Return - Indicates that the parameter is a returned value

Operation Parameters by Reference

Fixed Value

Click on the drop-down arrow and select True, even if the parameter passed by reference.


Click on the Selector button to display the 'Multiplicity' dialog, and specify the multiplicity of the parameter.


Click on the Selector button and type any additional notes on the parameter. These notes are unformatted.

Define Multiplicity



See also

Lower bound

Type a lower limit to the number of elements allowed in the collection.

Upper bound

Type an upper limit to the number of elements allowed in the collection.

Allow Duplicates

Select the checkbox if you want to allow duplicates.

This maps to the UML property 'isUnique', with the value False.

Multiplicity is Ordered

Select the checkbox if you want to indicate that the collection is ordered.


Click on this button to save the changes and close the dialog.


  • To organize parameters into the required sequence, and reorganize the display of information, right-click on the background of the 'Parameter' tab or on a specific parameter and select from the same context menu options as for the 'Operations' panel
  • Set the amount of parameter detail to display in a specific diagram using the 'Show Parameter Detail' drop-down list on the 'Features' tab of the 'Diagram Properties' dialog; the setting applies only to the current diagram, and the default is to show the type only
  • You can set Tagged Values on a parameter, as well as on the parent operation

Learn more