Login | Register
My pages Projects Community openCollabNet

20.9.  Event

An event is an observable occurrence. In the UML metamodel it is a child of ModelElement.

There are a number of different types of events that are children of event within the UML metamodel.

  • CallEvent. Associated with an operation of a class, this event is caused by a call to the given operation. The expected effect is that the steps of the operation will be executed.

  • SignalEvent. Associated with a signal, this event is caused by the signal being raised.

  • TimeEvent. An event cause by expiration of a timing deadline.

  • ChangeEvent. An event caused by a particular expression (of attributes and associations) becoming true.

An event is represented by its name.

20.9.1.  Event Details Tabs

The details tabs that are active for events are as follows.

ToDoItem

Standard tab.

Properties

See Section 20.9.2, “ Event Property Toolbar and Section 20.9.3, “ Property Fields For Event below.

Documentation

Standard tab.

Stereotype

Standard tab. In the UML metamodel, an Event has the following standard stereotypes defined.

  • create (for a CallEvent only). Create is a stereotyped call event denoting that the instance receiving that event has just been created. For state machines, it triggers the initial transition at the topmost level of the state machine (and is the only kind of trigger that may be applied to an initial transition).

  • destroy (for a CallEvent only). Destroy is a stereotyped call event denoting that the instance receiving the event is being destroyed.

Tagged Values

Standard tab. In the UML metamodel, an Event has no standard tagged values defined.

20.9.2.  Event Property Toolbar

Go up

Navigate up through the composition structure.

New Stereotype

This creates a new Stereotype (see Section 16.6, “ Stereotype) for the selected event, navigating immediately to the properties tab for that stereotype.

New parameter

This creates a new parameter for the event operation as the current parameter, navigating immediately to the properties tab for that parameter (see Section 18.9, “ Parameter).

Delete

This deletes the event from the model.

20.9.3.  Property Fields For Event

Name

Text box. The name of the event. By convention event names start with a lower case letter and use bumpy caps to divide words within the name in the same way as operations.

[Note]Note

ArgoUML does not enforce this naming convention.

[Tip]Tip

For call events it makes sense to use the name of the associated operation. For signal events it make sense to use the name of the signal, prefixed by [sig]. For time events use the time expression, prefixed by [time] and for change events the change expression, prefixed by [change].

Namespace

Text field. Shows the namespace for the event. This is the composition hierarchy.

Parameters

Text area, with entries for all the actual parameter values of the event (see Section 18.9, “ Parameter).

Button 1 double-click on any of the parameters navigates to that parameter, button 2 click brings up a pop up menu with one entry.

  • New Parameter. Create a new parameter and navigate to it.

Transition

This shows the transition caused by the event.

button 1 double-click on the transition navigates to that transition.

Operations

Drop-down selector. Only present for a Call Event. This allows specifying the operation that causes the event when called.

Signal

Text field. Only present for a Signal Event. This allows specifying the signal that causes the event when called.

Button 1 double-click navigates to the selected signal, button 2 gives a pop up menu with two entries.

  • Add.... This opens a dialog box that allows selecting an already existing signal.

  • New Signal. Creates a new Signal, and navigates to it.

When

Double text field. Only present for a Time Event. This allows expressing the time that the event is called.

The first of the two fields is for the body of the expression, and the second one for the language in which it is written.

[Warning]Warning

In ArgoUML V0.20, the properties panel of a change event lacks a field to enter the change expression.