Artifact: Event
 Event |
The specification of an occurrence in space and time; less formally, an occurrence of something to which the system must respond. |
| UML representation: | Class, stereotyped ½event╗. |
| Worker: | Architect |
| Optionality: | Applicable to reactive (event-driven) systems or those which utilize asynchronous messaging. |
| More information: | |
| Input to Activities: | Output from Activities: |
Purpose 
An event is used to identify and capture information about external occurrences that the system is aware of and to which it must respond. Events can also be used to model internal events, especially exceptions.
Properties
|
Property Name |
Brief Description |
UML Representation |
| Name | The name of the event. | attribute |
| Brief Description | A brief description of the role and purpose of the event. | Tagged value, of type "short text". |
| Event type | one of: Signal, Call Event, Time Event, or Change Event | enum |
| Relationships | The generalizations in which the event participates. | generalization relationship |
| Operations | The operations defined by the event. | operation |
| Attributes | The attributes defined by the event. | attributes |
Timing
Some events, specifically those representing the external events and the significant internal events to which the system must respond, are identified early in the elaboration phase. Other events needed to communicate asynchronously within the system are identified in the latter part of the elaboration phase. All events are architecturally significant and should be completely identified by the end of the elaboration phase.
Responsibility
The architect is responsible for all events, ensuring that events are being use appropriately.
Tailoring
Explicitly modeling events is optional. Events should be modeled if it is
essential for events to be defined and handled consistently across the system.
If each developer is allowed to define their own policy for handling events, the
events can be handled within statechart diagrams.
