UML22 — TimeObservationAction and DurationObservationAction

TimeObservationAction and DurationObservationAction are described as actions, but are not really actions like the actions of the action chapter. They would never be used when defining a behavior, but are part of a metalanguage to define temporal constraints and to refer to measured times and durations in formulating such constraints. However, these two elements are the only aspects of this language, everything else is left to be defined later (see TimeExpression). Putting these two mechanisms into the specifications unduly constrains any profile that would want to define a notation for expressing temporal constraints. Such a language might not see a need to use the actions described in this chapter. My recommendation is to find a different way of expressing time observations and duration observations in the metamodel. The syntax examples clearly show that they are not meant to be used within an activity as actions. Note that the only way to use these observations is to create a "fake" activity attached to the interaction (e.g., as a nestedClassifier) which contains only this action. A rather convoluted and heavy-weight means of expressing the simple concept of "NOW" (as the point in time when some model element is executed). A simpler mechanism is clearly needed.

Discussion: Fixed as part of the resolution to issue 8894 in UML 2.1 Revised Text: N/A Disposition: Closed, no change