|Previous||UML Classes||Table of Contents||UML Packages||Next|
Observation (from SimpleTime ) on page 463
An observation is a reference to a duration during an execution. It points out the element(s) in the model to observe and
whether the observations are when this model element is entered or when it is exited.
• firstEvent:Boolean[0..2] The value of firstEvent[i] is related to event[i] (where i is 1 or 2). If firstEvent[i] is true,
then the corresponding observation event is the first time instant the execution enters event[i]. If firstEvent[i] is false,
then the corresponding observation event is the time instant the execution exits event[i]. Default value is true applied when
event[i] refers an element that represents only one time instant.
• event:NamedElement [1..2] The observation is determined by the entering or exiting of the event element during execution.
 The multiplicity of firstEvent must be 2 if the multiplicity of event is 2. Otherwise, the multiplicity of firstEvent
if (event->size() = 2) then (firstEvent->size() = 2) else (firstEvent->size() = 0)
A duration observation denotes some interval of time.
A duration observation is often denoted by a straight line attached to a model element. The observation is given a name which
is shown close to the unattached end of the line.