What does a duration constraint specify?

What does a duration constraint specify?

• A. Specifies a required time interval for a single event occurrence
• B. Specifies a required time interval for a pair of event occurrences
• C. Specifies a guard condition
• D. Specifies a repetition count

Answer: (B)

A duration constraint defines the time elapsed between two events that must occur within a specified interval. It ties the start of one event to the end of another, capturing timing requirements across the two occurrences. This lets you express how long a particular interaction should take, such as requiring a response to arrive within a certain window after a request is sent. For example, you might specify that a reply must come within 2 to 5 seconds after the request. It’s about the gap between two events, not about a single event by itself. This differs from a guard condition, which controls whether a transition can fire based on a boolean predicate, and from a repetition count, which limits how many times something repeats.

A duration constraint defines the time elapsed between two events that must occur within a specified interval. It ties the start of one event to the end of another, capturing timing requirements across the two occurrences. This lets you express how long a particular interaction should take, such as requiring a response to arrive within a certain window after a request is sent. For example, you might specify that a reply must come within 2 to 5 seconds after the request. It’s about the gap between two events, not about a single event by itself. This differs from a guard condition, which controls whether a transition can fire based on a boolean predicate, and from a repetition count, which limits how many times something repeats.