Timing Diagram

A timing diagram is a specific type of interaction diagram, where the focus is on timing constraints. It is used to explore the behaviors of objects throughout a given period of time.

Diagram Model

Name

Graphical Representation

Description

Lifeline

 ../../../_images/timing-lifeline.png

The lifeline represents an individual participant in the interaction. It is aligned horizontally and read from left to right.

States

 ../../../_images/timing-timeline.png

States are represented by a state lifeline, which shows the change of state of an item over time. Optionally, the reasons/events for a state change can be specified.

Values

 ../../../_images/timing-value.png

Values are represented by a value lifeline. In contrast to the state lifeline, many different values can be modelled.

Duration Constraint

 ../../../_images/timing-duration.png

Constraints for a duration can be very useful. Ranges can be specified with .., e.g. {n..m}.

Synchronous Message

 ../../../_images/timing-sync.png

If states and values from different participants have a direct dependency, the transitions can be modelled with synchronous messages.

Asynchronous Message

 ../../../_images/timing-reply.png

If a reaction is not immediate, e.g. if a response is sent by another task or process, use the asynchronous message arrows.

Timing Ruler

 ../../../_images/timing-ruler.png

The timing ruler is optional, but recommended. The appearance of the ruler can be adapted to the diagram, it may have gaps or variables like t and t+1.

Example

../../../_images/timing.drawio.png