About Message Variables

You can create messages between actors. There are different attributes related to message elements in a sequence diagram.

This page discusses:

Time Observation

When you insert a time observation, it specifies the activation time of a selected message, at a current message point.

Time Constraint

When you insert a time constraint, it specifies the maximum and/or the minimum time value of the activation of a current message point from a different time observation.

Duration Observation

When you insert a duration observation, it specifies the duration time of a message. It can be used to specify the maximum and minimum time values.

Duration Constraint

When you insert a duration constraint, it specifies the maximum and/or minimum duration time between two messages or between two message points of the same actor.

Notes:
  • A maximum and/or a minimum duration time can be specified for delayed messages.

  • A duration constraint is linked to two messages or two message points between the same lifelines or activations.

Self Message

When you create a self message, it creates a recursive call or a message to the internal component of an actor that is not displayed in a selected sequence diagram.