This page explains the structure and the semantics of the Interaction class.

Interaction tree

An interaction is composed of interaction fragments and is an interaction fragment itself. The fragments form the body of the interaction.

Constraints

An interaction can be constrained. A nested interaction inherits all constraints of its "parent" interaction. At the time being there are four kinds of constraints.

Forbidden Messages

Each message in the list of forbidden messages may never be communicated. As an exception, a forbidden message may be communicated, if the cut is before an equal message in the interaction body.

Interrupting Messages

An interrupting message leads always to the termination of the scenario.

Considered Messages

The communication of a considered message is a safety violation, if the cut is strict, and to the cancellation of the scenario otherwise.

Ignored Messages

Communication of ignored messages does not change the scenario state.