Messages

A message or sending of a communicative act is a communication from one AgentRole to another that conveys information with the expectation that the receiving AgentRole would react according to the semantics of the communicative act. The specification of the protocol says nothing about the implementation of the processing of the communicative act.
A message sending is shown as a horizontal solid arrow from a thread of interaction of an AgentRole to another thread of interaction of another AgentRole.
Each arrow is labelled with a message label that has the following syntax:
predecessor guard-condition sequence-expression communicative-act argument-list
- predecessor This consists of at most one natural number followed by a slash (/) defining the sequencing of a parallel construct or the number of the input and output parameter.
- guard-conditionThis is a usual UML guard condition, with the semantics, that the message is sent iff the guard is true.
- sequence-expression This is a constraint, especially with n..m which denotes that the message is sent n up to m times.
- communicative-act This is either the name, that is, a string representation with an underlined name, of a concrete communicative act instance, the name of a concrete communicative act instance and its associated communicative act, written as name:communicative-act or only the name of the communicative act, for example, inform.
- argument-listThis is a comma-separated list of arguments enclosed in parentheses.