Specification of Reactive Hardware/Software Systems - Electronic ...

184 Modelling of Concurrent Reactive Behaviour
The following list of corresponding statement pairs identifies the receiver of a message
by a:
1. Message name:
ch!messagename
ch?messagename
This pair describes autistic communication.
2. Message name and a guard:
ch!messagename
§ E ch?messagename
The guard expression E must be true for a rendezvous. Notice that the complete
receive statement including the guard will not be executed if the guard is false.
3. Message name and receiver identifier:
ch!messagename(id¥¡ ¡ ¡ )
ch?messagename(id¥¡ ¡ ¡ ¡ id myId)
The identifier id is passed as a parameter of the message. The complete receive
statement will not be executed if the reception condition expression id=myId is
false, where myId is the identifier of the receiver.
4. Message name, guard and receiver identifier.
ch!messagename(id¥¡ ¡ ¡ )
§ E ch?messagename(id¥¡ ¡ ¡ ¡ id myId)
This is a combination of cases 2 and 3.
5. Message name and group identifier:
ch!messagename(groupId¥¡ ¡ ¡ )
ch?messagename(groupId¥¡ ¡ ¡ ¡ groupId myGroupId)
This construct shows the use of a user defined group identifier. Nondeterministically
one object of the members of the group connected to the channel
will accept the message.
6. Message name, guard and group identifier:
ch!messagename(groupId¥¡ ¡ ¡ )
§ E ch?messagename(groupId¥¡ ¡ ¡ ¡ groupId myGroupId)
This is a combination of case 2 and 5.