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

3.6 Practical Use of Concepts 47
wake?wakeup(Id)
pihs!schedule(PIKeeperId,InitialPosition)
pihp?free(PIKeeperId)
pihp!store(PIKeeperId,PI)
initial method call "Name of the instance method called after process instantiation."
loopForever
instance methods "List of method definitions."
loopForever
acceptProduct;
storeProductInfo;
scheduleServices;
waitTilNextProductArrivalIsSafe;
loopForever
"Enter new product information and physical product."
"Fill a free Product Info Keeper with the accepted PI."
"Notify scheduler of product entrance and initial position."
"Arrange a wake up for a new arrival based
on the appropriate packet distance."
acceptProduct
i?accept(productInfo); "Accept next product information."
piti?productArrived; "Wait until corresponding mailing product arrives."
piti?currentPosition(initialPosition) "Read the initial position of the arrived
product."
storeProductInfo
pihp?free(piKeeperId); "Read identifier of free Product Info Keeper."
pihp!store
"Store product info in free Product Info Keeper."
(piKeeperId,productInfo)
scheduleServices
pihs!schedule
(piKeeperId,initialPosition)
waitTilNextProductArrivalIsSafe
id : ProductInputHandlerId
wake!wakeAt(initialPosition
+productDistance,myId);
wake?wakeup(id ¡ id = myId)
"Send schedule message to Service Scheduler."
"Ask Transporter Image to get woken when
the previous product has been transported
over a productDistance of distance."
(For a proper understanding of this thesis it is not necessary to read the following
explanation of this example. The example gives an impression of the POOSL language.)
Explanation:
The POOSL description consists of the definition of the instance variables, and the
communication channels of the class. The message interface gives a list of all possible
messages on all channels of the class. The initial method call gives the name of
the instance method that is executed when an object starts performing behaviour
for the first time. An instance method is a sort of procedure. Methods can call
each other or themselves recursively so that infinite loops can be created that
model infinite behaviour. The keyword instance methods announces the list of
method definitions. In this case there are five methods: loopForever, acceptProduct,