next up previous
Next: 3.2.4 Reality compliant Modeling Up: 3.2 Steps for optimizing Previous: 3.2.2 New Subclasses instead

3.2.3 Operations instead of "pushbutton" Variables

 

The problem of so-called "pushbutton" variables resulting from the Internet information model still exists in the first version of the object model (see figure 3): Operations on a managed object are triggered by assigning a value to the corresponding attribute. This is unacceptable for a model expressed in a powerful notation because this representation permits clearer semantics by having the concept of methods. We therefore introduce a new method for every value that a "pushbutton" variable can take. An example may illustrate this: The five possible values of the attribute cpuAction from the class Processor lead to the definition of five methods, namely enable(), disable(), lock(), unlock() and shutdown(). The call of the method enable() is now the replacement for the previous value assignment cpuAction:=1. As these five operations are needed by many components, they have been added to the base object class GenericDevice (see figure 4).



Copyright Munich Network Management Team