Thesis full text (PDF) - Politecnico di Milano

them by invoking respectively the create, set, getClasses, and destroy methods. In case a
selection condition is multi-valued, another parameter value indicates if the condition for a
retrieved element should be satisfied for every input value or for at least one. Both conjunctive
and disjunctive expressions are allowed.
u:User
>
c:ClassComponent
query([["Jackie Brown"], ["Horror Parody"])
set("Jackie Brown")
:ClassOfInstance
c1 = getClasses()
destroy()
set("Horror Parody")
:ClassDisjointOfClass
c2 = getClasses()
destroy()
classes
classes = conjunction(c1, c2)
Figure 3.2: Invocation of the Class Component
To exemplify the behavior of the component, figure 3.2 shows the UML sequence diagram
describing the extraction of classes both defining the Jackie Brown object and being disjoint to
the Horror Parody class. The user inserts the values as parameters to the query method through
the user interface. The Class Component object creates a new ClassOfInstance object and
initializes the condition value invoking the set method with Jackie Brown as parameter value.
Then, it calls the getClasses method to get the classes defining Jackie Brown, and it destroys the
selection condition object. The Class Component object creates the ClassDisjointOfClass object,
sets the condition value to Horror Parody, and gets the classes being disjoint to it. Finally, the
object component returns to the user the conjunction of the two result sets.
29