Weaving Multiple Aspects in Sequence Diagrams - Transactions on Aspect-Oriented Software Development - page 175

Fig. 6. Illustration of the notions of parts

In our approach, the definition of join point will rely on a notion of part of a
bSD . A join point will be defined as a part of the base bSD such that this part
corresponds to the pointcut. To define the notion of correspondence between a
part and a pointcut, in Sect. 3.2, we introduce the notion of isomorphism between
bSD. To define in a rigorous way the notion of join point, we also have to formally
define the notion of part of a bSD. In Sect. 3.1, we propose four definitions for
parts of a bSD , some of which allow the multiple weaving of aspects.

3.1 Notion of Part of a bSD

We propose four definitions of parts of a bSD which allow the definition of four
different types of join points. These definitions of parts will be called: strict
part, general part, safe part and enclosed part . Before introducing formally the
definitions of parts, we use Fig. 6 to give a first intuitive idea of these parts.
Let us imagine we want to detect a message

m 1 followed by a message m 2

from C 2to C 3 in the bSDs in Fig. 6. Firstly, it is clear that the messages m 1

and 1, but it is not obvious that these two

messages form a join point in the other bSDs because there is either a message
which “surrounds”

m 2 form a join point in the bSD M

m 1and m 2(in M 2), or a message between m 1and m 2(in

M 3and M 4).