Information Technology Reference
In-Depth Information
representation of needs to a formal model consists of finding a paradigm and
associated concepts enabling us to represent the entities that make sense in relation
to the problem and to identify the links that join them together. The choice of
formalism depends on the ability of concepts to conserve the integrity of the
constituted data and on the language that will be used for the implementation of the
system.
In this approach, the objective is to look for a formalism and notation that are
specific to software development, in order to have a language for the representation
of data that is mastered by the computing designer tasked with the realization at the
same time as being significant for the ergonomist who analyses needs. This
formalism must enable the contextualized user needs to (re)join the formalized data
of information resources; all the while preserving the wealth that is inherent in the
methodological rigor of data collection and analysis.
To satisfy all the characteristics cited, the object-oriented (OO) approach was
chosen. This approach is at the heart of numerous techniques to analyze, design and
implement flexible and robust real-world systems, including essential properties
such as encapsulation, polymorphism, heritage and reusability [BOO 99], [JAC 92].
It enables the building of the conceptual representations of data issued from the real
world and thus allows their implementation [DÉT 94]. The process of object
modeling offers a support to the translation of experimental data, according to an
ontological description of real world entities and their relations. It enables the
structural, dynamic and functional aspects of an activity to be translated [CHA 03].
This model will be completed by the inheritance analyzed by the designer in order to
build the descriptive model of development.
UML (
Unified Modeling Language
) was adopted as an object modeling standard
by the
Object Management Group
(OMG) in 1997. UML enables multiple views of
a system to be represented, with the help of a variety of graphical diagrams such as
the use case diagram, class diagram, sequence diagram or communication diagram.
In so far as the proposed approach is based on the study of use cases, UML is a
particularly well adapted language. Furthermore, works have shown that the use
case model acts as a powerful communication tool between developers and users
[AGA 03]. A class-state diagram gives the dynamic or static structure of a system,
whereas a state diagram gives the dynamic or behavioral nature in terms of state
transitions. As for the sequence and communication diagrams, they are two types of
interaction diagrams. The sequence diagram explicitly shows the sequencing of
messages, and the communication diagram highlights the relations between objects.
Both are useful to develop a dynamic model of a system in terms of interaction
between objects. An interaction diagram is therefore used to show the interaction
patterns between objects for a particular use case. The objects then communicate
with each other by sending messages.
