Tools and Techniques for Requirements Engineering and Management - Requirements Engineering and Management for Software Development Projects - page 184

objects instantiated from the classes. The product is then tested and deployed. This
is in brief how the object oriented software development project is executed.
So, when we come to the requirements management portion of the project, we
need to establish the user requirements as we would in any other software project.
OMT (Object Modeling Technique) was oriented towards modeling the design but
not the requirements and therefore, it is not covered here. OOM is currently using
UML, which is detailed in the following sections for modeling the design as well
as requirements.

13.5 Unified Modeling Language

Unified Modeling Language (UML) is used for modeling requirements and design
of software systems. It began in the object oriented methodology but is currently
used in all types of software development projects. UML was created and is
maintained by the OMG (Object Management Group). Ivar Jacobson, James
Rumbaugh, and Grady Booch are credited to have created UML at Rational
Software (now a part of IBM).
One aspect to remember is that UML is not a software development method-
ology but is meant to model the computer applications. It is more like a language
to describe the system. UML uses the following diagrams to model the software
system:

1. Class Diagrams

2. Use Cases

3. Sequence Diagrams

4. Statecharts

5. Activity Diagrams

6. Component Diagrams

7. Deployment Diagrams

We will discuss each of them in a little greater detail in the below sections.

13.5.1 Class Diagrams

Class diagrams are used to depict the classes in a model. Class diagrams are used
to model high level design (roughly equivalent to SRS). User requirements are
analyzed and classes are abstracted and then modeled using class diagrams. Each
class has attributes (data), methods, and relationships with other classes.
Figure 13.8 depicts the symbols used in class diagrams. Using these symbols, class
diagrams are prepared to model classes in the system. Figure 13.9 depicts a very
simplified class diagram for a procurement system.