Современные
информационные технологии/3. Программное обеспечение
Zhuaspaev T.A
A.Baitursynov
Kostanai State University, Kazakhstan
GUIDELINES FOR THE
DEVELOPMENT
USE CASE DIAGRAM
Visual
modeling in UML can be represented as a certain process of descent from the
most general and abstract conceptual model to the logical, and then to the
physical model of the relevant information system. To achieve these
goals, first built a model of the use cases that describes the functionality of
the system, that is designed for functional simulation system.
When writing a use case scenarios it is
important to understand that the text of the script should complement or
clarify the use case diagram, but does not replace it completely. Otherwise,
you will lose the dignity of the visual presentation models. Building a use
case diagrams - the first step in the process of object-oriented analysis and
design, which aims - to provide a set of functional requirements for the
behavior of the designed system. Specification of requirements for the
projected system in the form of use case diagrams and additional scenarios can
be a self-model, which is called the UML use-case model and the standard has
its own special name or stereotype << useCaseModel >>.
Use case diagram can serve as a basis for
negotiation with the customer, the functional requirements of the system at an
early design stage. Any use of the base in the following embodiment may be
subjected to partial decomposition to use cases. It is recommended that the
total amount of the actors in the model did not exceed 20, and for this use -
50. Otherwise, the model loses its clarity and possibly replaces one of some
other diagrams.
For the development of use case diagrams
recommended a sequence of actions:
Ø Identify the main or primary and secondary actors.
Ø
Identify the main
purpose of the actors in relation to the system.
Ø
Formulate the basic use
cases that specify the functional requirements of the system.
Ø
Sort uses in descending
order of risk of their implementation.
Ø
Consider all of the
basic use cases in order of risk.
Ø
Scroll to the member
interests, preconditions and post-conditions of the selected use case.
Ø
Write a successful
simulation of the selected use case.
Ø
Define exceptions or
failure in the implementation of a use case scenario.
Ø
Write scripts for all
exceptions.
Ø Identify common use cases and portray their relationship with the base with the stereotype << include >>
Ø
Highlight the use cases
for exceptions and portray their relationship with the base with the stereotype
<< extend >>
Ø Check the chart on the avoidance of duplication of use cases and actors.
Before constructing the chart to document
the flow of events in the system. The flow of events - is the process of data
processing implemented within one or more use cases. Describe flow includes
information about what responsibilities are assigned to the actors, and what -
on the system. It contains:
Ø
a brief description of
the behavior, which is implemented in the form of use;
Ø
preconditions -
conditions that must be met before the use case can be invoked. For example,
such a condition may be the completion of another embodiment of the use, or
whether the user has access rights;
Ø
describes the basic flow
of events that must occur during the execution of the use in the most common
(typical) case. In this case the child uses associated with the base by
inclusion;
Ø
alternative flows of
events describe exceptions. The child uses when designing the chart associated
with the basic attitude of expansion;
Ø
post-conditions -
conditions that must be met after the completion of the use case. For example,
such a condition may be required preservation of calculation results in a
database on a server.
The diagrams do not display features of
the use cases and the internal organization of the system, related to the
specific use of software and hardware. These diagrams are intended primarily
for sharing with the customer to define the functional requirements of the
system. Therefore, to understand (interpret) displayed on the charts and the
customer and the developer must agree.
Literature:
1. Леоненков А.В.
Объектно-ориентированный анализ и проектирование с использованием UML и IBM
Rational Rose – М.: Бином, 2006 – 320 с.: ил.
2. Ларман К. Применение UML и
шаблонов проектирования. 2-е издание.: Пер. с англ. – М.: Издательский дом
“Вильямс”, 2002. – 624 с.: ил.