لطفا منتظر باشید ...
Chapter 4. Use-Case Diagrams
This chapter focuses on use-case diagrams, which depict the
functionality of a system. First, I introduce use-case diagrams and
how they are used. Next, I discuss actors and use cases. Finally, I
go over various relationships relating to actors and use cases. Many
details that were not fleshed out in Chapter 2 are
more fully elaborated here, and throughout the chapter I include
suggestions relating to use-case diagrams.Use-case modeling is a specialized type of structural modeling
concerned with modeling the functionality of a system. You usually
apply use-case modeling during requirements activities to capture
requirements that define what a system should do. Use-case modeling
typically starts early in a project and continues throughout a system
development process. It is usually done as a series of workshops
between users and analysts of a system in which ideas can be explored
and requirements may be fleshed out over time.As a use-case driven process uses use cases to plan and perform
iterations, it is important to understand how use cases are related
to one another, including what use cases have in common, which use
cases are options of other use cases, and which use cases are similar
to each other. Given that every project has limited resources, you
can use this information about use cases to determine how best to
execute a project. Use cases that are common to two or more other use
cases need only be implemented once, and then they can be reused. Use
cases that are options of other use cases may be implemented at a
later time, and use cases that are similar allow us to implement one
use case that may be reused. An understanding of how use cases are
related allows users and analysts to negotiate and reach agreement
concerning the scope and requirements of a system.A use-case diagram may be considered a "table of
contents" for the functional requirements of a
system. The details behind each element on the use case diagram may
be captured in textual form or using other UML modeling techniques.
All the use-case diagrams and their associated details for a specific
system form the functional requirements of the system. However, the
UML does not provide any explicit guidance on how to capture the
textual details, but focuses more on the notation.
