Object-Oriented Design - Java Software Solutions: Foundations of Program Design - page 303

During software design, alternatives need to be considered and
explored. Often, the first attempt at a design is not the best solution.
Fortunately, changes are relatively easy to make during the design stage.
Implementation is the process of writing the source code that will
solve the problem. More precisely, implementation is the act of translating the
design into a particular programming language. Too many programmers focus
on implementation exclusively when actually it should be the least creative of all
development activities. The important decisions should be made when establish-
ing the requirements and creating the design.
Testing is the act of ensuring that a program will solve the intended problem
given all of the constraints under which it must perform. Testing includes run-
ning a program multiple times with various inputs and carefully scrutinizing the
results. But it means far more than that. We revisit the issues related to testing in
Section 7.9.

KEY CONCEPT
The effort put into design is both
crucial and cost-effective.

SELF-REVIEW QUESTIONS (see answers in Appendix N)
SR 7.1

Name the four basic activities that are involved in a software develop-
ment process.

SR 7.2 Who creates/specifies software requirements, the client or the devel-

oper? Discuss.

SR 7.3 Compare and contrast the four basic development activities presented

in this section with the five general problem-solving steps presented in
Section 1.6.

7.2 Identifying Classes and Objects

A fundamental part of object-oriented software design is determining the classes
that will contribute to the program. We have to carefully consider how we want
to represent the various elements that make up the overall solution. These classes
determine the objects that we will manage in the system.
One way to identify potential classes is to identify the objects discussed in
the program requirements. Objects are generally nouns. You literally may want
to scrutinize a problem description, or a functional specification if available, to
identify the nouns found in it. For example, Figure 7.1 shows part of a problem
description with the nouns circled.
Of course, not every noun in the problem specification will cor-
respond to a class in your program. This activity is just a starting
point that allows you to think about the types of objects a program
will manage.

KEY CONCEPT
The nouns in a problem description
may indicate some of the classes and
objects needed in a program.