Systems Analysis and Design

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Systems Analysis and Design ISQA 420 Summer
2001 Analysis Design of System
Behavior Part 2 Object Oriented
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System Behavior Traditional vs.
Object-Oriented o Traditional systems design is
based on programs acting on data, where the data
and programs are separate. o This leads to
separate models for data and behavior.
o Object-oriented systems design is based on
objects employing methods to manage their own
data. o This leads to a unified model...
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Reviewing, and extending, our list
of object-oriented terms and concepts
o encapsulation o message
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System behavior an OO implemen- tation
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Reviewing, and extending, our list
of object-oriented terms and concepts
o encapsulation o message o public (service)
method o private method
o inheritance o overriding o polymorphism
object boundary
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Inheritance polymorphism
For an instance of Subclass 2, its version of
Method B overrides the superclass version
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Overview of the process o Write use cases that
describe the essential business activities
(events) in which the system must play a role.
(Review Chpt 9 vignette Sec 9.1.) o Analyze
use cases (and other sources) to develop an
object relationship model. o Analyze use cases
to identify system behaviors. o Define a method
for each system behavior and assign that method
to a specific class in the ORM (see Table 10.5
and Figure 10.16). o Write comprehensive class
specifications (Table 10.6). o Write formal
use cases (Table 10.7).