LarmanChap1

8/7/2019 LarmanChap1

1/19

NJIT

Object Oriented Analysis and

Design

Chapter 1

Applying UML and Patterns

Craig Larman


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NJIT

Applying UML and Patterns in

OOA/OOD

What is a good object

design?


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Applying UML UML is just a standard diagramming

notation. It is just a tool, not a skill that is

valuable in itself. Knowing UML helps youcommunicate with others in creating

software, but the real work in this course is

learning Object-Oriented Analysis andDesign, not how to draw diagrams.


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Assigning Responsibilities The most important skill in Object-

Oriented Analysis and Design is assigning

responsibilities to objects. Thatdetermines how objects interact and what

classes should perform what operations.


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Design Patterns Certain tried-and-true solutions to design

problems have been expressed as

principles of best practice, often in theform ofDesign Patterns.

A Design Pattern is a named problem

solution formula that apply excellentdesign principles.


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Requirements AnalysisAll Software Analysis and Design is

preceded by the analysis of requirements.

One of the basic principles of good designis to defer decisions as long as possible.The more you know before you make adesign decision, the more likely it will be

that the decision is a good one.

TFCL: Think First, Code Later!


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Use Cases Writing Use Cases is not a specifically

Object Oriented practice. But it is a best

practice for elaborating and understandingrequirements. So we will study Use

Cases.


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The Unified ProcessA standardized approach to analysis and

design helps to ensure that all necessary

tasks are understood and completed insoftware development.

This text, and the course, will focus on the

Unified Process developed at RationalSoftware by Ivar Jacobsen, Grady Boch,

Jim Rumbaugh, and others.


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Other Necessary Skills Requirements Analysis, Object-Oriented

Analysis and Object-Oriented Design are

not a complete toolkit for a softwaredeveloper. There are many other skills

necessary in Software development,

including programming. This course onlycovers a subset of the necessary skills.


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Assigning Responsibilities The Desert Island Skill in OOD is

assigning responsibilities to objects.

Nine fundamental principles for doing this

will be presented as the GRASP patterns.

GRASP is an acronym forGeneral

Responsibility Assignment Patterns.


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NJIT

What is Analysis?

(Class-answer the question)


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AnalysisAnalysis is a broad term. In Software

development, we are primarily concerned

with two forms of analysis. Requirements Analysis is discovering the

requirements that a system must meet inorder to be successful.

Object Analysis is investigating the objectin a domain to discover informationimportant to meet the requirements.


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NJIT

What is Design?

(Class-answer the question)


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Design

Design emphasizes a conceptual solution

that fulfills the requirements. A design is

not an implementation, although a gooddesign can be implemented when it is

complete.

There are subsets of design, includingarchitectural design, object design, and

database design.


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Analysis and Design

Analysis

do the right thingDesign

Do th

e th

ing righ

t


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What is Object Oriented

Analysis?

The emphasis is on finding and describing

the objects (or concepts) in the problem

domain.

In a Library Information System, some of

the concepts include Book, Library, and

Patron.


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What is Object Oriented

Design?

The emphasis is defining software objects

and how they collaborate to fulfill the

requirements.

In a Library Information System, a Book

software object may have a title attribute

and a getChaptermethod.


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Implementation

During Implementation, orObject-Oriented

Programming, design objects are

implemented, such as a book class inJava.

Implementation is also known as Coding

orConstruction.


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Example Tasks

Define Use Cases

Define a Domain Model

Define Interaction Diagrams

Define Design Class Diagrams

Documents

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