Transcript UML11.ppt

Software Engineering
- Mr. Ahmad Al-Ghoul
Learning Objectives
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Explain relationships among objects
and the concept of inheritance
Explain an object relationship diagram
Describe Unified Modeling Language
(UML) tools and techniques, including
use cases and use case diagrams
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Object-Oriented analysis and
design using UML
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Relationships
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Enables objects to communicate and interact as they perform
business functions and transactions required by the system
Relationships describe what objects need to know about each
other
Relationships describe how objects respond to changes in other
objects
Relationship describe the effects of membership in classes,
super-classes, and subclasses
Inheritance enables an object, called a child, to derive one or
more of its attributes from anther object, called a parent
A child object, however, may have additional attributes
The inherited attributes from the parent object do not need to
be repeated in the child object
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Object-Oriented analysis and
design using UML [1]
An inheritance relationship exists between the INSTRUCTOR and
EMPLOYEE objects. The INSTRUCTOR (child) object inherits
characteristics from the EMPLOYEE (parent) class and can have
additional attributes of its own.
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Object-Oriented analysis and
design using UML
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Relationships Among Objects and Classes
Object Relationship Diagram
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After you identify the objects, classes, and
relationships, you are ready to prepare an
object relationship diagram that will provide
an overview of the system
You will use that model as a guide as you
continue to develop additional diagrams and
documentation
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Object-Oriented analysis and design using UML [1]
Object relationship diagram for the fitness center.
Notice that the model shows the objects and how they
interact to perform business functions and transactions
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Object-Oriented analysis and
design using UML
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Object Modeling with the Unified Modeling
Language
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The UML uses a set of symbols to represent
graphically the various components and
relationships within a system
although the UML can be used for business
process modeling and requirements modeling,
it mainly is used to support object-oriented
system analysis and to develop object models
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Object-Oriented analysis and
design using UML
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Use case modeling
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Use Case
A use case represents the steps in a specific
business function or process
 A use case is a complete sequence of related
actions initiated by an actor
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An external entity called an actor, initiates a
use case by requesting the system to perform
a function or process
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Object-Oriented analysis and
design using UML
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An actor is someone or something that is
external to the system, but that is going to
interact with the system.
Actors are represented as stick figures.
Action or event represents by an oval with
a label that describes the action or event
The line from the actor to the use case is
called an association
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Object-Oriented analysis and
design using UML
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Use Case Diagrams
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Applied to analyze functional requirements of
the system
Performed during the analysis phase to help
developers understand functional
requirements of the system without regard for
implementation details
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Object-Oriented analysis and
design using UML
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Use Case Diagrams
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Use case diagrams are created to visualize the
relationships between actors and use cases
A use case diagram is a summary of several related
use cases within a system or subsystem
Use cases represent complete functionality of the
system
To create a use cases, you start reviewing the
information that you gathered during the
requirements modelling phase
Identify the actors and the functions or transactions
they initiate for each use case
Develop a use case description in the form of a table
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Object-Oriented analysis and
design using UML
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Use case description
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A use case description documents the name of the
use case
Names of the actors
A description of the use case
A step by step list of the tasks and actions required
for successful completion
A description of alternative causes of action
Preconditions
Post conditions
assumptions
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Object-Oriented analysis and design using UML [1]
The ADD NEW STUDENT use case description documents the
process used to add a current student into an existing class.
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Object-Oriented analysis and
design using UML
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Steps to create a use case diagram
Identify the system boundary, which is represented
by a rectangle
 Place the use cases on the diagram
 Add the actors
 Show the relationships
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Object-Oriented analysis and
design using UML
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Relationships Between Use Cases
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Use cases may participate in relationships
with other use-cases
Two types
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Extends
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Adds new behaviors or actions to a use case
Include
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One use case references another use case
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Object-Oriented analysis and design using UML [1]
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The figure shows a use
case diagram for an auto
service department which
involves customers, service
writers who prepare works
orders and invoice, and
mechanics who perform
the work.
the customer actor
initiates the use case by
requests service.
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Sequence Summary
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After you identify the objects, classes, and relationship,
you prepare an object relationship diagram that shows
the objects and how they interact to perform business
functions and transactions
Inheritance enables an object, called a child, to derive
one or more of its attributes from anther object, called a
parent
UML techniques include use cases and use case
diagrams
A use case describes a business situation initiated by an
actor, who interacts with the information system
Each use case represents a specific transaction, or
scenario
A use case diagram is a visual summary of related use
cases within a system or subsystem
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Sequence Summary
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In this Sequence we have
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Described how to draw an object relationship
diagram that shows the objects and how they
interact to perform business functions and
transactions
Defined the term inheritance
Explained use case that describes a business
situation initiated by an actor, who interacts
with the information system
Explained use case diagram and described
how to draw it
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Reference
[1] System Analysis and Design, Sixth Edition
Authors: Gary B. Shelly, Thomas J. Cashman and Harry J. Rosenblatt
,
Publisher: SHELLY CASHMAN SEWIES.
[2] system analysis and design, sixth edition
Authors: Kenneth E. Kendall and Julie E. Kendall
Publisher: Prentice Hall
[3] Modern Systems Analysis and Design Third Edition
Authors: Jeffrey A. Hoffer , Joey F. George, Joseph S. Valacich
Publisher: prentice hall
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