business applications with object-oriented paradigm (modeling concepts)
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Business Applications with Object-Oriented Paradigm (Modeling Concepts). Professor Chen School of Business Gonzaga University Spokane, WA 99258. PARADIGMS (Definition). A paradigm is a way of viewing things and thinking about things. Traditional vs. New Approach. - PowerPoint PPT PresentationTRANSCRIPT
Dr. Chen - Introduction to Object-Oriented Paradigm TM -1
Business Applications with Object-Oriented
Paradigm (Modeling Concepts)
Professor Chen
School of Business
Gonzaga University
Spokane, WA 99258
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PARADIGMS(Definition)
A paradigm is a way of viewing things and thinking about things.
Paradigm Shift
Traditional vs. New Approach
Functional vs. Object-Oriented
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PARADIGMS SHIFT
In the last two decades (mid 1970’s to the present) popular paradigms have been used:
Process ---> Data ---> O-O
Modeling Modeling Modeling
(DFD) (E/R) (UML etc.)
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OBJECT-ORIENTED METHODOLOGY
The technique of object-oriented (OO) methodology really has emerged only in the last five to six years (early 1990’s).
The O-O methods organize both information and the processing that manipulates the information, according to the real-world objects that the information describes.
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I. OBJECT-ORIENTED CONCEPTS
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What is OBJECT-ORIENTED (OO)?
Object = Data structure + Behavior
(attributes) (operations)
where Behavior is in a single entity.
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What is OBJECT-ORIENTED (OO)?
Object = Data structure + Behavior
(attributes) (operations)
where Behavior is in a single entity.
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Why O-O? (Advantages / Objectives)
Understanding problemsCommunicating with application
expertsModeling enterprisesPreparing documentationDesigning programs and databases
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Definition of O-O vs. Conventional Programming
O-O organizing software as a collection of discrete objects that incorporate both data structure and behavior.
Conventional programming: data structure and behavior are only loosely connected.
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Characteristics of Objects:
Identity Classification (Abstraction) Polymorphism Inheritance
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Characteristics of Objects:
Identity Classification (Abstraction) Polymorphism Inheritance
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Characteristics of Objects: Identity:
This means that data is quantified into discrete, distinguished entities called objects
Can be either concrete or conceptual Classification (abstraction):
Means that objects with the same data structure (attributes) and behavior (operations) are grouped into a class
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Characteristics of Objects (Conti.): Polymorphism:
Means that the same operation (e.g., dial) may behave differently on different classes
A specific implementation of an operation by a certain class is called a method
Because an O-O operation is polymorphic, it may have more than one method implementing it
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Characteristics of Objects (Conti.): Inheritance:
Is the sharing of attributes and operations among classes based on a hierarchical relationship
A class can be defined broadly and then refined into successively finer subclasses. Each subclass incorporates, or inherits all of the properties of its superclass and adds its own unique properties
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Objects vs. Classes
Objects Definition: An
object is a concept, abstraction, or thing with crisp boundaries and meaning for the problem at hand.
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Objects vs. Classes (Conti.) Purpose: Objects promote understanding
of the real world and provide a practical basis for computer implementation.
All objects have identity and are distinguishable, and therefore, decomposition of a problem into objects depends on judgment and the nature of the problem.
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Objects vs. Classes (Conti.)Classes Definition: An object class describes a group of objects
with similar properties (attributes), common behavior (operations), common relationships to other objects, and common semantics.
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The abbreviation class is often used instead of object class. The objects in a class share a
common semantic purpose, above and beyond the requirement of common attributes
and behavior.
Objects -----------------------------> Classes Abstract to (Specific) (General) Instances *attributes *operations
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The abbreviation class is often used instead of object class. The objects in a class share a common semantic purpose, above and beyond the requirement of common attributes and behavior.
Abstract
(John,Mary ...) to (Person)
Objects -----------------------------> Classes
(Specific) (General)
Instances *attributes
*operations
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WHAT IS O-O DEVELOPMENT?
Systems Development Life Cycle (SDLC): include the phases of analysis, design, implementation, and maintenance.
O-O Development Life Cycle: focuses on identifying and organizing application-domain concepts, rather than their final representation in a programming language.
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Modeling concepts not implementation.
Definition:A model is an abstraction of a reality.
Abstraction is the process of temporarily ignoring underlying details so we can focus on the most important features (or big picture) of the large problem at hand.
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The real payoff comes from addressing front-end conceptual issues, rather than back-end implementation issues.
An O-O development approach encourages software developers to use and think in terms of the application domain through most of the software engineering life cycles. It is only when the inherent concepts of the applications are identified, organized, and understood that the details of data structures and functions can be addressed effectively.
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What is the Methodology?
Methodology is a series of steps with techniques and notations associated with each step.
Concepts Techniques Notations Steps
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Differences from Functional Methodology
O-O Methodology vs. Conventional (Functional) Methodology
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1. Conventional Methodology
primary emphasis is placed on specifying and decomposing system functionality
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Pros and cons (Conventional)
PROS: it seems the most direct way of implementing a desired goal.
CONS: the resulting system can be fragile because if the requirements change, a system based on decomposing functionality may require massive restructuring.
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2. O-O Methodology
Focuses first on identifying objects from the application domain, then fitting procedures around them.
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Pros and Cons (OO) PROS: O-O software holds up better as
requirements evolve, because it is based on the underlying framework of the application domain itself, rather than the ad-hoc functional requirements of a single problem.
CONS: it is a rather indirect way to describe the problem for those user have used conventional techniques.
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OBJECT-ORIENTED THEMES
Abstraction.Encapsulation (Information Hiding)Combining Data and BehaviorSharing / InheritanceEmphasis on Object Structure, Not
ProcedurePolymorphism
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OBJECT-ORIENTED THEMES
Abstraction.Encapsulation (Information Hiding)Combining Data and BehaviorSharing / InheritanceEmphasis on Object Structure, Not
ProcedurePolymorphism
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1. Abstraction
Concealing irrelevant details from the user.Abstraction is the process of temporarily
ignoring underlying details so we can focus on the big picture of the large problem at hand
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Focusing on the essential, inherent aspects of an entity and ignoring its accidental properties -- in systems development, this means focusing on what an object is and does, before deciding how it should be implemented.
Advantage: preserving the freedom to make decisions as long as possible by avoiding premature commitments to details.
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2. Encapsulation
Information hiding: the process of designing functions, procedures, or classes as “black boxes.” Therefore, to use a function, procedure, or class, a designer does not need to know the box’s inner workings
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Preventing a program from becoming so interdependent that a small change has massive ripple effects. The Implementation of an object can be changed without affecting the applications that use it - reusable code.
Encapsulation is not unique to O-O languages but the ability to combine data structure and behavior in a single entity makes encapsulation cleaner and more powerful than is conventional languages that separate data structure and behavior.
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3. Combining Data and Behavior
Conventional procedural O-O Approach
approach
*data structure hierarchy class hierarchy
*procedure hierarchy
Polymorphism
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3. Combining Data and Behavior
Conventional procedural O-O Approach
approach
*data structure hierarchy class hierarchy
*procedure hierarchy
Polymorphism
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4. Inheritance/ Sharing O-O techniques promote sharing at several different
levels. Inheritance of both data structure and behavior allows
common structures to be shared among several similar subclasses without redundancy.
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PROS:The sharing code using inheritance is one of the main
advantages of O-O language.More important than savings in code is the conceptual
clarity from recognizing that different operations are all really the same thing -- this reduces the number of distinct cases that must be understood and analyzed.
O-O development not only allows information to be shared within an application, but also offers the prospect of reusing design and code on future projects.
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5. Emphasis on Object Structure, Not Procedure
Structure
Object-oriented technology stresses specifying what an object is, rather than how it is used.
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6. Polymorphism Poly - many; Morphic
- forms Many forms An object (e.g.,
telephone) that is capable of having two or more forms (during the run time) with the same name (e.g., dial).
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Development of Object Technology
OO-A
OO-P
OO-D
C++, JAVA
SmallTalk, etc.
UML
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OBJECT ORIENTATION’S CONTRIBUTIONS
COMPUTER-RELATED AREA OO CONTRIBUTIONS
Programming Language Reduces the number of lines of codeDecreases development timeEnhances code reusabilityMakes code maintenance easierEnhances programmer productivity
Graphical User Interface (GUI) Enhances ability to create easy-to-use interfaceImproves system user-friendlinessMakes it easier to define standards
Databases Supports abstract data typesSupports complex objectsSupports multimedia databases
Design Captures more of the data model’s semanticsRepresents the real world better
Operating Systems Enhances system portability, thus improvinginteroperability
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WHAT’S NEXT?
Unified Modeling Language(UML)
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Conclusion -- Synergy
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OBJECT ORIENTATION’S CONTRIBUTIONS
. . .
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Ready for the Next Run?