Object Oriented Programming using Java - Introduction

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Object Oriented Programming using Java-
Introduction
Department of Computer and Information
Science,School of Science, IUPUI
Dale Roberts, Lecturer Computer Science,
IUPUI E-mail droberts_at_cs.iupui.edu
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Software Orientation over Time

• 1960s, 1970s Process-Orientation Process
  models Data Flow Diagrams,
• Flow Charts
• 1980s Data-Orientation Data models
  Entity-Relationship (ER) Diagrams
• 1990s Object-Orientation Object models
  Class Diagrams, Event Diagrams
• 2000s Unified Modeling Language an attempt
  to standardize all the models into a single
  standard. Synthesizing models is still maturing.

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Overview

• What are object-oriented (OO) methods?
• OO methods provide a set of techniques for
  analyzing, decomposing, and modularizing software
  system architectures.
• In general, OO methods are characterized by
  structuring the system architecture around
  objects (and classes of objects) rather than the
  actions it performs.
• This contrasts object-oriented programming from
  procedural programming.
• What are the benefits of OO?
• OO enhances key software quality factos of a
  system and its constituent components
• What is the rationale for using OO?
• In general, systems evolve and functionality
  changes, but objects and classes tend to remain
  more stable over time.

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Software Quality Factors

• Object-oriented techniques enhance key external
  and internal software quality factors
• External (visible to end-users)
• Correctness
• Robustness and reliability
• Performance
• Internal (visible to developers)
• Modularity
• Flexibility/Extensibility
• Reusability
• Compatibility (via standard/uniform interfaces)

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OOA, OOD and OOP

• Object-oriented methods may be applied to
  different phases of the software development life
  cycle.
• Analysis, Design, Implementation, etc.
• OO analysis (OOA) is a process of discovery.
• Where a development team models and understands
  the requirements of the system in terms of
  actors.
• OO design (OOD) is a process of invention and
  adaptation
• Where the development team created abstractions
  and mechanisms necessary to meet the systems
  behavioral requirements determined during
  analysis.

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OOA, OOD and OOP (cont.)

• OO programming (OOP) implements an OOD in a
  particular programming language.
• The more consistent the OOD and OOP techniques,
  the easier the implementation
• Because of the wide use of OOD and OOP
  terminology, it is useful to distinguish between
  the two.
• OOD is relatively language independent.
• OOP is language dependent and primarily concerned
  with software implementation details of OOD
  concepts (like class definitions, inheritance and
  polymorphism.)

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Basic Definitions

• Object-Oriented Design
• A method of decomposing software architectures
  based on the objects that every systems or
  subsystem manipulates.
• Rather than the functionality that is meant to be
  delivered.
• Object-Oriented Programming
• The construction of software systems as
  structured collections of Abstract Data Type
  (ADT) implementations plus inheritance and
  dynamic binding (polymorphism).

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Object-Oriented Design Topics

• Object-oriented design concepts include
• Decomposition/Composition
• Abstraction
• Modularity
• Information Hiding (Encapsulation)
• Virtual Machine Hierarchies
• Separating Policy and Mechanism
• Subset Identification and Program Families
• Reusability
• Main purpose of these design concepts is to
  manage software system complexity by improving
  software quality factors.

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Object-Oriented Programming Topics

• Object-oriented programming features include
• Data abstraction, Information Hiding
  (Encapsulation)
• Active (rather than passive) types
• Genericity
• Inheritance and dynamic binding (Polymorphism)
• Assertions and exception handling
• This courses focuses on how these OOP topics
  improve software quality
• Correctness, reusability, extensibility,
  reliability, etc.
• Advanced courses focus on OOD topics
• Factoring, Class Diagrams, Use Cases, Design
  Patterns, etc.

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Acknowledgements

• http//www.cs.wustl.edu/schmidt/PDF/ood-overview4
  .pdf