Didik Dwi h t t p : / / b l o g. e l e k t r o. u m. a c. i d / d i d i k Object Oriented Software...

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h t t p : / / b l o g . e l e k t r o . u m . a c . i d / d i d i k

Object Oriented Software Engineering

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Subbahasan

Paradigma Pengembangan PL Prinsip Dasar Orientasi Objek Konsep Dasar Orientasi Objek


Paradigma Pengembangan PL

Functional CompositionLogic ProgrammingStructured DevelopmentObject Orientation


Functional Composition

A problem is expressed in termed of a set of mathematical functions. e.g. Double(x) = Add(x, x).

An algorithm is not specified.Language such as Miranda, Gofer, Haskell

support this paradigm.Poor execution speed.


Logic Programming

Consists of a problem description only. e.g. Factorial(0) = 1. Factorial(N) = N x Factorial(N -1).

Doesn’t describe how to solve the problem.

Languages Prolog & Lisp support this paradigm.


Structured Development

Also called SASD, SADT & Functional Decomposition.

Breaks the system into processes & decomposes them.

Data independent from programLanguages C, Fortran, Pascal, Cobol,

Basic and a lot more support this paradigm.

By far the most popular paradigm.


Object Orientation

Most recent paradigm.Treats a problem as a collection of

objects.Becoming very popular now.More and more languages support this

paradigm now.


Basic Principles of OO

Object Orientation

Enca

psul

atio

n

Abst

ract

ion

Hier

arch

y

Mod

ular

ity


What is abstraction?

Salesperson

Not saying Which salesperson – just a salesperson in general!!!

Customer Product

Manages Complexity


What is Encapsulation?

Hide implementation from clients Clients depend on interface

Improves Resiliency

How does an object encapsulate?What does it encapsulate?


What is Modularity?

The breaking up of something complex into manageable pieces

Order Processing System

Billing

OrderEntry

OrderFulfillment

Manages Complexity


What is Hierarchy?

Levels of abstraction

Decreasing abstraction

Increasing abstraction

Asset

RealEstate

Savings

BankAccount

Checking Stock

Security

Bond

Elements at the same level of the hierarchy should be at the same level

of abstraction


Hierarchy

chairtable desk "chable"

instances of chair

furniture (superclass)

subclasses of thefurniture superclass


The OO Mindset

problem domain

objects


Basic Concepts of OO

• classes and class hierarchies– instances– inheritance– abstraction and hiding

• objects– attributes– Methods– polymorphism

• Messages• Component• Package• Subsystem• Relationships


Classes

• object-oriented thinking begins with the definition of a class often defined as:– template– pattern– “blueprint” ... describing a collection of similar

items

OO Principle: Abstraction


Representing Classes

A class is represented using a compartmented rectangle

Professor

Professor Clark

a + b = 10


Class Compartments

A class is comprised of three sections The first section contains the class name The second section shows the structure

(attributes) The third section shows the behavior (operations)

ProfessornameempID

create( )save( )delete( )change( )

Class Name

Attributes

Operations


Building a Class

class name

attributes:

operations:

attributes:

operations


Objects

An object is an instance of a classAn object is something that has:

State Behavior Identity

An object is a "black box" which receives and sends messages.


Classes and Objects

A class is an abstract definition of an object It defines the structure and behavior of each

object in the class It serves as a template for creating objects


Classes and Objects

Objects are grouped into classes

Objects Class

Professor Smith

Professor Jones

Professor Mellon

Professor


What is an Attribute?


Methods

A.k.a Operations, ServicesAn executable procedure that is

encapsulated in a class and is designed to operate on one or more data attributes

CourseOffering

addStudent deleteStudentgetStartTimegetEndTime

Class

Operation


What is Polymorphism

The ability to hide many different implementations behind a single interface

Manufacturer A Manufacturer B Manufacturer C

OO Principle:Encapsulation


Messages

sender object

attributes:

operations:

receiver object

attributes:

operations:

message: [receiver, operation, parameters]

message: [sender, return value(s)]


What is a Component?

A non-trivial, nearly independent, and replaceable part of a system

A component may be A source code component A run time components or An executable component

OO Principle: Encapsulation

<<DLL>>ComponentName

Component Interface


What is a Package?

A package is a general purpose mechanism for organizing elements into groups

A model element which can contain other model elements

Package Name

OO Principle:Modularity


What is a Subsystem?

A combination of a package (can contain other model elements) and a class (has behavior)

OO Principles: Encapsulation and Modularity

<<subsystem>>Subsystem Name

InterfaceInterface

RealizationSubsystem


Subsystems and Components

ComponentName

Design Model Implementation Model

<<subsystem>>Component Name

Component Interface

Component Interface

OO Principles: Encapsulation and Modularity


Relationships

Association Aggregation Composition

DependencyGeneralizationRealization


Relationships: Association

Models a semantic connection among classes

Professor UniversityWorks for

Class

Association

Association Name

Professor UniversityEmployerEmployee

Role Names


Relationships: Aggregation

A special form of association that models a whole-part relationship between an aggregate (the whole) and its parts

Hubungan keseluruhan sebagian (wholepart)

Merepresentasikan hubungan “has a/an”


Relationships: Aggregation

Contoh:

Car Body

Whole

Aggregation

Part


Relationships: Composition

A form of aggregation with strong ownership and coincident lifetimes The parts cannot survive the whole/aggregate

Book Chapter

Whole

Aggregation

Part


Multiplicity and Navigation

Multiplicity defines how many objects participate in a relationships

Associations and aggregations are bi-directional by default, but it is often desirable to restrict navigation to one direction

One direction

Bi-direction


Association: Multiplicity

UnspecifiedExactly oneZero or more (many, unlimited)

One or moreZero or oneSpecified rangeMultiple, disjoint ranges

2..4

0..1

1..*

0..*

1

*

2, 4..6


Multiplicity and Navigation

Example

Student Schedule1 0..*

Multiplicity

Navigation


Relationships: Dependency

A relationship between two model elements where a change in one may cause a change in the other

Merepresentasikan hubungan “using”

Client Supplier

Package

ClientPackage SupplierPackage

Client

Class

Dependency relationship


Relationships: Generalization

Defines a hierarchy of abstractions in which a subclass inherits from one or more superclasses Single inheritance Multiple inheritance

Merepresentasikan hubungan “is-a-kind of”


Relationships: Generalization

One class inherits from another

Accountbalancenamenumber

Withdraw()CreateStatement()

Checking

Withdraw()

Savings

GetInterest()Withdraw()

Superclass (parent)

Subclasses

Generalization Relationship

Ancestor

Descendents


Example: Multiple Inheritance

A class can inherit from several other classes

Airplane Helicopter Wolf Horse

FlyingThing Animal

Bird

multipleinheritance


Relationships: Realization

One classifier serves as the contract that the other classifier agrees to carry out

Component

Interface

Use Case Use-Case Realization

Elided form

Class

InterfaceSubsystem

Interface

Canonical form


Tools for OO

Rumbaugh (OMT)Coad-YourdonBoochUML


Strengths of Object Orientation

Facilitates architectural and code reuseModels more closely reflect the real world

More accurately describe corporate data and processes

Decomposed based on natural partitioning Easier to understand and maintain

Stability A small change in requirements does not mean

massive changes in the system under development


Conclusion

Paradigma pengembangan PL: Fungsional, Logic, Structured, dan OO

Prinsip dasar orientasi objek: Abstraksi, enkapsulasi, modularity, dan

hierarkiKonsep dasar orientasi objek:

Kelas dan Objek Messages, Component, Package, Subsystem Relationships

Didik Dwi h t t p : / / b l o g. e l e k t r o. u m. a c. i d / d i d i k Object Oriented Software...

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