09-Building-an-Application-V1 (1).ppt

7/27/2019 09-Building-an-Application-V1 (1).ppt

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IS Software Foundations

Building an Application

Belief in oneself is one of the most importantbricks in building any successful venture.Lydia M Child


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2Object Oriented Application Development

Overview

Objective

Apply concepts learnt so far to build a consoleapplication

Content

Encapsulation Class versus object

Case Study

After this module, you should be able to

Write a console application with more than 3classes


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Identifying Objects: Abstraction

Determine the relevant properties and features while

ignoring non-essential details

Cat

- bloodType- numberOfBones- lastVisitDate

abstraction

Cat

- birthday- favouriteFood- favouriteToy


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Classes

Aclass is the blueprint from which individual

objects are created. An object is an instance of a class.

Object factory

Cookie Cutter

public class StudentTest {

public static void main(String[] args) {Student s1 = new Student();Student s2 = new Student();

}} - class -

public class Student {private String name;

// }


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Case Study

Uncle Kevin needs a rental system for his DVD

rental shop. Standalone application

Used by the cashier

Features List all DVDs

Add a DVD

Rent a DVD

List all Rentals

Assumption

1 copy per title


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Step 1: Object-Model Components as a Guide

Start off with the following groups of objects

Problem domain Classes related to the business at hand

Data Management (Not covered in IS200)

Databases, files etc (to persist data over time)

Human interaction

Windows, reports etc

System interaction (Not covered in IS200)

Objects that provide an interface between problemdomain objects and other systems or devices


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Application

Step 1: Object-Model Components as a Guide

DataManagement

Problem domain

SystemInteraction

FilesDatabases

ExternalSystems

HumanInteraction

Start off with the following groups of objects


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Step 2: Identify Actors, places & things

Actors and participants

Actors are people and organizations that act as participantswithin the system under consideration

You need a way to know each object and its attributes

Example: Cashier, Clerk etc

Places Look for places where things come to rest, places that contain

other object

Example: Airport, Warehouse, School

Things

Tangible objects used in the problem domain

Example: CashBox, Product, Stock, Facility


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Step 3: Transactions

Recording or logging of any event of significance

Look for events that the system must remember over time Loan

Remember which book is borrowed by which Patron

Receipt

Remember which product(s) is bought by which Customer


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DVD Rental System: Identifying Objects

Actors and participants

Clerk ?

Places

Shop ?

Things Patron/Borrower

DVD

Transaction

Rental


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Exercise Write the DVD class

Implement the DVD class.

Has 2 attributes: id of type int

1,2,3,

Used to identify a DVD object

title of type String

Has a specific constructor:

DVD(int id, String title)

Implement the getter methods


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Exercise: Write the DVDManager - 1

DVDManager is responsible for managing the DVD

objects Has one attribute

dvdList of type ArrayList

Has a default constructor that creates the followingobjects

ID Title

1 Bride Wars

2 17 Again3 Knowing

4 Seventh Moon

5 Night Train


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Exercise: Write the DVDManager - 2

Has the following methods

ArrayList retrieveAll() Returns all the DVDs

DVD retrieve(int id)

Returns the DVD which has the specific id

Void add(String title)

Add a DVD object with the specific title


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14Obj t O i t d A li ti D l t

Summary

Abstraction

Determine the relevantproperties and featureswhile ignoring non-essential details

Aclass is the blueprintfrom which individualobjects are created.

An object is an instance ofa class.

Working on a Object-

Oriented project Start off with the following

groups of objects

Problem domain

Data Management

Human interaction

System interaction

Identify actors andparticipants, places &

things Identify transactions

09-Building-an-Application-V1 (1).ppt

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