objectives

2Object-Oriented Analysis and Design with the Unified Process

Objectives Explain the purpose and various phases of the

traditional systems development life cycle (SDLC) Explain when to use an adaptive approach to the

SDLC in place of the more predictive traditional SDLC

Describe how the more adaptive Unified Process (UP) life cycle uses iterative and incremental development

Explain the differences between a model, a tool, a technique, and a methodology


Objectives (continued)

Describe the Unified Process as a comprehensive system development methodology that combines proven best practices with the iterative UP life cycle

Describe the disciplines used in a UP development project

Describe the key features of the object-oriented approach

Explain how automated tools are used in system development


Overview

Traditional systems development life cycle (SDLC) Unified Process (UP)

Iterative, incremental, adaptive approach to life cycle Nine disciplines: six for system development, three

for support Review object-oriented (OO) concepts Describe computer support tools such as CASE Apply UP to the development project of RMO


The Systems Development Life

Cycle SDLC: process of building, deploying, using, and

updating an information system Chief variations of SDLC

Predictive: project planned entirely in advance Adaptive: planning leaves room for contingencies

Pure approaches to SDLC are rare Most projects have predictive and adaptive elements


Figure 2-1Predictive versus adaptive approaches to the SDLC


The Systems Development Life Cycle

Predictive approach Example: A company that want to convert its old,

mainframe inventory system to a newer networked client/server system.


The Traditional Predictive SDLC Approaches

Five activities or phases in a project Planning, analysis, design, implementation, support

Pure waterfall approach (predictive SDLC) Assumes project phases can be sequentially executed Project drops over the “waterfall” into the next phase

Modified waterfall approach The phases of project must overlap, influencing and

depending on each other.


Figure 2-3SDLC Phases and Objectives


Figure 2-4The Waterfall Approach to the SDLC


PROJECT PLANNINGPROJECT PLANNING ADDITIONAL PROJECT MANAGEMENT TASKSADDITIONAL PROJECT MANAGEMENT TASKS

ANALYSISANALYSIS ADDITIONAL ANALYSIS ACTIVITIES

ADDITIONAL ANALYSIS ACTIVITIES

DESIGNDESIGN ADDITIONAL DESIGN ACTIVITIES

ADDITIONAL DESIGN ACTIVITIES

IMPLEMENTATIONIMPLEMENTATION

SUPPORT

Figure 2-5The Overlap of System Development

Activities


The Newer Adaptive Approaches to the SDLC

The spiral model: early form of adaptive SDLC Activities radiate from center starting point Prototypes are artifacts of each phase

Iterative problem solving: repeats activities Several approaches to structuring iterations

Define and implement the key system functions Focus on one subsystem at a time Define by complexity or risk of certain components Complete parts incrementally


Figure 2-6The Spiral Life Cycle Model


The Unified Process Life Cycle

UP life cycle

Includes (4) phases which consist of iterations

Iterations are “mini-projects”

Inception: develop and refine system vision

Elaboration: define requirements and core architecture

Construction: continue design and implementation

Transition: move the system into operational mode


Figure 2-8The Unified Process System Development Life Cycle


Figure 2-9UP Phases and Objectives


Methodologies, Models, Tools, and Techniques

Analysts have a wide variety of aids to help them complete activities and tasks in system development beyond SDLC.


Methodologies and System Development Processes

System development methodology

Provides guidelines every activity in system development

Includes specific models, tools, and techniques

UP is a system development methodology

Methodologies supported with documentation


Models A model is a representation of an important aspect of the real

world.

Models come in many forms

Physical analogs, mathematical, graphical

System development models are highly abstract

Depict inputs, outputs, processes, data, objects, interactions, locations, networks, and devices

Unified Modeling Language (UML): standard notation

PERT or Gantt charts: model project itself


Figure 2-10Some Models used in System Development


Tools

Tool: software used to create models or components

Example tools

Project management software tools (Microsoft Project)

Integrated development environments (IDEs)

Code generators

Computer-aided system engineering (CASE)


Tools Integrated development environments (IDEs) is a software application

that provides comprehensive facilities to computer programmers for software development.

An IDE normally consists of a:

– source code editor,

– compiler and/or interpreter,

– build automation tools, and

– debugger (usually).

Example: Eclipse, Mic. Visual Studio and recent versions of Netbeans


Techniques Technique

Collection of guidelines

Enables an analyst to complete an activity or task

Example techniques

Domain-modeling , use case modeling, software-testing, user-interviewing techniques, relational database design techniques

Proven techniques are embraced as “Best Practices”


Figure 2-13Relationships of Models, Tools, and Techniques in a System

Development Methodology


The Unified Process as a System Development Methodology

UP: object-oriented system development methodology , offered by Rational Software, which is now part of IBM.

UP should be tailored to organizational and project needs

Project will be use case driven


The Unified Process as a System Development Methodology

(continued) Use case

Activity that the system carries out Basis for defining requirements and designs

UP defines disciplines within each phase Discipline: set of functionally related activities Iterations concatenate activities from all disciplines Activities in each discipline produce artifacts; models,

documents, source code, and executables


Figure 2-15UP Life Cycle with Phases, Iterations, and Disciplines


The UP Disciplines Six main UP development disciplines

Business modeling, requirements, design, implementation, testing, and deployment

Each iteration Similar to a mini-project Results in a completed portion of the system

Three additional support disciplines Project management, configuration and change

management, and environment


Business Modeling

Purpose: understand business environment

Three major activities part of business modeling

Understand surroundings

Create the system vision (define - system objective, system capabilities and primary business benefits)

Create business models


Requirements

Objective: document business requirements Key drivers of activities: discovery and

understanding Activities list

Gather detailed information Define functional and nonfunctional requirements Develop user interface dialogs Evaluate requirements with users


Design Objective: design system based on requirements Six major activities in the design discipline

Design support services architecture and deployment environment

Design the software architecture Design use case realizations (the design of the s/ware that

implements each use case)

Design the database Design the system and user interfaces Design the system security and controls


Implementation

Objective: build or acquire needed system components

Implementation activities

Build software components

Acquire software components

Integrate software components


Testing Testing is critical discipline

Testing activities

Define and conduct unit testing

Define and conduct integration testing

Define and conduct usability testing

Define and conduct user acceptance testing

In UP, acceptance testing occurs throughout the building phase


Deployment

Goal: conduct activities to make system operational

Deployment activities

Acquire hardware and system software

Package and install components

Train users

Convert and initialize data

Deployment activities prominent in transition phase


Project Management Most important support discipline

Project management activities

Finalize the system and project scope

Develop the project and iteration schedule

Identify project risks and confirm feasibility

Monitor and control the project’s plan

Monitor and control communications

Monitor and control risks and outstanding issues


Configuration and Change Management

As the project progresses, many changes occur in: Requirements

Design

Source code

Executables

The two activities in this discipline Develop change control procedures

Manage models and software components


Environment Managing development environment includes

Available facilities

Design of the workspace

Forums for team communication and interaction

Environment discipline activities Select and configure the development tools

Tailor the UP development process

Provide technical support services


Overview of Object-Oriented Concepts

OOA views system as a collection of objects

Object: entity capable of responding to messages

Languages: Simula, C++, Java, C#, Visual Basic .NET

Object-oriented design (OOD) Defines additional types of communication objects

Shows how the objects interact to complete tasks

Refines definition of objects for implementation

Object-oriented programming (OOP): object coding


Recognizing the Benefits of OO

Development Rationale for use in information systems

Benefits of naturalness

Reusability


Objects are More Natural OO approach mirrors human perception OOA, OOD, and OOP imitate perceptual processes by

modeling classes of objects Some system developers resist OO development They have get used to procedural programming Many experienced developers have had difficulty

learning the OO approach New programmers are more receptive to OO approach


Classes of Objects Can Be Reused

Classes of objects have a long shelf life

Example: Customer class adaptability

Reused in systems where customer objects needed

Extended through inheritance to a new subclass

Reused during analysis, design, or programming

Classes may be stored, with implementation hidden, in class libraries


Understanding Object-Oriented Concepts

Object: thing with attributes and behaviors

Types of objects

User interface

Problem domain objects

Attributes are associated with data

Behaviors are associated with methods, functions, and procedures


Figure 2-18Attributes and Methods in Problem Domain Objects


Understanding Object-Oriented Concepts (continued)

Class: defines what all objects of class represent

Objects are instances of a class

Customer object is an instance of a customer class

Objects interact through messages

Objects retain memory of transactions

Example:


UML diagram CheckingAccount class

Corresponding code for simple checking account object

Reference: The Object-Oriented Thought Process, 2nd Edition by Matt Weisfeld

attribute

method


Figure 2-20Order-processing system where objects interact by sending messages


Understanding Object-Oriented Concepts (continued)

Objects maintain association relationships Encapsulation: combining attributes and methods

into one unit Information hiding: separating specification from

implementation Inheritance: extending the characteristics of a class Polymorphism: ability for dissimilar objects to

respond to the same message

Encapsulation



Definition: Attributes (data) and behaviors (code) are encapsulated in to a single object.

attribute

methodsetter

getter

Encapsulation

In many cases, an attribute of the object will have both a getter and a setter – not always the case

What is always the case is that the getters and setters are used to control access to the attributes and this is a key part of encapsulation.



Encapsulation Class shown in previous slide cannot be executed

directly. Example of an application that uses CheckingAccount class to instantiate and use a CheckingAccount object.



object

Encapsulation

The application shown in previous slide instantiate a CheckingAccount object, called myAccount, set the value of balance to 40.00 and then print that balance out.

Output:

Starting myEncapsulation…..

Balance= 40.00



Information/ Data Hiding

Definition: Access to all of an object’s attributes is tightly controlled.

Accomplished by making all the attributes private.



Attribute is set to private

Information/ Data Hiding Trying to access the balance attribute directly

from the myAccount object.



myAccount.setBalance (40.00)

Information/ Data Hiding



Information/ Data Hiding If balance is declared to public, it will work but

violates the concept of data hiding. Data hiding, as with many other object-oriented

concepts, is a design decision. If the system is designed with attributes as private,

the compiler can help with enforcing data hiding. If the classes are designed with public attributes,

the application is not designed in an object-oriented manner.



Inheritance Inheritance allows a class to inherit the attributes

and methods of another class.



InheritanceThe Dog and Cat classes both inherit from Mammal. This means that a

Dog class actually has the following attributes:

eyeColor // inherited from Mammal

barkFrequency // defined only for Dogs

In the same vein, the Dog object has the following methods:

getEyeColor // inherited from Mammal

bark // defined only for Dogs



superclass

subclasses

Polymorphism Ability for dissimilar objects to respond to the

same message. Read below article:

http://www.developer.com/tech/article.php/10923_3332401_2






Tools to Support System Development

CASE (Computer Aided System Engineering) Database repository for information system

Set of tools that help analysts complete activities

Sample artifacts: models, automatically generated code

Variations on CASE Visual modeling tools

Integrated application development tools

Round-trip engineering tools


Figure 2-24A Case Tool Repository Contains All Information About the System


Tools to Support System Development (continued)

Microsoft Visio: emphasizes technical drawing Rational Rose

CASE tool supporting object-oriented approach Strongly identified with UP methodology

Together Pioneers round-trip engineering

◘ synchronizes graphical models with generated program code

Leverages UML diagrams


Figure 2-26Visual Modeling Tool Rational Rose Displaying UML Diagrams


Tools to Support System Development (continued)

Embarcadero Describe

Visual Modeling

Round-trip engineering

Rational XDE Professional

Integrates Microsoft Visual Studio.NET IDE

Also provides visual modeling and round-trip


Figure 2-29Rational XDE Professional is integrated with Visual Studio .NET


Summary

SDLC: set of activities required to complete system development project

Predictive SDLC: executes project in sequential phases (waterfall approach)

Adaptive SDLC: accommodates change and phase overlap

Spiral SDLC model introduces iterations (cycles)

UP is an adaptive system development methodology


Summary (continued) UP life cycle includes four phases-inception,

elaboration, construction, and transition

UP phases decomposed into one ore more iterations

Iterations involve work in nine UP disciplines

UP is object-oriented

Object-oriented concepts: object, class, methods, encapsulation, associations, inheritance, polymorphism

CASE: automation tools simplify development tasks

objectives

Documents

adaptive unified process

unified processfigure

sdlcobjectoriented analysis

process of building

sdlc phases

adaptive approaches

development projectdescribe

life cycledescribe