Information Systems Analysis and Design Overview of OOAD, UML, and RUP

INFO 620 Lecture #1 1

Information Systems Analysis and Design

Overview of OOAD, UML, and RUP

INFO 620

Glenn Booker


Syllabus

• This course is about learning and applying Object-Oriented Analysis and Design (OOA&D), expressed using the Unified Modeling Language (UML)

• Primary text is Larman’s Applying UML and Patterns (2nd ed.)

• Quatrani’s Visual Modeling with Rational Rose 2002 and UML is for Rose users


Your Background

• How much experience do you have with:– Programming?– Object oriented programming?– If any, what programming languages are

you most comfortable using?

• Other than your grade, are there any aspects of this course in which you’re most interested?


More than Software

• The texts are focused only on software

• Remember that your system will probably involve other things, such as:– Hardware– Users– Training– Documentation, etc.


What is Object Oriented?

• Earlier analysis methods were focused on process (such as a Data Flow Diagram, or DFD) or data (e.g. using an Entity Relationship Diagram, or ERD)

• Object oriented (OO) methods blend data and process into objects, and focuses on how those objects interact using methods (passing messages)


What is Object Oriented?

• Traditional design creates entities (data tables), and changes them using scripts, procedures, macros, or other techniques

• OOA&D creates objects from classes, and applies them using their methods or operations

Image from Apple, “Object-Oriented Programming and the Objective-C Language”


What is an Object?

• “An entity with a well-defined boundary and identity that encapsulates state and behavior. State is represented by attributes and relationships, behavior is represented by operations, methods, and state machines. An object is an instance of a class.” (UML 1.5 spec – see slide 22)


Huh?

• Attributes are the data contained by an object, if any

• Relationships describe which objects are allowed to talk to each other

• The operations and methods describe the ways objects can interact with each other

• So objects are a set of data which can only be acted on in certain prescribed ways


What is a Class?

• “A description of a set of objects that share the same attributes, operations, methods, relationships, and semantics. A class may use a set of interfaces to specify collections of operations it provides to its environment.” (UML 1.5 spec)

• Hence a class is a group of similar objects


OO Languages

• Common object-oriented languages include the cousins C++, Java, and C# (C sharp)

• Lesser known OO languages include– Smalltalk (first OO language, 1980)– Ada 95 (highly reliable, real-time systems)– Objective-C (Macintosh)– And many, even more obscure languages


The Old Ways

• Process Oriented Methodology– Invented in the 1960’s– Focuses on using DFD– Weak for projects over 50k LOC– Subject to frequent change (every time a

process is tweaked, the DFD changes)


The Old Ways

• Data Oriented Methodology– Introduced in 1976, and primary method

used from the 1980’s to today– Focuses on using the ERD– Doesn’t change as often as the DFD– Shows business rules through cardinality

(0, 1, )– Works for systems up to about ½ million LOC


The New Way

• Object Oriented Methodology– Encapsulates data and processes to allow large

system development (millions of LOC)– Getting standardized (UML, CORBA)– Slow to be adopted by industry, mostly due

to inertia of data and process methods (large installed base)


OO Objectives

• We want a development method which:– Is able to guide us through analysis, design, and

implementation using one consistent paradigm throughout those phases

– Is less likely to generate errors– Contains checks to help eliminate errors– Facilitates reuse of designs and code


Object Oriented Analysis

• OOA is “a method of analysis that examines requirements from the perspectives of the classes and objects.” (Booch 1995)

• Emphasis is on finding and describing conceptual objects which are relevant to your problem


Object Oriented Design

• OOD is “a method of design encompassing the process of OO decomposition and a notation for depicting both logical and physical as well as static and dynamic models of the system.” (Booch 1995)

• Emphasis is on defining software objects, and how they collaborate to fulfill system requirements


Analysis and Design

• Like the process and data methodologies, note that:– OO Analysis is done with no concern of how it

will be implemented– OO Design considers implementation issues

• Also note that there are conceptual objects (analysis) and software objects (design)


Analysis vs. Modeling

• Analysis is the process of understanding something

• The results of analysis may be captured (expressed) using modeling

• Modeling depends on have some language to express the concepts

• UML is a language for modeling OOA&D


Why use UML?

• UML replaced a herd of competing OO methods from the early to mid 1990’s, e.g.:– OMT method (most popular, Rumbaugh)– Mainstream Objects(MO) method, Ed Yourdon– Objectory method (Jacobson)– Booch method (Booch *duh*)– CRC method (Wirfs-Brock)– Fusion method (developed by Coleman (HP))


Why use UML?

• Around 1995, five OO methods shared 75% of the market– OMT led with 34-40% of market, hence UML

was based on the OMT method– Booch and Schlaer Mellor were also popular

• All other methods shared remaining 25% of the market, including corporate-defined OO methods


Unified Modeling Language

• The “three amigos” created UML in 1997-8– Grady Booch– James Rumbaugh– Ivar Jacobson

• Their three 1999 books are instant classics:– The UML: User Guide– The UML: Reference Manual– The Unified Software Development Process

(ISBNs 0201571684, 020130998X, and 0201571692)


Intro to UML

• UML is defined by the Object Management Group (www.omg.org), a worldwide consortium of OO product vendors

• First standardized in 1997

• Latest version is 1.5 (March 2003)*

• Booch, Rumbaugh, and Jacobson all work for Rational Software Inc. (rational.com)

*A rather dry 736-page tome…but nice glossary!

http://www.omg.org/technology/documents/formal/uml.htm


UML Goals

• The goals of UML are:– To model systems using OO concepts– To establish an explicit coupling between

conceptual and software artifacts (objects)– To address the issues of scale inherent in

complex mission critical systems– To create a modeling language usable by both

humans and machines


UML Lineage

• UML not only replaced the methods by Booch, Rumbaugh, and Jacobson, but also borrowed from:– Fusion (Operation description &

message numbering) – Embley (Singleton class)– Meyer (Pre- and post-conditions)– Shlaer and Mellor (Object life cycles)


UML Lineage

– Martin and Odell (Classification)– Wirfs-Brock (Responsibilities)– Harel (State charts)– Gamma, et al (Patterns)

• So UML borrowed from all of the best ideas


UML and OOA&D

• UML has twelve diagrams, but three types are most commonly used– “Use case” modeling– Class modeling– Interaction modeling with patterns

• Just because English has 600,000 words doesn’t mean you need to use them all – 3000 is plenty for most occasions


UML Method

• A method needs a language, and a process to describe how to use the language Method = Language + Process

• The Rational Unified Process (RUP or UP) was designed to be used with UML– UP is an iterative process– Provides a structure for system development


More RUP Info

• Rational has lots of white papers if you’re interested in the Rational Unified Process (good even if you’re not using Rose), Rose, or the Suite DevelopmentStudio (sic)

• Or you can buy additional documentation on their products (extremely optional!)– See Rose download instructions for more

documentation info

https://www.rational.com/products/whitepapers/index.jsp

https://www.rational.com/support/documentation/index.jsp


Iterative Development

• System is defined by use cases– A “use case” is a major way of using the

system, or a major type of functionality

• High level planning needs to – Define what are the major use cases– Determine in what order they will be done– Estimate development time for each use

case (“timeboxing”)

Larmanp. 15


Iterative Development

• Each development iteration creates one use case– Includes the entire life cycle (requirements

analysis, design, implementation, and testing)– Results in an executable portion of the system

or some other clearly defined end product• E.g. an ATM which can only do withdrawals

– Is planned with a fixed time to completion


UP Phases

• Inception

• Elaboration

• Construction

• Transition

Larmanp. 19


Inception Phase

• Conduct feasibility study

• Define approximate vision, business cases, and scope for project

• Develop vague estimates (size, cost, and schedule)


Elaboration Phase

• Refine vision

• Identify most requirements and scope

• Do iterative implementation of the system’s core architecture

• Resolve high risks


Construction Phase

• Do iterative implementation of the system’s easier and lower risk elements

• Prepare for deployment


Transition Phase

• Conduct beta tests

• Deploy system


UP Disciplines

• A discipline is a set of activities and the related artifacts created by those activities

• An artifact is any work product – code, documents, diagrams, models, etc.

• This course focused on three disciplines:– Business Modeling– Requirements Analysis– Design


Other UP Disciplines

• Other UP Disciplines include– Implementation (programming & building

the system)– Test– Deployment (releasing the system)– Configuration and Change Management– Project Management– Environment (create development environment)

Larmanp. 21


Iteration, Disciplines, Phases

• Each iteration may use some or all of the disciplines, depending on when that iteration occurs in development

• Likewise, the Phases may each correspond to one or more iterations (p. 22 Larman), so each Phase will also use some or all of the disciplines


Larman’s Text Approach

• Larman uses three iterations– Inception– Iteration 1– Iteration 2– Iteration 3

• Course only uses one big iteration, due to time constraints



• Inception– Basic requirements analysis– Use case modeling

• Iteration 1– Fundamental OOAD– Assign responsibilities (define who does what)– Build domain models (class models and

interaction diagrams)



• Iteration 2– Object design with design patterns– GRASP patterns (a Larman term)

• Iteration 3– Architectural analysis and framework design– Relating use cases– Refine domain models with generalization and

advanced modeling


OO Concepts – Class

• A Class is a group of objects with common features and common behaviors such as– Attributes– Operations– Relationships with other objects

• A Class has two components– Data (SSN, height, price, ISBN, etc.)– Operations (interfaces or methods)


OO Concepts - Object

• An Object is any meaningful concept, abstraction, or thing for the problem at hand

• An Object is an instance of a class– Bill Clinton is an object, of the class Customer

• Objects have three components– Data– Operations (interfaces or methods)– Object identity (OID); like entity’s primary key


OO Concepts – Operations

• Interface– A logical description of the way objects interact– Describes the functions (play, record, hire)

• Method– A physical implementation of how objects

interact; or of an operation for a class– “Pushing the VCR button” is a method


OO Paradigm

• All OO things (A&D methods, databases, interfaces, operating systems, etc.) have four common characteristics:– Abstraction– Encapsulation– Generalization & Specialization, Inheritance– Polymorphism


Abstraction

• Abstraction is the process of modeling only relevant features– Hide unnecessary details which are irrelevant

for current purpose (and/or user), like eye color

• Reduces complexity and aids understanding

• Done via class, inheritance, association, and aggregation concepts


Encapsulation

• Encapsulation is the integration of data and operations into a class

• Supports information hiding by concealing implementation of the object

• Allows us to call a function without knowing, or caring, how it’s implemented– Sqrt(x)


Encapsulation

We don’t access data directly – ever!

Only access data via messages between objects


Generalization & Specialization

• Generalization is the process of identifying common features among classes leading to superclasses

• Specialization is the process of creating more specialized subclasses from an existing class


Inheritance

• Subclasses inherit all of the properties and operations defined for the superclass, and will usually add more

• Sometimes modeled using “is a” or “AKO” (a kind of) concepts


Inheritance

Wheeled

Vehicle

Two wheeled

Not Wheeled

Four wheeled Tank

Generalization

Specialization

Class

Superclass

Subclass


Inheritance

• Is an implementation concept• Substitutability means the subclass must

be usable when its superclass object is expected

• Subtyping is using inheritance based on substitutability

• Example could also be broken by powered vs. unpowered, or land vs. air, or other ways


Inheritance

• Could also look to biology for examples• A “human being” inherits properties and

characteristics from– Primates, and– Mammals, and– Animals

• But it doesn’t perform the function photosynthesis, because it isn’t a Plant


Polymorphism

• Means “many shapes”• Allows dynamic substitution of objects

within an inheritance hierarchy• Allows services to be shared by many

classes (a.k.a. overloading a function)– A method called “calculate area” for a class

“drawing object” will have different definitions depending on whether the drawing object is a triangle, square, diamond, circle, etc.


Architectural Concepts

• Software is often written to different levels of the system’s architecture – – User Interface (what the user sees)– Application (the body of your software)– Technical Services (general purpose services to

support your application)

• These later correspond to different computer systems which implement them


Inception Phase

• The inception phase focuses on analyzing the feasibility of a project– Can we make a business case to prove this

project is a good idea?– Is this project technically feasible?– Very roughly, how much time and money will

this project need?– What risks can we foresee?

Documents

Information Systems Analysis and Design Overview of OOAD, UML, and RUP