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

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 (2 nd 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!

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

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”) Larman p. 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 Larman p. 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) Larman p. 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

Larman’s Text Approach 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)

Larman’s Text Approach 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 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?

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

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