Systems Analysis and Design in a
Changing World, Fourth Edition
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Overview
 The
IS discipline is dynamic and always changing
 More
complex system requirements have
necessitated a whole new set of tools

The Unified Process (UP)

Radical, adaptive approaches, including Agile
Development, Extreme Programming, and Scrum

Model-Driven Architecture for enterprise-level
systems

Object frameworks and components to increase
productivity and quality
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Software Principles and Practices



The effort to develop current solutions is demanding
Current trends in modeling and development processes use five important
principles:
Abstraction


Models and modeling


Standard solutions to a given problem or templates that can be applied to a
problem
Reuse


An abstraction of something in the real world, representing a particular set of
properties
Patterns


Process of extracting core principles from a set of facts or statement
Building standard solutions and components that can be used over and over again
Methodologies

A process—including the rules, guidelines, and techniques—that defines how
systems are built
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Adaptive Approaches to Development
 Opposite
end of spectrum from predictive
approaches
 Allow
 Use
for uncertainty
empirical controls, not predictive controls

Describe processes that are variable and
unpredictable

Monitor progress and make corrections on the fly
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Adaptive Approaches to Development—
Characteristics
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 Less
emphasis on up-front analysis, design, and
documentation
 More
focus on incremental development
 More
user involvement in project teams
 Reduced

detailed planning
Used for near-term work phases only
 Tightly
control schedules by fitting work into
discrete time boxes
 More
use of small work teams that are selforganizing
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The Unified Process (UP)
 Object-oriented
system development
methodology (system development process)
 Offered
by Rational/IBM, UP developed by
Booch, Rumbaugh, and Jacobson
 UP
should be tailored to organizational and
project needs
 Highly
iterative life cycle
 Project
will be use-case driven and modeled
using UML
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The Unified Process Life Cycle
 UP
life cycle

Includes four phases which consist of iterations

Iterations are “mini-projects”
 Inception
– develop and refine system vision
– define requirements and design
and implement core architecture
 Elaboration
– continue design and
implementation of routine, less risky parts
 Construction
 Transition
– move the system into operational
mode
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The Unified Process Life Cycle (Figure 16-1)
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UP Phases and Objectives (Figure 16-2)
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The UP Disciplines
 Discipline
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– set of functionally related development
activities
 Each
iteration includes activities from all disciplines
in each discipline produce artifacts –
models, documents, source code, and executables
 Activities
 Six

main UP development disciplines
Business modeling, requirements, design, implementation,
testing, and deployment
 Three

additional support disciplines
Project management, configuration and change management,
and environment
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UP Disciplines Used in Varying Amounts in 16
Each Iteration (Figure 16-3)
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UP Life Cycle Model
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Showing Phases, Iterations, and Disciplines (Figure 16-4)
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The Agile Development Philosophy and
Modeling
 Agile

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Development
A philosophy and set of guidelines for developing
software in an unknown, rapidly changing
environment
agility – being able to change direction
rapidly, even in the middle of a project
 Requires
 Agile

Modeling
A philosophy about how to build models, some of
which are formal and detailed and others are
sketchy and minimal
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The Agile Development Philosophy and
Values
 Responding

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to change over following a plan
An agile project is chaordic – both chaotic and
ordered
 Individuals
and interactions over processes and
tools
 Working
software over comprehensive
documentation
 Customer
collaboration over contract negotiation
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Adaptive Methodologies Using Agile
Modeling (Figure 16-5)
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Agile Modeling Principles
 AM
is about doing the right kind of modeling at
the right level of detail for the right purposes

Use models as a means to an end instead of
building models as end deliverables

Does not dictate which models to build or how
formal to make those models

Has basic principles to express the attitude that
developers should have as they develop software
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Agile Modeling Principles (Figure 16-6)
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Agile
Modeling
Practices
(Figure 16-7)
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Extreme Programming (XP)
 An
adaptive, agile development methodology
created in the mid-1990s
 Takes
proven industry best practices and focuses
on them intensely
 Combines
those best practices (in their intense
form) in a new way to produce a result that is
greater than the sum of the parts
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XP Core Values
 Communication

In open, frequent verbal discussions
 Simplicity

In designing and implementing solutions
 Feedback

On functionality, requirements, designs, and code
 Courage

In facing choices such as throwing away bad code
or standing up to a too-tight schedule
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Some XP Practices
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
Planning - Users develop a set of stories to describe what the system needs
to do
Testing - Tests are written before solutions are implemented
Pair programming - Two programmers work together on designing, coding,
and testing
Simple designs - “KISS” and design continuously

Refactoring - Improving code without changing what it does

Owning the code collectively - Anyone can modify any piece of code

Continuous integration - Small pieces of code are integrated into the system
daily or more often

System metaphor - Guides members towards a vision of the system

On-site customer - Intensive user/customer interaction required

Small releases - Produce small and frequent releases to user/customer

Forty-hour work week - Project should be managed to avoid burnout

Coding standards - Follow coding standards to ensure flexibility



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XP
Development
Approach
(Figure 16-9)
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Scrum

A quick, adaptive, and self-organizing development methodology

Responds to a current situation as rapidly and positively as possible

A truly empirical process control approach to developing software

Responsive to a highly changing, dynamic environment

Focuses primarily on the team level


Team exerts total control over its own organization and work
processes
Uses a product backlog as the basic control mechanism

Prioritized list of user requirements used to choose work to be done
during a Scrum project
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Scrum Organization
 Product
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owner

The client stakeholder for whom a system is being
built

Maintains the product backlog list
 Scrum

master
Person in charge of a Scrum project
 Scrum
team or teams

Small group of developers

Set their own goals and distribute work among
themselves
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Scrum Practices
 Sprint

The basic work process in Scrum

A time-controlled mini-project

Firm 30-day time box with a specific goal or
deliverable
 Parts
of a sprint

Begins with a one-day planning session

A short daily Scrum meeting to report progress

Ends with a final half-day review
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Project Management and Methodologies
 Project time management
 Smaller scope and focused on
each iteration
 Realistic work schedules
 Project scope management
 Users and clients are responsible
for the scope
 Scope control consists of
controlling the number of iterations
 Project cost management
 More difficult to predict because of
unknowns
 Project communication management
 Critical because of open verbal
communication and collaborative
work
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 Project quality management
 Continual testing and refactoring
must be scheduled
 Project risk management
 High-risk aspects addresses in
early iterations
 Project human resource management
 Teams organize themselves
 Project procurement management
 Integrating purchased elements
into the overall project
 Verifying quality or components
 Satisfying contractual
commitments
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Model-Driven Architecture—Generalizing Solutions



Model-Driven Architecture (MDA) is an OMG (Object Management
Group) initiative

Built on the principles of abstraction, modeling, reuse, and patterns

Provides companies with a framework to identify and classify all
system development work being done in an enterprise
Platform-independent model (PIM)

Describes system characteristics that are not specific to any
deployment diagram

Uses UML
Platform-specific model (PSM)


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Describes system characteristics that include deployment platform
requirements
A set of standard transformations by the OMG move a PSM to a PIM
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Software
Development
and MDA
(Figure 16-11)
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Object Frameworks
 A set
of classes that are designed to be reused in
a variety of programs
 The
classes within an object framework are
called foundation classes

Can be organized into one or more inheritance
hierarchies

Application-specific classes can be derived from
existing foundation classes
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Object Framework Types
 User-interface

Commonly used objects within a GUI
 Generic

data structure classes
Linked lists, binary trees, and so on, and related processing
operations
 Relational

database interface classes
Classes to create and perform operations on tables
 Classes

classes
specific to an application area
For use in a specific industry or application type
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Impact on Design and Implementation
 Frameworks
must be chosen early in the project
 Systems
design must conform to specific
assumptions about application program structure
and operation that the framework imposes
 Design
and development personnel must be
trained to use a framework effectively
 Multiple
frameworks might be required,
necessitating early compatibility and integration
testing
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Components

Software modules that are fully assembled and ready to
use


Have well-defined interfaces to connect them to clients or
other components


Reusable packages of executable code
Public interfaces and encapsulated implementation
Standardized and interchangeable

Updating a single component does not require relinking,
recompiling, and redistributing an entire application
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Component Standards and Infrastructure
 Interoperability
of components requires standards
to be developed and readily available
 Components
might also require standard support
infrastructure

Software components have more flexibility when
they can rely on standard infrastructure services to
find other components
 Networking
standards are required for
components in different locations
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CORBA and COM+
 CORBA
(Common Object Request Broker
Architecture) is a standard for software
component connection and interaction developed
by the OMG

An object request broker (ORB) provides
component directory and communication services

The Internet Inter-ORB Protocol (IIOP) is used to
communicate among objects and ORBs
 Component
Object Model Plus (COM+) is a
standard for software component connection and
interaction developed by Microsoft
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Enterprise JavaBeans
 Part
of the Java programming language’s
extensive object framework (JDK)
 A JavaBean
can execute on a server and
communicate with clients and other components
using CORBA

A JavaBean implements the required component
methods and follows the required naming
conventions of the JavaBean standard
 Platform
independent
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Components and the Development Life Cycle
 Component
purchase and reuse is a viable
approach to speeding completion of a system

Purchased components can form all or part of a
newly developed or re-implemented system

Components can be designed in-house and
deployed in a newly developed or re-implemented
system
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Using Purchased Components—
Implications
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 Standards
and support software of purchased
components must become part of the technical
requirements definition
 A component’s
technical support requirements
restrict the options considered during software
architectural design
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Services
 New
method of software reuse enabled by
Internet—external services identified and used for
applications
 Called
Web services and service-oriented
architecture (SOA)
 Microsoft
.NET is service standard based on
SOAP
 Java
2 Web Services (J2WS) is service standard
for services in Java
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