1. CSCI 360: Software Architecture & Design
Dr. X

2. Outline Recap previous class Iterative Development Case Studies
Github!

3. Architecture and Design
Architecture: the complex or carefully designed structure of something. (dictionary.com)
Design: purpose, planning, or intention that exists or is thought to exist behind an action, fact, or material object. (dictionary.com)

4. OOAD OOA: find and describe objects in the problem domain.
OOD: define objects and how they collaborate to fulfil requirements.
OOAD Steps:
Define Use Cases
Define Domain Model
Define Interaction Diagrams
Define Design Class Diagrams
Use case: stories, scenarios of how product will be used
Domain model: noteworthy concepts or objects
Interaction: sequence

5. UML as a sketch

6. UML as a sketch
Is visual modeling a good thing and why?

7. From Design to Implementation
Analysis
investigation
of the problem
Design
logical solution
Construction
code
public class Book {
public void print();
private String title; }
Book
Book
(concept)
title
print()
Domain concept
Representation in
analysis of concepts
Representation in an
object-oriented
programming language.

8. The Unified Process (UP)
A process is a set of partially ordered steps intended to reach a goal.
What is the goal in Software Engineering?
Based on the above definition, what is the software process?
The Unified Process (UP) is a process for building object-oriented systems.
What is the goal of UP?
Software Engineering Goals: Software engineering is the application of engineering to the development of software in a systematic method
Readability
Correctness
Reliability
Reusability
Extensibility
Flexibility
Efficiency
What is a SW process? In software engineering, a software development process is the process of dividing software development work into distinct phases to improve design, product management, and project management. It is also known as a software development life cycle.
What is the goal of UP? The goal of the UP is to enable the production of high quality software that meets users needs within predictable schedules and budgets.

9. Iterative Development
[iteration N]
Requirements – Analysis - Design- Implementation - Testing
[iteration N+1]
Requirements – Analysis - Design- Implementation - Testing
Feedback from iteration N leads to
refinement and adaptation of the
requirements and design in iteration
N+1.
The system grows
incrementally.

10. Iterative Development
How do we organize development?
What does an iteration represent?
What is the input of an iteration?
What is the output of an iteration?
Why should we as developers embrace iterative development and change?
Is the output of an iteration a throwaway prototype or a production grade subset of a system?
If you find yourself in an iterative project where you try to define all the requirements and UML models before programming, then you have fallen in the trap of waterfall thinking!
Change is the constant in Sw projects
Feedback, adaptation to marketplace and change! Agility: rapid and flexible response to change!
The output of an iteration is not an experimental prototype but a production subset of the final system.
Each iteration tackles new requirements and incrementally extends the system.
An iteration may occasionally revisit existing software and improve it
Stakeholders usually have changing requirements.
Each iteration involves choosing a small subset of the requirements and quickly design, implement and testing them.
This leads to rapid feedback, and an opportunity to modify or adapt understanding of the requirements or design.

11. Iteration Length and Timeboxing
What is the recommendation of UP for iteration length and why?
What is timeboxing? How does it manage change or lack of enough time?
The UP recommends short iteration lengths to allow for rapid feedback and adaptation.
Long iterations increase project risk.
Iterations are fixed in length (timeboxed).If meeting deadline seems to be difficult, then remove tasks or requirements from the iteration and include them in a future iteration.
The UP recommends that an iteration should be between two and six weeks in duration.

12. Phases of the Unified Process
Inception
Elaboration
Construction
Transition
time
A UP project organizes the work and iterations across four major phases:
Inception - Define the scope of project.
Elaboration - Plan project, specify features, baseline architecture.
Construction - Build the product
Transition - Transition the product into end user community
Inception – vision
Elaboration – model
Construction – coding
Transition - testing

13. Iterations and Milestones
Inception
Elaboration
Construction
Transition
What is the focus of a release or iteration?
What does a milestone review provide?
What marks the end of an iteration?
Preliminary
Iteration
Iter. #1
Iter. #2
Milestone
Release
Final production
release
Always remember that a phase can have several iterations in it. An iteration does not contain any phases!
Each phase and iteration has some risk mitigation focus, and concludes with a well-defined milestone.
The milestone review provides a point in time to assess how well key goals have been met and whether the project needs to be restructured in any way to proceed.
The end of each iteration is a minor release, a stable executable subset of the final product.

14. Preliminary Iteration(s)
The UP Disciplines
Phases
Inception
Elaboration
Construction
Transition
Process Disciplines
Business Modeling
Requirements
Analysis & Design
Implementation
Test
Deployment
Each iteration has a mix of disciplines (requirements, domain, design, code) and so a phase will have several repetitions of a little life cycle. However the mix of disciplines tends to be different in each phase.
The disciplines are like tools that are used in many phases. However in the early phases we normally do more business modeling and requirements than Design and Implementation. In later phases this is reversed.
Supporting Disciplines
Configuration Mgmt
Management
Environment
Preliminary Iteration(s)
Iter. #1
Iter. #2
Iter. #n
Iter. #n+1
Iter. #n+2
Iter. #m
Iter. #m+1
Iterations

15. Preliminary Iteration(s)
The UP Disciplines
In an iteration you
walk through all
disciplines.
Phases
Process Disciplines
Inception
Elaboration
Construction
Transition
Business Modeling
Requirements
Analysis & Design
Implementation
Test
Deployment
Supporting Disciplines
Configuration Mgmt
Management
Environment
Preliminary Iteration(s)
Iter. #1
Iter. #2
Iter. #n
Iter. #n+1
Iter. #n+2
Iter. #m
Iter. #m+1
Iterations

16. Preliminary Iteration(s)
The UP Disciplines
Focus of this
course.
Phases
Process Disciplines
Inception
Elaboration
Construction
Transition
Business Modeling
Requirements
Analysis & Design
Implementation
Test
Deployment
Supporting Disciplines
Although an iteration includes work in most disciplines, the relative effort and emphasis change over time.
Early iterations tend to apply greater emphasis to requirements and design, and later ones less so.
Figure illustrations are suggestive, not literal.
Note that activities and artifacts are optional (except code!)
Developers select those artifacts that address their particular needs.
Configuration Mgmt
Management
Environment
Preliminary Iteration(s)
Iter. #1
Iter. #2
Iter. #n
Iter. #n+1
Iter. #n+2
Iter. #m
Iter. #m+1
Iterations

17. Advantages of an Iterative Process
Reduce risks
Risks are identified early, progress is easier to see.
Get a robust architecture
Architecture can be assessed and improve early.
Handle evolving requirements
Users provide feedback to operational systems.
Responding to feedback is an incremental change.
Allow for changes
System can adapt to problems
Attain early learning
Everyone obtains an understanding of the different workflows early on.

18. Agile cake
Would you plan to eat it one layer at a time: (1) all the Requirements, (2)all the Design, (3) Code it all and then (4) do the tests

19. Agile Manifesto
Individuals and interactions over processes and tools Working software over comprehensive documentation Customer collaboration over contract negotiation Responding to change over following a plan

20. Fig. 3.1

21. Case Study: NextGen POS System

22. Fig. 3.2