1. Software Architecture in Practice
RiSE’s Seminars
Bass’s book :: Chapters 1, 2
Eduardo Santana de Almeida

2. Summary The Architecture Business Cycle (Chapter 1)
Software architecture
Architecture Business Cycle (ABC)
Architectural activities
Architectural principles
What is software architecture? (Chapter 2)
Software architecture issues
Points of view
Well defined architecture
Structures and views

3. Software Architecture - context
What is Software Architecture? :: Chapter 2
Software Architecture - context
“Software architecture is a growing but still young discipline; hence, it has no single, accepted definition”.
“The study of software architecture has evolved by observation of the design principles that designers follow and the actions that they take when working on real systems”.
Bass et al., 2003, pp. 23

4. Software Architecture
The Architecture Business Cycle :: Chapter 1
Software Architecture
Behavior, interaction
implementation, algorithm,
data representation
“The software architecture of a program or computing system is the structure or structures of the system, which comprise software elements, the externally visible properties of those elements, and the relationships among them.” pp. 03

5. Software architecture (cont.)
The Architecture Business Cycle :: Chapter 1
Software architecture (cont.)
If you know the requirements for a system, you can build the architecture for it {try it}

6. The Swedish Ship Vasa The Architecture Business Cycle :: Chapter 1
Sweden x Poland
Features
70m
300 soldiers
64 heavy guns

7. Architecture Business Cycle (ABC)
The Architecture Business Cycle :: Chapter 1
Architecture Business Cycle (ABC)
What is the relationship of a system’s software architecture to the environment in which the system will be constructed and exist?
technical
Architecture
Environment
social
business

8. Architecture The Architecture Business Cycle :: Chapter 1
Business and technical decisions
Games x Web
Influences
Stakeholders
Organization
Skills, schedule, budget
Background and Experience
Patterns, distributed objects, components
Environment

9. Architecture activities
The Architecture Business Cycle :: Chapter 1
Architecture activities
Creating the Business Case for the System
Costs, market, development time
Understanding the requirements
Previous systems, prototypes
Creating or selecting the architecture
Communicating the architecture
Key: Documentation
Analyzing or Evaluating the Architecure
Implementing Based on the Architecture
Ensuring Conformance to an Architecture

10. Architecture - Principles
The Architecture Business Cycle :: Chapter 1
Architecture - Principles
Process recommendations
Single architect x small group
Functional requirements x quality attributes
Documentation
Stakeholder participation
Analysis
Rules of thumb
Information hiding
Separation of concerns
Quality attributes
Non commercial tools

11. What is Software Architecture?

12. Software Architecture
What is Software Architecture? :: Chapter 2
Software Architecture
“If a project has not achieved a system architecture, including its rationale, the project should not proceed to full-scale system development. Specifying the architecture as a deliverable enables its use throughout the development and maintenance process ”.
Barry Boehm [1995]

13. Software Architecture – Some Issues
What is Software Architecture? :: Chapter 2
Software Architecture – Some Issues RS
Mining
Search
Management
But, according to Figure...
What is the nature of the elements?
What are the responsabilities of the elements?
What is the significance of the connections?
What is the significance of the layout?

14. Software Architecture
What is Software Architecture? :: Chapter 2
Software Architecture
The software architecture of a program or computing system is the structure or structures of the system, which comprise software elements, the externally visible properties of those elements, and the relationships among them.
Implementation units
Public aspects
Observed by elements

15. Points of View What is Software Architecture? :: Chapter 2
Architecture is high-level design
Evaluation, documentation, principles
Architecture is the overall structure of the system
Architecture is the structure of the components of a program or system, their interrelationships, and the principles and guidelines governing their design and evolution over time
Process-centered vision
Architecure is components and connectors

16. Well defined architecture....intermediate stages
What is Software Architecture? :: Chapter 2
Well defined architecture....intermediate stages
Architectural pattern
Architect’s first design choice
Architectural style
Reference model {division of funcionality together with data flow between the pieces}
Standard decomposition
Reference model mapped onto software elements
Reference
Model
Reference
Architectural
Software
Architecture
Architectural
Pattern

17. Why Software architecture is important?
What is Software Architecture? :: Chapter 2
Why Software architecture is important?
Communication among stakeholders
Customer, user, project manager, coder, tester
Early design decisions :: architecture:
defines constraints on implementation
dictates Organizational structure
inhibits or enables a system’s quality atributes
makes it easier to reason about and manage change
helps in prototyping, cost and schedule estimates

18. Why Software architecture is important? (cont.)
What is Software Architecture? :: Chapter 2
Why Software architecture is important? (cont.)
Transferable abstraction of a system {reusable model}
Software product lines
Systems can be built using large, externally developed elements
Design pattens :: templates :: training {knowledge transfer}

19. Architecture structures and views
What is Software Architecture? :: Chapter 2
Architecture structures and views
View :: representation of a coherent set of architectural elements, as written by and read by system stakeholders
Composed of: Elements and relation among them
Structure :: set of elements itself
Module {code}
Component-and-connector
Allocation
Ex: module structure x module view

20. Software structures What is Software Architecture? :: Chapter 2
Client-
Server
Process
Shared
data
Concurrency
Component-and-
Connector
Module
Decomposition
Uses
Class
Layered
Work
assignment
Deployment
Implementation
Allocation

21. References
L. Bass, P. C. Clements, R. Kazman. Software Architecture in Practice. Second Edition, Addison-Wesley, 2003.