Notes

Outline

Software Architecture – Definitions, Roles, and Analogies John D. McGregor Clemson University

Definition from SAP 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.

ANSI/IEEE Std 1471-2000 the fundamental organization of a system, embodied in its components, their relationships to each other and the environment, and the principles governing its design and evolution.

Building Architecture Analogy Similarities    Sense of aesthetics is present in both Differences    Physical laws don’t apply    Software architecture still immature

Leonardo da Vinci – a basic principle

Leonardo da Vinci - observation

Leonardo da Vinci

At last a genuine Leonardo

FallingWater

Christopher Alexander

Grands Magasins du Bon Marche

Quality without a name

Realization hierarchy

Where do I start?

J2EE v. 1.4 architecture

Architecture as a blender of technologies

Block diagram

4+1 Views - Krutchen

Tactics – decomposition - 1

Tactics – decomposition - 2

Tactics – decomposition - 3

Reasoning - Latency attribute

Reasoning – statistical model

Architecture and People Stakeholder – anyone having an interest in the architecture Client User Designers …

Influences on the architecture Stakeholders Developing Organization Technical/Deployment environment Background of architects

Architecture process Understand the requirements Create architectures that satisfy the requirements Evaluate the trade-offs among the architectures Select appropriate architecture Repeat as requirements evolve

Architectural pattern description of element and relation types and a set of constraints Architectural style Client/server – implies multiple clients seeking service from a resource

Reference model Characteristic of the domain – in this case ecommerce

Reference architecture

Why architecture? Communication among stakeholders Early design decisions Transferable abstraction of the system

Architectural Structures Module structures Which piece is responsible for what Component-connector structures how do the major pieces interact at runtime Allocation structures allocates pieces of the architecture to pieces of the external environment

Module structures

Layered example – OSI Protocol Stack

Component/Connector structures

Common Object Request Broker

Allocation structures

Thread architecture

Eclipse environment

Eclipse requirements Edit multiple files Select files Bind files into a project Build a project See the individual attributes