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Software Architecture(SWA)

Interview of Nenad Medvidovic​

Software Architecture: Foundations, Theory, and Practice 2009. Wiley, ISBN 978-0-470-16774-8

Software Erosion​

What's is software Architecture?​

Perry and Wolf SWA = {Elements(What), Form(How), Rationale(why)}

Shaw and Garland. SWA is a level of design that involves

  • Description of elements from which systems are built
  • Interactions among those elements
  • Patterns that guide their composition
  • Constraints on these patterns

A general definition of SWA​

A Set of principal design decisions about the system.

Prescriptive Architecture​

It captures the design decisions prior to the system's construction. As-Conceived SWA.

Prescriptive Arch should be modified first. However, this rarely happens.

  • Developers' sloppiness
  • Short deadlines
  • Lack of documented prescriptive architecture.

Descriptive Architecture​

It describes how the system has actually been built. As implemented SWA.

Architectural Degradation​

Arch drift​

Introduced orthogonal decisions to a system's prescriptive architecture.

Arch erosion​

Introduced decisions violated a system's prescriptive architecture.

Linux Kernel example

Arch. Elements​

A software architecture typically is not a monolith.

Elements Metaphors

Components​

  • Processing elements: implement business logic and perform transformation on data.
  • Date elements (information/state): elements contained information that is used in processing elements.

Software Components​

  • Encapsulates a subset of the system's functionality and/or data.
  • restrict access to that subset via an explicitly defined interface.

Connectors​

  • Interaction elements: glue that holds different pieces together.

Software connector: architectural entity affecting and regulating interaction​

Arch. configuration​

Association between components and connectors of a software architecture.

Architecture styles​

  • Pipe and filters: Unix commands,
  • Event Driven: GUI
  • Publish-subscribe: Twitter
  • Client-Server : email
  • Peer-to-peer
  • REST