Admin Stuff

• Assignment 1 marks will be released
  • You can view feedback on the FEEDBACK branch on your repo
  • If you have any issues with the automarking, please read Sai's post on WebCMS

Admin Stuff

• There will be an in-person sample exam in Week 10 using the exam environment. 
  • The aim is for you to get familiar with the exam environment, layout and format for the exam. 

Software Architecture

Software Architecture

Software architecture defines the fundamental structure of a software system.

• It defines how system components are structured, how they interact

Why is it important to learn software architecture?

Influences software's adaptability, scalability, performance and maintainability

Sequence Diagrams

Diagram that shows interactions between objects and overall behaviour of the system overtime

Benefits

Structure and Key components

Lifelines: shows object existence during interactions

Messages: Communication between objects

Activation boxes: indicates active processing of messages

• Horizontal axis represents objects
  • ​Objects placed left to right
  • The order represents the message sequence

• Vertical axis represents time
  • ​Time flows downward
  • Sequence diagrams prioritise order, not duration
  • Therefore, vertical spacing does not represent any sort of time intervals

• Messages are horizontal arrows
  • Can be calls/invocations for some methods in a component
  • Can be results given by that component

• Activation boxes (vertical rectangles) represents execution

Types of Messages

Synchronous

Asynchronous

Activation box exists so the message is processed immediately

No activation box so message processing and response is delayed

Sequence diagram demo on Excalidraw and Mermaid

C4 Model

C4 Model

• A model to visualise and document software architecture in an intuitive visual manner
• Uses different levels of abstraction to bridge the gap between high-level overviews and low-level code details

Different C4 Levels

What is the C4 Model? What is its purpose?

• System context level
• Containers level
• Components level
• Code level

System context level

• Shows overall system along with users and other external systems
• Helps to describe scope of the project and determine what problem is being solved and who the users are
• Intended for business stakeholders, execs and non-tech users

Container level

• Describes the physical components of the system (APIs, databases)
• Each application or service is represented by a container and interactions are shown at a high-level
• Intended for developers, tech leads and architects

Component level

• Represents abstractions of the codebase
• Shows modules/classes within a container
• Mainly for developers

Code level

• Show how the code of a component is implemented
• Can use a UML diagram to describe the component

C4 Demo on Excalidraw