FIT2099_MOC

📘 FIT2099: Object-Oriented Design and Implementation

Map of Content

Index for FIT2099 Object-Oriented Design and Implementation (Java). Every design note carries a Mermaid classDiagram; designs are judged on Coupling / Cohesion / Extensibility. Start with OOP Building Blocks (Class, Object, Field, Method).

📊 Assessment Map

• Assessment: engine-based Java group project across milestones + individual work.
• Assessed skills: design rationale in Coupling/Cohesion/Extensibility terms, UML/Mermaid diagrams, SOLID application, smell → refactor.

🧰 Toolkit Cheatsheets

• 📌 FIT2099 Unit Cheatsheet — principles, smells→refactors, contracts, UML rules
• Java Toolkit (Cheatsheet) — code a class from a blank editor: class anatomy, modifiers, types/==-vs-equals, collections, inheritance/polymorphism/interfaces/enums, exceptions/DbC/CQS, DI/defensive copying, Factory Method, and the smell→refactoring quick-map.
• UML Toolkit (Cheatsheet) — draw from a blank page: class-diagram compartments/visibility/relationship-arrow legend/multiplicity/stereotypes, sequence-diagram lifelines/messages/activation/fragments, and the domain/activity/use-case/CRC modelling tools (Mermaid syntax throughout).

📅 Knowledge Index

Week 1 — Java & OO Fundamentals

• Java Static Typing → Parent Framework: Java Program Structure
• Java Program Structure → Parent Framework: OOP Building Blocks (Class, Object, Field, Method)
• OOP Building Blocks (Class, Object, Field, Method) → Parent Framework: Java Program Structure
• Java Data Types, Casting and References → Parent Framework: OOP Building Blocks (Class, Object, Field, Method)
• Java Constructors → Parent Framework: OOP Building Blocks (Class, Object, Field, Method)
• Java Control Flow (Conditionals and Loops) → Parent Framework: Java Program Structure
• Java Arrays → Parent Framework: Java Program Structure
• Client-Supplier Relationship (Java) → Parent Framework: OOP Building Blocks (Class, Object, Field, Method)

Week 2 — Modifiers, UML Relationships, Design Principles & Inheritance

• Java Packages and Imports → Parent Framework: Java Program Structure
• Encapsulation and Access Modifiers (Java) → Parent Framework: OOP Building Blocks (Class, Object, Field, Method)
• Static and Final (Java) → Parent Framework: OOP Building Blocks (Class, Object, Field, Method)
• UML Associations and Dependencies (Java) → Parent Framework: Client-Supplier Relationship (Java)
• Three Core Design Principles (Java) → Parent Framework: Client-Supplier Relationship (Java)
• Inheritance (Java) → Parent Framework: OOP Building Blocks (Class, Object, Field, Method)

Week 3 — Collections, Polymorphism & Abstraction

• Java Collections (List, Set, Map) → Parent Framework: Java Arrays
• Polymorphism (Java) → Parent Framework: Inheritance (Java)
• Abstract Classes (Java) → Parent Framework: Inheritance (Java)
• (deepened this week: Static and Final (Java) — static↔instance access matrix, why-use/why-carefully; Encapsulation and Access Modifiers (Java) — encapsulation boundaries & ReD; Java Packages and Imports — module-info.java)

Week 4 — Interfaces & Enumerations

• Interfaces (Java) → Parent Framework: Abstract Classes (Java)
• Enumerations (Java) → Parent Framework: Three Core Design Principles (Java)
• (deepened this week: Java Data Types, Casting and References — == (identity) vs .equals() (value) & the String Pool)

Week 5 — SOLID Principles

• SOLID Principles (Java) → Parent Framework: Three Core Design Principles (Java) (hub: overview table, ReD, LCOM, downcasting/instanceof)
• Single Responsibility Principle (Java) → Parent Framework: SOLID Principles (Java)
• Open-Closed Principle (Java) → Parent Framework: SOLID Principles (Java)
• Liskov Substitution Principle (Java) → Parent Framework: SOLID Principles (Java)
• Interface Segregation Principle (Java) → Parent Framework: SOLID Principles (Java)
• Dependency Inversion Principle (Java) → Parent Framework: SOLID Principles (Java)

Week 6 — Applying Abstraction: Injection, Copying & Rationale

• Dependency Injection (Java) → Parent Framework: Dependency Inversion Principle (Java)
• Defensive Copying (Java) → Parent Framework: Encapsulation and Access Modifiers (Java)
• Design Rationale (FIT2099) → Parent Framework: SOLID Principles (Java) (⭐ Assignment 1 writing artefact)
• (deepened this week: Dependency Inversion Principle (Java) — hinge point + DI link; Encapsulation and Access Modifiers (Java) — abstraction-layer sizing & connascence)

Week 7 — Dynamic Modelling

• UML Sequence Diagrams (Java) → Parent Framework: UML Associations and Dependencies (Java) (⭐ Assignment interaction diagrams)

Week 8 — Design by Contract, Exceptions & Factory

• Design by Contract (Java) → Parent Framework: Client-Supplier Relationship (Java)
• Command-Query Separation (Java) → Parent Framework: Design by Contract (Java)
• Exceptions, Assertions and Validation (Java) → Parent Framework: Design by Contract (Java)
• Factory Method Pattern (Java) → Parent Framework: Abstract Classes (Java) (first GoF pattern)
• (deepened this week: Liskov Substitution Principle (Java) — the DbC subcontracting formulation, weaker-pre/stronger-post)

Week 9 — Code & Design Smells + Refactoring

• Design Smells (Java) → Parent Framework: SOLID Principles (Java) (smell catalogue + smell→refactoring map)
• Refactoring (Java) → Parent Framework: Design Smells (Java)

Week 10 — Refactoring to Address Code Smells

• (deepened this week: Refactoring (Java) — the refactor-to-enable-change motivation (Fowler statement() scenario) + the identify→fix→apply→test→commit→repeat loop; no new note — Week 10 is a worked deepening of the Week 9 material.)

Week 11 — Design in the Lifecycle, Technical Debt & the Design Process

• Software Design in the Lifecycle (FIT2099) → Parent Framework: FIT2099_MOC (when/why to design; SDLC + Lean)
• Technical Debt (FIT2099) → Parent Framework: Refactoring (Java)
• Design Process and Techniques (FIT2099) → Parent Framework: Software Design in the Lifecycle (FIT2099) (how to design)
• CRC Cards (FIT2099) → Parent Framework: Design Process and Techniques (FIT2099)

📐 UML Notation References (consolidated)

• UML Class Diagrams (Java) — the static notation legend (visibility marks, stereotypes, full arrow table + multiplicity — gathers syntax taught piecemeal across W2–4)
• UML Sequence Diagrams (Java) — the dynamic notation legend (see Week 7).

🧭 Suggested Reading Order

(read left→right within each week · bold = assignment-critical; ⭐ = graded artefact skill)

• W1 — Java foundations: Java Static Typing → Java Program Structure → OOP Building Blocks (Class, Object, Field, Method) → Java Data Types, Casting and References → Java Constructors → Java Control Flow (Conditionals and Loops) → Java Arrays → Client-Supplier Relationship (Java) → Java Packages and Imports
• W2 — encapsulation & first principles: Encapsulation and Access Modifiers (Java) → Static and Final (Java) → UML Associations and Dependencies (Java) (association/dependency/inheritance only) → Three Core Design Principles (Java) → Inheritance (Java)
• W3 — polymorphism & abstraction: Java Collections (List, Set, Map) → Polymorphism (Java) → Abstract Classes (Java)
• W4 — capability contracts: Interfaces (Java) → Enumerations (Java)
• W5 — SOLID: SOLID Principles (Java) (hub) → Single Responsibility Principle (Java) → Open-Closed Principle (Java) → Liskov Substitution Principle (Java) → Interface Segregation Principle (Java) → Dependency Inversion Principle (Java)
• W6 — applied abstraction: Dependency Injection (Java) → Defensive Copying (Java) → ⭐ Design Rationale (FIT2099) (the A1 justification artefact)
• W7 — dynamic modelling: ⭐ UML Sequence Diagrams (Java) (concrete classes only)
• W8 — contracts: Design by Contract (Java) → Command-Query Separation (Java) → Exceptions, Assertions and Validation (Java) → Factory Method Pattern (Java)
• W9–10 — smells & refactoring: Design Smells (Java) (smell → refactoring map) → Refactoring (Java) (behaviour-preserving, two hats)
• W11 — design process & meta: Software Design in the Lifecycle (FIT2099) → Technical Debt (FIT2099) → Design Process and Techniques (FIT2099) → CRC Cards (FIT2099)

🎯 Learning Outcomes

Unit LOs:

1. design with UML (class + interaction diagrams)
2. judge design quality
3. implement abstraction/information-hiding/inheritance/polymorphism in Java
4. refactor + debug
5. practise with IDEs, UML tools, version control

Key skills per week:

• W1 ➔
  • static typing catches errors at compile time
  • class = blueprint, object = instance
  • value vs reference semantics
  • constructors, control flow, arrays
  • client couples to the interface only (LO3)
• W2 ➔
  • private fields + deliberate accessors
  • static = class-level, final = assign-once (reference ≠ immutable)
  • draw association vs dependency vs inheritance arrows
  • DRY / own-your-properties / no magic literals (LO1–3)
• W3 ➔
  • program to the collection interface (wrapper types in generics)
  • runtime type dispatches the override, declared type limits visibility
  • abstract = never instantiated (LO3)
• W4 ➔
  • one extends, many implements — capability contracts
  • enums kill magic-number smells with compile-time checks (LO3)
• W5 ➔
  • argue every design decision through SRP/OCP/LSP/ISP/DIP
  • principles are guidelines — over-application is its own smell (LO1–2)
• W6 ➔
  • inject collaborators from outside (DI beyond DIP)
  • defensive-copy mutable state at boundaries
  • write rationale = WHY + alternative + trade-off, never description (LO1–3, A1)
• W7 ➔
  • sequence diagram one narrow scenario, concrete classes only, correct message/activation notation (LO1, A1)
• W8 ➔
  • precondition breach = client bug (exception), postcondition = supplier bug (assertion)
  • commands vs queries
  • Factory Method returns the parent type (LO2–3)
• W9–10 ➔
  • recognise smell families as hints not proofs
  • type-branching → Replace Conditional with Polymorphism
  • refactor behaviour-preserving under tests, two hats (LO4)
• W11 ➔
  • decide as late as responsibly possible (Lean)
  • take technical debt deliberately + repay by refactoring to better design
  • explore with CRC cards, split when the card overflows (LO1, LO5)