Today we expanded our Library Management System with a reservation feature while deepening our understanding of Git workflows and modern Java features.

The code changes from this session can be found here.

Day 3 Summary

Overview

Started implementing a reservation system for the Library Management System while learning about Git workflows and exploring Java concepts.

Environment & Tools

  • Set up Git with proper .gitignore
  • Created first feature branch for reservation system
  • Learned IDE shortcuts for multiple cursor selection

Concepts Covered

Git Workflow

  • Initial repository setup
  • Multi-line commit messages
  • Feature branching strategy
  • IDE integration with Git

Modern Java Features

  • Records for immutable data (Reservation)
  • Factory methods for object creation
  • Compact constructors with validation
  • Access level considerations in records

Design Patterns & Principles

  • Dependency Injection (constructor injection)
  • Repository pattern continuation
  • Interface design principles
  • Factory method pattern

Java Collections

  • Queue interface and LinkedList implementation
  • HashMap for efficient lookups
  • Collection operations (offer vs add)
  • Stream API for validation

Implementation Progress

  • Created Reservation record with validation
  • Defined ReservationService interface
  • Started InMemoryReservationService implementation
  • Implemented reservation validation logic

Key Takeaways

  • Modern Java features support clean, maintainable code
  • Interface design requires careful consideration of public API
  • Validation should enforce business rules
  • Dependency injection supports loose coupling

Next Steps

Ready to explore:

  • Complete ReservationService implementation
  • Integration with existing borrowing system
  • Exception handling for reservation scenarios
  • Testing the reservation system

Master’s Reflection

The apprentice demonstrated growing comfort with Java’s type system and modern features, while maintaining a keen eye for practical design considerations. The questions about IDE functionality and Git workflows show a holistic approach to learning the Java ecosystem. The intuitive understanding of when to use specific collection types and validation patterns suggests a promising grasp of Java’s strengths.