Coffee Machine Implementation Documentation

Overview

This is a Java-based implementation of a coffee machine simulator that allows users to order different types of coffee, manage resources, and handle transactions. The system is designed with object-oriented principles and follows clean code practices.

Core Components

1. CoffeeMachine Class

The main controller class that manages the coffee machine operations.

Key Features:

• Menu management using HashMap for efficient coffee selection
• Resource tracking
• User interaction handling
• Transaction processing

2. Coffee Class

Represents different types of coffee drinks available in the machine.

Features:

• Builder pattern implementation for flexible coffee creation
• Immutable design to ensure thread safety
• Resource requirements tracking (water, milk, coffee)
• Price information

3. Transactions Class

Handles all monetary transactions and resource management for coffee preparation.

Features:

• Payment processing with support for different coin denominations
• Change calculation
• Resource availability checking
• Coffee preparation process

4. Resources Class

Manages the machine's resources (water, milk, coffee, money).

Features:

• Resource level tracking
• Resource consumption monitoring
• Status reporting
• Batch resource updates

Key Improvements from Original Implementation

1. Code Organization

   • Implemented Builder pattern for Coffee class
   • Centralized menu management
   • Improved error handling
   • Added constant definitions for monetary values

2. Performance Optimizations

   • Reduced object creation in main loop
   • Simplified resource management
   • Improved memory usage with final fields
   • Better scanner management

3. User Experience

   • Enhanced error messages
   • Improved menu display
   • Better formatting of monetary values
   • Clearer resource status display

4. Maintainability

   • Added comprehensive documentation
   • Improved method naming
   • Reduced code duplication
   • Better separation of concerns

Usage Guide

Starting the Machine

CoffeeMachine coffeeMachine = new CoffeeMachine();
coffeeMachine.start();

Adding New Coffee Types

Coffee newCoffee = new Coffee.CoffeeBuilder()
    .name("Mocha")
    .water(200)
    .milk(100)
    .coffee(24)
    .price(3.50)
    .build();

Checking Resources

resources.displayResources();

Best Practices Implemented

1. SOLID Principles

   • Single Responsibility Principle in class design
   • Open/Closed Principle in coffee type additions
   • Interface Segregation in transaction handling

2. Design Patterns

   • Builder Pattern for Coffee class
   • Singleton Pattern for resource management
   • Command Pattern for menu operations

3. Error Handling

   • Graceful handling of insufficient resources
   • Proper transaction validation
   • User input validation