Invoice Subsystem - Very Good Building & Development Company (VGB)

Overview

This document provides the technical design for the Invoice Subsystem of Very Good Building & Development Company (VGB), Ron Swanson's company. VGB is a construction company involved in various aspects of the industry, including:

• General contracting
• Subcontracting
• Sales
• Leasing and rental of construction equipment and materials

The system modernizes VGB's invoice management process by replacing spreadsheets and physical records with a robust database-backed solution. Built as an object-oriented Java application, it handles diverse transaction types with specific tax rules and calculation models.

Key Features

• Multi-transaction support: Equipment purchases/leases/rentals, Material purchases, Contract services
• Calculations: Specialized pricing models and tax calculations based on transaction type
• Database integration: MySQL backend with JDBC connection management
• Report generation: Summary reports, customer-specific reports, detailed invoice reports

System Design

The Invoice Subsystem is designed as an object-oriented application written in Java. It integrates:

• Object-oriented design with appropriate inheritance relationships
• JDBC database connectivity for data persistence
• Well-defined data models representing business entities

Technology Used

• Java
• JDBC (Java Database Connectivity)
• MySQL
• JUnit (for testing)
• Log4j (for logging)

Technical Specifications

This document outlines the following key aspects required for implementing the Invoice Subsystem:

• Data Models: Defining structured representations of invoices and related entities
• System Architecture: Object-oriented design principles with a database-backed infrastructure
• Technical Implementation: Details on database integration, API design, and data exchange formats

Future Enhancements

As the system evolves, future improvements may include:

• Integrate a custom sorted list ADT to replace existing data structures.
• Maintain invoice ordering by total amount, customer name, and total per customer.
• Ensure ordering is maintained internally—no external sorting allowed.
• Design the list to be generic and accept a Comparator at instantiation.
• Update the application to use the new list ADT for report generation.
• Improve API methods in for data manipulation via JDBC.

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