============================================ PROJECT OVERVIEW

This Spring Boot application demonstrates enterprise-grade features with modern development practices. It implements a secure REST API with JWT authentication, email integration, and efficient document processing capabilities while emphasizing cost optimization through JSON node utilization.

============================================ KEY FEATURES

SECURITY:

• JWT authentication with access/refresh tokens
• Role-based authorization using Spring Security
• Custom token validation filters

EMAIL SYSTEM:

• MIME message implementation for HTML emails
• Attachment support for documents/files
• Asynchronous email delivery configuration

API DOCUMENTATION:

• OpenAPI 3/Swagger UI available at /swagger-ui.html
• Integrated JWT support in Swagger interface
• Detailed request/response schema documentation

DATABASE:

• H2 database with file-based persistence
• LOB storage for Excel/Word documents
• SQL initialization scripts in /resources/db

FILE PROCESSING:

• Apache POI integration for Excel/Word generation
• Database storage of generated files as BLOBs
• Batch processing capabilities

SYSTEM OPERATIONS:

• Spring Actuator endpoints (/actuator/*)
• Custom metrics monitoring (email stats, API response times)
• Scheduled tasks with cron expressions

DESIGN PATTERNS:

• Factory pattern implementation for:
  • Multiple response formats (JSON/XML/CSV)
  • Document export handlers
  • Email strategy variations
• Custom exception hierarchy with global handling
• Standardized error response structure

============================================ TECHNOLOGY STACK

• Spring Boot 3.x, Spring Security, Spring Data JPA
• H2 Database (Embedded & Server modes)
• Apache POI 5.x, Jackson Databind
• Spring Actuator, Micrometer
• OpenAPI 3, Swagger UI
• Maven Build System

============================================ SETUP INSTRUCTIONS

1. Configure application.properties: spring.mail.host=your-smtp-host jwt.secret=your-256-bit-secret

2. Run application: mvn spring-boot:run

3. Access endpoints: Swagger UI: http://localhost:8080/swagger-ui.html H2 Console: http://localhost:8080/h2-console Actuator: http://localhost:8080/actuator

4. Authentication: POST http://localhost:8080/api/auth/login Body: {"username":"user","password":"pass"}

============================================ DOCUMENT PROCESSING

• Excel generation using XSSFWorkbook
• Word documents with XWPFDocument
• File storage in database BLOB columns
• Batch operations with Spring Batch

============================================ MONITORING

Custom actuator endpoints:

• /actuator/emailmetrics: Email delivery statistics
• /actuator/apimetrics: API response metrics
• /actuator/scheduledtasks: Cron job statuses

Note: Replace placeholder values (your-smtp-host, your-256-bit-secret) with actual configuration values before running.