Batch Transaction Processor with Messaging & Integration – Enterprise Simulation

A mainframe-inspired batch transaction processing system that demonstrates enterprise-grade design, system integration, and messaging patterns. Built with COBOL, JCL, DB2, and simulated messaging workflows, this project mimics real-world banking batch processing and inter-system communication, all runnable in a personal development environment.

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Project Overview

This system simulates real-world banking batch workflows with integrated messaging:

• Processes daily financial transactions from multiple sources
• Validates and reconciles transactions for account integrity
• Updates DB2 tables safely with transactional guarantees
• Generates audit and reconciliation reports
• Demonstrates integration patterns such as messaging, queues, and batch orchestration between systems

This project shows mainframe + integration skills, including:

• Transaction rollback and error handling
• COBOL modular design
• Batch job orchestration via JCL
• Messaging and inter-system communication simulation

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Enterprise-Grade Features

• Batch Job Scheduling: Sequential and conditional batch job execution simulating nightly bank operations

• Transaction Safety & Rollback: Ensures failed transactions do not corrupt data

• DB2 Integration: Normalized tables for accounts and transactions

• Messaging & Integration:

  • Simulated message queues for incoming transactions (could be implemented with JMS, MQ, or even files for demo purposes)
  • Batch jobs consume messages and update DB2 tables
  • Failure handling with retry mechanisms and dead-letter queues

• Modular COBOL Design: Separate modules for input parsing, transaction processing, messaging, and reporting

• Audit & Observability: Tracks processed messages, batch status, errors, and reconciliations

• Error Handling & Recovery: Detects invalid transactions, logs them, and retries message processing

• Scalability Considerations: Architecture supports multiple input sources and message adapters

• Compliance-Ready Simulation: Demonstrates batch integrity, audit logging, and messaging reliability aligned with enterprise practices

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Skills Demonstrated

• Enterprise batch processing and job scheduling
• Transaction validation and rollback logic
• COBOL modular programming
• DB2 schema design and integration
• Messaging & queue patterns (simulated MQ or file-based queues)
• Audit logging and error handling
• Hybrid mainframe + modern tooling (VS Code, Git, Zowe CLI/Explorer)
• Inter-system integration thinking

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Getting Started

1. Clone the repository and set up your local DB2 instance

2. Follow project documentation for:

   • Batch job submission
   • Transaction processing workflow
   • Message queue simulation and consumption
   • Audit and reconciliation reporting

3. All datasets are dummy data, safe for testing and sharing

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Project Structure

• cobol/ – COBOL programs for transaction processing, messaging adapters, and reporting
• jcl/ – Batch job scripts orchestrating job flow and message consumption
• db2/ – DB2 schemas and sample data
• data/ – Dummy transaction input files and simulated message queues
• docs/ – Architecture diagrams, workflow documentation, and instructions

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Integration & Messaging Overview

1. Incoming transactions are delivered via simulated message queues

2. COBOL batch jobs consume messages sequentially or in parallel

3. Each message triggers:

   • Validation of transaction data
   • DB2 table updates
   • Audit log entries

4. Failed messages go into retry or dead-letter queues

5. Reporting jobs aggregate successful and failed transactions for review

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Contributing

• Add new message adapters or queue types
• Enhance error handling and retry logic
• Improve batch orchestration or reporting

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License

MIT License

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