Development Patterns for Long-Term Financial Applications

Financial applications often involve long-running processes, which can span days or even weeks. Implementing development patterns that support these extended workflows is crucial.

Saga Pattern

The Saga pattern helps manage long-running transactions by breaking them into smaller, manageable steps with compensating actions to handle failures.

public class LoanProcessingSaga {
    public void applyForLoan(LoanApplication application) {
        try {
            // Step 1: Validate application
            validateApplication(application);

            // Step 2: Process application
            processApplication(application);

            // Step 3: Approve loan
            approveLoan(application);
        } catch (Exception e) {
            // Compensating action
            rollbackApplication(application);
        }
    }

    private void validateApplication(LoanApplication application) {
        // Validation logic
    }

    private void processApplication(LoanApplication application) {
        // Processing logic
    }

    private void approveLoan(LoanApplication application) {
        // Approval logic
    }

    private void rollbackApplication(LoanApplication application) {
        // Rollback logic
    }
}

Event-Driven Architecture

Using an event-driven architecture with Apache Kafka, we can handle long-running processes by decoupling services and using events to trigger actions.

@Service
public class LoanApplicationService {
    @Autowired
    private KafkaTemplate<String, LoanApplicationEvent> kafkaTemplate;

    public void applyForLoan(LoanApplication application) {
        // Publish loan application event
        kafkaTemplate.send("loan-application-events", new LoanApplicationEvent(application));
    }
}

@Component
public class LoanApplicationEventListener {
    @KafkaListener(topics = "loan-application-events", groupId = "loan-processing")
    public void handleLoanApplicationEvent(LoanApplicationEvent event) {
        // Handle event
        processLoanApplication(event.getApplication());
    }

    private void processLoanApplication(LoanApplication application) {
        // Processing logic
    }
}

For more details, related to these prototyping efforts, check out Logging, Tracking, and more with Spring Boot related to this work.