III-527 Create dedicated database connection checker

[lucwollants]

Changed

• Created dedicated database connection checker

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Ticket: https://jira.uitdatabank.be/browse/III-527

[lucwollants]

@claude please review

[claude]

Summary

This is a well-executed refactoring that extracts database connection checking logic into a dedicated, reusable component. The changes follow SOLID principles by creating a focused interface and implementation.

Strengths ✅

1. Clean separation of concerns: The DatabaseConnectionChecker interface and DBALDatabaseConnectionChecker implementation properly separate connection management from business logic
2. Excellent test coverage: The new DBALDatabaseConnectionCheckerTest covers all three scenarios (healthy, reconnection success, reconnection failure)
3. Proper test migration: Tests were correctly moved from EventBusForwardingConsumerTest to the new dedicated test class
4. Better reusability: The checker can now be used by other consumers without code duplication
5. Logging preserved: All debug, warning, and critical logging behavior is maintained

Suggestions for Improvement 🔍

1. Error handling: Consider how reconnection failures should be communicated to callers (currently silent after logging)
2. Performance: Running SELECT 1 on every message may be overkill - consider periodic checking or reactive checking only after failures
3. Documentation: Add docblocks to clarify the interface contract and expected behavior
4. Minor style fix: String should be lowercase string in the constructor parameter

Architecture Notes

The refactoring successfully:

• Removes 29 lines from EventBusForwardingConsumer and adds 40 lines in the new dedicated class (net positive for maintainability)
• Creates a testable boundary via the interface
• Makes the service provider slightly more verbose but clearer in dependencies
• Enables future connection checkers for different database types if needed

Overall, this is a solid refactoring that improves code organization and testability. The suggestions above are enhancements to consider, not blockers.

[grubolsch]

Thanks for looking into this, and great job adding some tests!