MBA-716: Extract Look.java business logic into LookService

[devin-ai-integration]

MBA-716: Extract Look.java business logic into LookService

Summary

This PR refactors the Look.java CLI tool to extract its core business logic into a new LookService class, establishing the first service layer in the codebase as part of the microservices architecture conversion (parent epic).

Key Changes:

• Created LookService class in new gov.uspto.bulkdata.service package with three core methods:
  • lookupPatents() - processes multiple patents with a limit
  • lookupPatentById() - looks up a specific patent by document ID
  • showPatentFields() - extracts and formats patent fields (private helper)
• Made the service stateless by passing rawDoc as a parameter instead of using instance variables
• Refactored Look.java to use LookService as a thin CLI wrapper (removed ~180 lines of business logic)
• Added Mockito test dependency to BulkDownloader module
• Created comprehensive test suites:
  • LookServiceTest.java - 6 unit tests covering core service methods
  • LookIntegrationTest.java - 8 integration tests verifying CLI functionality
• All 24 BulkDownloader tests passing

Behavior Preservation:

• CLI interface unchanged (same arguments, same output format)
• All 12 field types supported: raw, id, title, abstract, description, claims, citations, assignee, inventor, classification, object, family
• Error handling preserved (NoSuchElementException catching, PatentReaderException propagation)
• MDC logging context maintained

Review & Testing Checklist for Human

⚠️ Risk Level: YELLOW - Pure refactoring with comprehensive tests, but limited testing with real patent data

• Test with real USPTO patent files - The automated tests use synthetic XML documents. Please test the CLI with actual patent bulk files (Greenbook, SGML, PAP, Red Book XML formats) to verify all field extractions work correctly across different formats
• Verify ID lookup functionality - Test lookupPatentById with real patent IDs to ensure the document ID matching works correctly (the tests verify the method runs but don't fully validate ID matching behavior)
• Spot check output format - Run the CLI with various field combinations and compare output to the original implementation to ensure formatting is identical

Recommended Test Plan:

# Test with a real patent file
cd ~/repos/USPTO-Patent-Public-Data
java -cp "BulkDownloader/target/classes:..." gov.uspto.bulkdata.cli.Look \
  --source="download/ipg240102.zip" \
  --fields="id,title,abstract" \
  --limit=5

# Test ID lookup
java -cp "BulkDownloader/target/classes:..." gov.uspto.bulkdata.cli.Look \
  --source="download/ipg240102.zip" \
  --id="US12345678B2" \
  --fields="id,title"

# Test all field types
java -cp "BulkDownloader/target/classes:..." gov.uspto.bulkdata.cli.Look \
  --source="download/ipg240102.zip" \
  --fields="raw,id,title,abstract,description,claims,citations,assignee,inventor,classification,object,family" \
  --limit=1

Notes

• This establishes the architectural pattern for future service extractions as the codebase moves toward microservices
• The service interface is designed to be reusable for future REST APIs
• Pre-existing test failures in PatentDocument module (3 failures) are unrelated to these changes
• Session: https://app.devin.ai/sessions/f192f3e120364b6db3b4133d5b523e5f
• Requested by: Jake Cosme (jake@cognition.ai) / @jakexcosme

[devin-ai-integration]

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