Improve Fess Ingest feature implementation

[marevol]

…st coverage

This commit introduces comprehensive improvements to the ingest module:

IngestFactory improvements:

• Replace array-based storage with ArrayList for better performance
• Add caching mechanism with volatile array for efficient concurrent reads
• Implement automatic deduplication (same class replacement)
• Add new methods: remove(), removeByClass(), clear(), size()
• Improve thread-safety with proper synchronization
• Add null validation and defensive copying
• Enhance logging with priority information

Ingester improvements:

• Add priority validation with MIN/MAX/DEFAULT constants (0-999 range)
• Implement equals() and hashCode() based on class type
• Add toString() for better debugging
• Improve Javadoc with detailed parameter descriptions
• Add IllegalArgumentException for invalid priority values

Test coverage improvements:

• IngestFactoryTest: Add 12+ comprehensive test cases covering:
  • Sorting, deduplication, null handling
  • Remove operations, clear, size
  • Defensive copying, concurrent scenarios
• IngesterTest: Replace placeholder tests with 15+ real test cases:
  • Priority validation and edge cases
  • All process() method variants
  • equals/hashCode contracts
  • Custom processing implementations

These improvements enhance code maintainability, reliability, and make the ingest module more robust for production use.

[Copilot]

Pull Request Overview

This PR significantly enhances the Fess ingest module by improving implementation robustness, thread-safety, and test coverage. The changes transform placeholder tests into comprehensive test suites and add key functionality to the factory and ingester classes.

Key Changes:

• Replaced array-based storage with ArrayList in IngestFactory and implemented caching for better performance
• Added priority validation, equals/hashCode methods, and enhanced documentation to Ingester
• Created comprehensive test suites with 15+ tests for IngesterTest and 12+ tests for IngestFactoryTest

Reviewed Changes

Copilot reviewed 4 out of 4 changed files in this pull request and generated 2 comments.

File	Description
src/test/java/org/codelibs/fess/ingest/IngesterTest.java	Replaced placeholder tests with comprehensive test coverage for priority validation, process methods, equals/hashCode, and custom implementations
src/test/java/org/codelibs/fess/ingest/IngestFactoryTest.java	Added extensive tests for factory operations including sorting, deduplication, removal, and defensive copying
src/main/java/org/codelibs/fess/ingest/Ingester.java	Added priority constants and validation, implemented equals/hashCode/toString methods, and enhanced documentation
src/main/java/org/codelibs/fess/ingest/IngestFactory.java	Refactored to use ArrayList with caching, added removal operations, and improved thread-safety and logging

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[Copilot]

The method claims to return a defensive copy but returns the cached array directly. Since arrays are mutable, callers could modify the internal state. Return cachedIngesters.clone() to ensure a true defensive copy.

Suggested change

	// Return the cached array (already a copy from toArray)
	return cachedIngesters;
	// Return a defensive copy of the cached array
	return cachedIngesters.clone();

[Copilot]

This test creates a new TestIngester instance which won't match the existing instance in the factory since equals() is based on class type only. The remove() method uses List.remove() which relies on equals(). This test should fail unless the existing ingester has priority 2, but the comment suggests it's testing removal of a non-existent ingester. Either use the same instance or verify the test behavior matches the intent.

Suggested change

	boolean removed = factory.remove(new TestIngester(2));
	boolean removed = factory.remove(new AnotherTestIngester(2));