Add Prefix and Wildcard Query Support to DSL Query Executor

[abhishek00159]

Summary

Implements PrefixQueryTranslator and WildcardQueryTranslator that convert OpenSearch prefix and wildcard queries to Calcite LIKE expressions with full support for case-insensitive matching and proper SQL special character
escaping.

Features

Prefix Query

Converts prefix queries to SQL LIKE with trailing wildcard:

json
{"prefix": {"name": "lap"}}
// Converts to: name LIKE 'lap%'

{"prefix": {"name": {"value": "LAP", "case_insensitive": true}}}
// Converts to: LOWER(name) LIKE 'lap%'

Supported parameters:
• value - The prefix string
• case_insensitive - Case-insensitive matching (default: false)

Unsupported parameters (throw ConversionException):
• boost - Query boosting not supported
• rewrite - Rewrite method not supported

Wildcard Query

Converts wildcard patterns to SQL LIKE with pattern translation:

json
{"wildcard": {"name": "lap*"}}
// Converts to: name LIKE 'lap%'

{"wildcard": {"name": "l?ptop"}}
// Converts to: name LIKE 'l_ptop'

{"wildcard": {"name": {"value": "BOOK", "case_insensitive": true}}}
// Converts to: LOWER(name) LIKE '%book%'

Wildcard characters:
• * - Matches any character sequence → SQL %
• ? - Matches any single character → SQL _

Supported parameters:
• value - The wildcard pattern
• case_insensitive - Case-insensitive matching (default: false)

Unsupported parameters (throw ConversionException):
• boost - Query boosting not supported
• rewrite - Rewrite method not supported

Special Character Escaping

Both translators properly escape SQL LIKE special characters:
• % → % (SQL wildcard for any characters)
• _ → _ (SQL wildcard for single character)
• \ → \ (escape character)

Example:
json
{"prefix": {"path": "C:\test_"}}
// Converts to: path LIKE 'C:\\test\_%'

{"wildcard": {"name": "a%b_c\d*"}}
// Converts to: name LIKE 'a%b_c\\d%'

Case Insensitive Support

When case_insensitive: true:
• Applies LOWER() function to field reference
• Converts pattern to lowercase
• Works for both prefix and wildcard queries

Examples

Prefix in Bool Query

json
{
"bool": {
"must": [{"prefix": {"category": "electron"}}],
"should": [
{"prefix": {"brand": "sam"}},
{"prefix": {"brand": "app"}}
]
}
}

Converts to: (category LIKE 'electron%') AND ((brand LIKE 'sam%') OR (brand LIKE 'app%'))

Complex Wildcard Pattern

json
{"wildcard": {"sku": "-2021-"}}

Converts to: sku LIKE '%-2021-%'

Testing

Unit Tests:
• tests for PrefixQueryTranslator
• tests for WildcardQueryTranslator
• Coverage: basic patterns, case sensitivity, escaping, edge cases, error handling

Integration Tests:
• End-to-end validation with real index data for DslPrefixQueryIT
• End-to-end validation with real index data for DslWildcardQueryIT

Documentation

Implementation Docs:
•Updated README.md file for supported queries.

Technical Notes

• Both translators validate field existence in schema
• Throw ConversionException for unsupported parameters (boost, rewrite)
• Character escaping performed before wildcard conversion to prevent conflicts
• Case-insensitive queries use SQL LOWER() function
• Registered in QueryRegistryFactory for O(1) lookup

Performance Considerations

• LIKE patterns with leading characters are generally efficient
• Case-insensitive queries using LOWER() may not use indexes effectively
• Wildcard patterns starting with * may require full table scans

Related Issues

Resolves #[Issue number to be closed when this PR is merged]

Check List

• [ YES ] Functionality includes testing.
• [ YES ] API changes companion pull request created, if applicable.
• [ NA ] Public documentation issue/PR created, if applicable.

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