[FEATURE] Implement WithFieldName interface for QueryBuilder implementations in plugins

[dzane17]

Is your feature request related to a problem?

The Query Insights plugin utilizes the field name attribute in QueryBuilder objects to generate query shape. However, not all query types have a field name or a query may operate on multiple fields. To solve this, we created the WithFieldName interface to tag QueryBuilder implementations which contain a single field name.

Parent Issue: opensearch-project/query-insights#110

What solution would you like?

This plugin was identified to contain one or more applicable QueryBuilders. Please check for classes which meet the criteria and make the requisite changes.

• Search for "extends AbstractQueryBuilder" inside the plugin repo to find candidate classes
• If this query builder operates on a single field: 1) add extends WithFieldName & 2) override interface method fieldName() to return field name as String

Example KNN PR: opensearch-project/k-NN#2398

What alternatives have you considered?

A clear and concise description of any alternative solutions or features you've considered.

Do you have any additional context?

Add any other context or screenshots about the feature request here.

[martin-gaievski]

@dzane17 what is expected behavior in case of compound query? Such query operates at multiple nested child sub-queries and does not have a single field name. We do have such query in neural search repo, it's hybrid query, check out example here. It's very similar structurally to Bool query.

[dzane17]

@martin-gaievski These query types can be skipped, as Query Insights does not extract field names from multi-field queries.