update fieldNames to accomodate per field boosting from now

Author: Samiul-TheSoccerFan

x-pack/plugin/inference/src/main/java/org/elasticsearch/xpack/inference/queries/SemanticKnnVectorQueryRewriteInterceptor.java

@@ -33,10 +33,10 @@ public class SemanticKnnVectorQueryRewriteInterceptor extends SemanticQueryRewri
     public SemanticKnnVectorQueryRewriteInterceptor() {}
 
     @Override
-    protected String getFieldName(QueryBuilder queryBuilder) {
+    protected Map<String, Float> getFieldNamesWithWeights(QueryBuilder queryBuilder) {
         assert (queryBuilder instanceof KnnVectorQueryBuilder);
         KnnVectorQueryBuilder knnVectorQueryBuilder = (KnnVectorQueryBuilder) queryBuilder;
-        return knnVectorQueryBuilder.getFieldName();
+        return Map.of(knnVectorQueryBuilder.getFieldName(), 1.0f);
     }
 
     @Override

x-pack/plugin/inference/src/main/java/org/elasticsearch/xpack/inference/queries/SemanticMatchQueryRewriteInterceptor.java

@@ -12,6 +12,8 @@
 import org.elasticsearch.index.query.MatchQueryBuilder;
 import org.elasticsearch.index.query.QueryBuilder;
 
+import java.util.Map;
+
 public class SemanticMatchQueryRewriteInterceptor extends SemanticQueryRewriteInterceptor {
 
     public static final NodeFeature SEMANTIC_MATCH_QUERY_REWRITE_INTERCEPTION_SUPPORTED = new NodeFeature(
@@ -21,10 +23,10 @@ public class SemanticMatchQueryRewriteInterceptor extends SemanticQueryRewriteIn
     public SemanticMatchQueryRewriteInterceptor() {}
 
     @Override
-    protected String getFieldName(QueryBuilder queryBuilder) {
+    protected Map<String, Float> getFieldNamesWithWeights(QueryBuilder queryBuilder) {
         assert (queryBuilder instanceof MatchQueryBuilder);
         MatchQueryBuilder matchQueryBuilder = (MatchQueryBuilder) queryBuilder;
-        return matchQueryBuilder.fieldName();
+        return Map.of(matchQueryBuilder.fieldName(), 1.0f);
     }
 
     @Override

x-pack/plugin/inference/src/main/java/org/elasticsearch/xpack/inference/queries/SemanticQueryRewriteInterceptor.java

@@ -33,7 +33,12 @@ public SemanticQueryRewriteInterceptor() {}
 
     @Override
     public QueryBuilder interceptAndRewrite(QueryRewriteContext context, QueryBuilder queryBuilder) {
-        String fieldName = getFieldName(queryBuilder);
+        Map<String, Float> fieldNamesWithWeights = getFieldNamesWithWeights(queryBuilder);
+        if (fieldNamesWithWeights.size() > 1) {
+            // Multi-field query, so return the original query, and an exception will be thrown eventually
+            return queryBuilder;
+        }
+        String fieldName = fieldNamesWithWeights.keySet().iterator().next();
         ResolvedIndices resolvedIndices = context.getResolvedIndices();
 
         if (resolvedIndices == null) {
@@ -59,9 +64,10 @@ public QueryBuilder interceptAndRewrite(QueryRewriteContext context, QueryBuilde
 
     /**
      * @param queryBuilder {@link QueryBuilder}
-     * @return The singular field name requested by the provided query builder.
+     * @return Map of field names with their weights for multi-field queries.
+     *         For single-field queries, return a map with one entry.
      */
-    protected abstract String getFieldName(QueryBuilder queryBuilder);
+    protected abstract Map<String, Float> getFieldNamesWithWeights(QueryBuilder queryBuilder);
 
     /**
      * @param queryBuilder {@link QueryBuilder}

x-pack/plugin/inference/src/main/java/org/elasticsearch/xpack/inference/queries/SemanticSparseVectorQueryRewriteInterceptor.java

@@ -27,10 +27,10 @@ public class SemanticSparseVectorQueryRewriteInterceptor extends SemanticQueryRe
     public SemanticSparseVectorQueryRewriteInterceptor() {}
 
     @Override
-    protected String getFieldName(QueryBuilder queryBuilder) {
+    protected Map<String, Float> getFieldNamesWithWeights(QueryBuilder queryBuilder) {
         assert (queryBuilder instanceof SparseVectorQueryBuilder);
         SparseVectorQueryBuilder sparseVectorQueryBuilder = (SparseVectorQueryBuilder) queryBuilder;
-        return sparseVectorQueryBuilder.getFieldName();
+        return Map.of(sparseVectorQueryBuilder.getFieldName(), 1.0f);
     }
 
     @Override