addressing PR comments - removing duplicated code and opting for switch statement

Author: pmpailis

server/src/main/java/org/elasticsearch/search/vectors/KnnSearchBuilder.java

@@ -10,7 +10,6 @@
 
 import org.apache.lucene.util.SetOnce;
 import org.elasticsearch.TransportVersions;
-import org.elasticsearch.common.ParsingException;
 import org.elasticsearch.common.io.stream.StreamInput;
 import org.elasticsearch.common.io.stream.StreamOutput;
 import org.elasticsearch.common.io.stream.Writeable;
@@ -29,7 +28,6 @@
 import java.io.IOException;
 import java.util.ArrayList;
 import java.util.Arrays;
-import java.util.HexFormat;
 import java.util.List;
 import java.util.Objects;
 import java.util.function.Supplier;
@@ -38,6 +36,7 @@
 import static org.elasticsearch.common.Strings.format;
 import static org.elasticsearch.index.query.AbstractQueryBuilder.DEFAULT_BOOST;
 import static org.elasticsearch.search.SearchService.DEFAULT_SIZE;
+import static org.elasticsearch.search.vectors.KnnVectorQueryBuilder.parseQueryVector;
 import static org.elasticsearch.xcontent.ConstructingObjectParser.constructorArg;
 import static org.elasticsearch.xcontent.ConstructingObjectParser.optionalConstructorArg;
 
@@ -68,52 +67,6 @@ public class KnnSearchBuilder implements Writeable, ToXContentFragment, Rewritea
             .similarity((Float) args[5]);
     });
 
-    private static float[] parseQueryVector(XContentParser parser) throws IOException {
-        XContentParser.Token token = parser.currentToken();
-        final float[] vector;
-        if (token == XContentParser.Token.START_ARRAY) {
-            vector = parseQueryVectorArray(parser);
-        } else if (token == XContentParser.Token.VALUE_STRING) {
-            vector = parseHexEncodedVector(parser);
-        } else if (token == XContentParser.Token.VALUE_NUMBER) {
-            vector = parseNumberVector(parser);
-        } else {
-            throw new ParsingException(parser.getTokenLocation(), format("Unknown type for provided value [%s]", parser.text()));
-        }
-        return vector;
-    }
-
-    private static float[] parseQueryVectorArray(XContentParser parser) throws IOException {
-        XContentParser.Token token;
-        List<Float> vectorArr = new ArrayList<>();
-        while ((token = parser.nextToken()) != XContentParser.Token.END_ARRAY) {
-            if (token == XContentParser.Token.VALUE_NUMBER || token == XContentParser.Token.VALUE_STRING) {
-                vectorArr.add(parser.floatValue());
-            } else {
-                throw new ParsingException(parser.getTokenLocation(), format("Type [%s] not supported for query vector"));
-            }
-        }
-        float[] floatVector = new float[vectorArr.size()];
-        for (int i = 0; i < vectorArr.size(); i++) {
-            floatVector[i] = vectorArr.get(i);
-        }
-        return floatVector;
-    }
-
-    private static float[] parseNumberVector(XContentParser parser) throws IOException {
-        return new float[] { parser.floatValue() };
-    }
-
-    private static float[] parseHexEncodedVector(XContentParser parser) throws IOException {
-        // TODO optimize this as the array returned will be recomputed later again as a byte array
-        byte[] decodedByteQueryVector = HexFormat.of().parseHex(parser.text());
-        float[] floatVector = new float[decodedByteQueryVector.length];
-        for (int i = 0; i < decodedByteQueryVector.length; i++) {
-            floatVector[i] = decodedByteQueryVector[i];
-        }
-        return floatVector;
-    }
-
     static {
         PARSER.declareString(constructorArg(), FIELD_FIELD);
         PARSER.declareField(

server/src/main/java/org/elasticsearch/search/vectors/KnnVectorQueryBuilder.java

@@ -69,19 +69,22 @@ public class KnnVectorQueryBuilder extends AbstractQueryBuilder<KnnVectorQueryBu
         args -> new KnnVectorQueryBuilder((String) args[0], (float[]) args[1], (Integer) args[2], (Float) args[3])
     );
 
-    private static float[] parseQueryVector(XContentParser parser) throws IOException {
+    /**
+     * Utility method to parse the provided {query_vector} parameter. Supports the following formats:
+     * - array of floats, as an n-dimensional vector
+     * - single number, as a 1-dimensional vector
+     * - string, as a hex-encoded byte vector
+     *
+     * @return an array of floats representing the provided query vector
+     */
+    public static float[] parseQueryVector(XContentParser parser) throws IOException {
         XContentParser.Token token = parser.currentToken();
-        final float[] vector;
-        if (token == XContentParser.Token.START_ARRAY) {
-            vector = parseQueryVectorArray(parser);
-        } else if (token == XContentParser.Token.VALUE_STRING) {
-            vector = parseHexEncodedVector(parser);
-        } else if (token == XContentParser.Token.VALUE_NUMBER) {
-            vector = parseNumberVector(parser);
-        } else {
-            throw new ParsingException(parser.getTokenLocation(), format("Unknown type for provided value [%s]", parser.text()));
-        }
-        return vector;
+        return switch (token) {
+            case START_ARRAY -> parseQueryVectorArray(parser);
+            case VALUE_STRING -> parseHexEncodedVector(parser);
+            case VALUE_NUMBER -> parseNumberVector(parser);
+            default -> throw new ParsingException(parser.getTokenLocation(), format("Unknown type for provided value [%s]", parser.text()));
+        };
     }
 
     private static float[] parseQueryVectorArray(XContentParser parser) throws IOException {