feature: implement default model id for neural sparse

Signed-off-by: zhichao-aws <[email protected]>

src/main/java/org/opensearch/neuralsearch/query/ModelInferenceQueryBuilder.java

@@ -0,0 +1,27 @@
+/*
+ * Copyright OpenSearch Contributors
+ * SPDX-License-Identifier: Apache-2.0
+ */
+package org.opensearch.neuralsearch.query;
+
+/**
+ * Query builders which calls ml-commons API to do model inference.
+ * The model inference result is used for search on target field.
+ */
+
+public interface ModelInferenceQueryBuilder {
+    /**
+     * Get the model id used by ml-commons model inference. Return null if the model id is absent.
+     */
+    public String modelId();
+
+    /**
+    * Set a new model id for the query builder.
+    */
+    public ModelInferenceQueryBuilder modelId(String modelId);
+
+    /**
+    * Get the field name for search.
+    */
+    public String fieldName();
+}

src/main/java/org/opensearch/neuralsearch/query/NeuralQueryBuilder.java

@@ -58,7 +58,7 @@
 @Accessors(chain = true, fluent = true)
 @NoArgsConstructor
 @AllArgsConstructor
-public class NeuralQueryBuilder extends AbstractQueryBuilder<NeuralQueryBuilder> {
+public class NeuralQueryBuilder extends AbstractQueryBuilder<NeuralQueryBuilder> implements ModelInferenceQueryBuilder {
 
     public static final String NAME = "neural";
 

src/main/java/org/opensearch/neuralsearch/query/NeuralSparseQueryBuilder.java

@@ -55,7 +55,7 @@
 @Accessors(chain = true, fluent = true)
 @NoArgsConstructor
 @AllArgsConstructor
-public class NeuralSparseQueryBuilder extends AbstractQueryBuilder<NeuralSparseQueryBuilder> {
+public class NeuralSparseQueryBuilder extends AbstractQueryBuilder<NeuralSparseQueryBuilder> implements ModelInferenceQueryBuilder {
     public static final String NAME = "neural_sparse";
     @VisibleForTesting
     static final ParseField QUERY_TEXT_FIELD = new ParseField("query_text");

src/main/java/org/opensearch/neuralsearch/query/visitor/NeuralSearchQueryVisitor.java

@@ -9,12 +9,12 @@
 import org.apache.lucene.search.BooleanClause;
 import org.opensearch.index.query.QueryBuilder;
 import org.opensearch.index.query.QueryBuilderVisitor;
-import org.opensearch.neuralsearch.query.NeuralQueryBuilder;
+import org.opensearch.neuralsearch.query.ModelInferenceQueryBuilder;
 
 import lombok.AllArgsConstructor;
 
 /**
- * Neural Search Query Visitor. It visits each and every component of query buikder tree.
+ * Neural Search Query Visitor. It visits each and every component of query builder tree.
  */
 @AllArgsConstructor
 public class NeuralSearchQueryVisitor implements QueryBuilderVisitor {
@@ -28,16 +28,16 @@ public class NeuralSearchQueryVisitor implements QueryBuilderVisitor {
      */
     @Override
     public void accept(QueryBuilder queryBuilder) {
-        if (queryBuilder instanceof NeuralQueryBuilder) {
-            NeuralQueryBuilder neuralQueryBuilder = (NeuralQueryBuilder) queryBuilder;
-            if (neuralQueryBuilder.modelId() == null) {
+        if (queryBuilder instanceof ModelInferenceQueryBuilder) {
+            ModelInferenceQueryBuilder modelInferenceQueryBuilder = (ModelInferenceQueryBuilder) queryBuilder;
+            if (modelInferenceQueryBuilder.modelId() == null) {
                 if (neuralFieldMap != null
-                    && neuralQueryBuilder.fieldName() != null
-                    && neuralFieldMap.get(neuralQueryBuilder.fieldName()) != null) {
-                    String fieldDefaultModelId = (String) neuralFieldMap.get(neuralQueryBuilder.fieldName());
-                    neuralQueryBuilder.modelId(fieldDefaultModelId);
+                    && modelInferenceQueryBuilder.fieldName() != null
+                    && neuralFieldMap.get(modelInferenceQueryBuilder.fieldName()) != null) {
+                    String fieldDefaultModelId = (String) neuralFieldMap.get(modelInferenceQueryBuilder.fieldName());
+                    modelInferenceQueryBuilder.modelId(fieldDefaultModelId);
                 } else if (modelId != null) {
-                    neuralQueryBuilder.modelId(modelId);
+                    modelInferenceQueryBuilder.modelId(modelId);
                 } else {
                     throw new IllegalArgumentException(
                         "model id must be provided in neural query or a default model id must be set in search request processor"