Enable support for default model id on HybridQueryBuilder

CHANGELOG.md

@@ -22,6 +22,7 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
 ### Bug Fixes
 - Fixing multiple issues reported in #497 ([#524](https://github.com/opensearch-project/neural-search/pull/524))
 - Fix Flaky test reported in #433 ([#533](https://github.com/opensearch-project/neural-search/pull/533))
+- Enable support for default model id on HybridQueryBuilder ([#541](https://github.com/opensearch-project/neural-search/pull/541))
 ### Infrastructure
 - BWC tests for Neural Search ([#515](https://github.com/opensearch-project/neural-search/pull/515))
 - Github action to run integ tests in secure opensearch cluster ([#535](https://github.com/opensearch-project/neural-search/pull/535))

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

@@ -13,6 +13,7 @@
 import java.util.stream.Collectors;
 
 import org.apache.commons.lang.builder.EqualsBuilder;
+import org.apache.lucene.search.BooleanClause.Occur;
 import org.apache.lucene.search.Query;
 import org.opensearch.common.lucene.search.Queries;
 import org.opensearch.core.ParseField;
@@ -27,6 +28,7 @@
 import org.opensearch.index.query.QueryShardContext;
 import org.opensearch.index.query.QueryShardException;
 import org.opensearch.index.query.Rewriteable;
+import org.opensearch.index.query.QueryBuilderVisitor;
 
 import lombok.Getter;
 import lombok.NoArgsConstructor;
@@ -295,4 +297,18 @@ private Collection<Query> toQueries(Collection<QueryBuilder> queryBuilders, Quer
         }).filter(Objects::nonNull).collect(Collectors.toList());
         return queries;
     }
+
+    /**
+     * visit method to parse the HybridQueryBuilder by a visitor
+     */
+    @Override
+    public void visit(QueryBuilderVisitor visitor) {
+        visitor.accept(this);
+        // getChildVisitor of NeuralSearchQueryVisitor return this.
+        // therefore any argument can be passed. Here we have used Occcur.MUST as an argument.
+        QueryBuilderVisitor subVisitor = visitor.getChildVisitor(Occur.MUST);
+        for (QueryBuilder subQueryBuilder : queries) {
+            subQueryBuilder.visit(subVisitor);
+        }
+    }
 }

src/test/java/org/opensearch/neuralsearch/processor/NeuralQueryEnricherProcessorIT.java

@@ -15,6 +15,7 @@
 import org.junit.Before;
 import org.opensearch.common.settings.Settings;
 import org.opensearch.neuralsearch.BaseNeuralSearchIT;
+import org.opensearch.neuralsearch.query.HybridQueryBuilder;
 import org.opensearch.neuralsearch.query.NeuralQueryBuilder;
 
 import com.google.common.primitives.Floats;
@@ -62,6 +63,25 @@ public void testNeuralQueryEnricherProcessor_whenNoModelIdPassed_thenSuccess() {
 
     }
 
+    @SneakyThrows
+    public void testNeuralQueryEnricherProcessor_whenHybridQueryBuilderAndNoModelIdPassed_thenSuccess() {
+        initializeIndexIfNotExist();
+        String modelId = getDeployedModelId();
+        createSearchRequestProcessor(modelId, search_pipeline);
+        createPipelineProcessor(modelId, ingest_pipeline);
+        updateIndexSettings(index, Settings.builder().put("index.search.default_pipeline", search_pipeline));
+        NeuralQueryBuilder neuralQueryBuilder = new NeuralQueryBuilder();
+        neuralQueryBuilder.fieldName(TEST_KNN_VECTOR_FIELD_NAME_1);
+        neuralQueryBuilder.queryText("Hello World");
+        neuralQueryBuilder.k(1);
+        HybridQueryBuilder hybridQueryBuilder = new HybridQueryBuilder();
+        hybridQueryBuilder.add(neuralQueryBuilder);
+        Map<String, Object> response = search(index, hybridQueryBuilder, 2);
+
+        assertFalse(response.isEmpty());
+
+    }
+
     @SneakyThrows
     private void initializeIndexIfNotExist() {
         if (index.equals(NeuralQueryEnricherProcessorIT.index) && !indexExists(index)) {

src/test/java/org/opensearch/neuralsearch/query/HybridQueryBuilderTests.java

@@ -20,6 +20,7 @@
 import java.util.Iterator;
 import java.util.List;
 import java.util.Map;
+import java.util.ArrayList;
 import java.util.function.Supplier;
 
 import org.apache.lucene.search.MatchNoDocsQuery;
@@ -708,6 +709,13 @@ public void testBoost_whenDefaultBoostSet_thenBuildSuccessfully() {
         assertNotNull(hybridQueryBuilder);
     }
 
+    public void testVisit() {
+        HybridQueryBuilder hybridQueryBuilder = new HybridQueryBuilder().add(new NeuralQueryBuilder()).add(new NeuralSparseQueryBuilder());
+        List<QueryBuilder> visitedQueries = new ArrayList<>();
+        hybridQueryBuilder.visit(createTestVisitor(visitedQueries));
+        assertEquals(3, visitedQueries.size());
+    }
+
     private Map<String, Object> getInnerMap(Object innerObject, String queryName, String fieldName) {
         if (!(innerObject instanceof Map)) {
             fail("field name does not map to nested object");

src/test/java/org/opensearch/neuralsearch/query/OpenSearchQueryTestCase.java

@@ -7,6 +7,14 @@
 import static java.util.Collections.emptyMap;
 import static java.util.Collections.singletonMap;
 import static java.util.stream.Collectors.toList;
+import org.apache.lucene.search.DocIdSetIterator;
+import org.apache.lucene.search.Explanation;
+import org.apache.lucene.search.Query;
+import org.apache.lucene.search.Scorer;
+import org.apache.lucene.search.Weight;
+import org.apache.lucene.search.BooleanClause;
+import org.opensearch.index.query.QueryBuilder;
+import org.opensearch.index.query.QueryBuilderVisitor;
 import static org.opensearch.neuralsearch.settings.NeuralSearchSettings.NEURAL_SEARCH_HYBRID_SEARCH_DISABLED;
 
 import java.io.IOException;
@@ -20,11 +28,6 @@
 import org.apache.lucene.document.FieldType;
 import org.apache.lucene.document.TextField;
 import org.apache.lucene.index.LeafReaderContext;
-import org.apache.lucene.search.DocIdSetIterator;
-import org.apache.lucene.search.Explanation;
-import org.apache.lucene.search.Query;
-import org.apache.lucene.search.Scorer;
-import org.apache.lucene.search.Weight;
 import org.opensearch.Version;
 import org.opensearch.cluster.metadata.IndexMetadata;
 import org.opensearch.common.CheckedConsumer;
@@ -230,4 +233,18 @@ public float getMaxScore(int upTo) {
     protected static void initFeatureFlags() {
         System.setProperty(NEURAL_SEARCH_HYBRID_SEARCH_DISABLED.getKey(), "true");
     }
+
+    protected static QueryBuilderVisitor createTestVisitor(List<QueryBuilder> visitedQueries) {
+        return new QueryBuilderVisitor() {
+            @Override
+            public void accept(QueryBuilder qb) {
+                visitedQueries.add(qb);
+            }
+
+            @Override
+            public QueryBuilderVisitor getChildVisitor(BooleanClause.Occur occur) {
+                return this;
+            }
+        };
+    }
 }