Add getNativeClient API to VectorStore interface

Adds getNativeClient API to VectorStore interface allowing access to the underlying native client implementation.

This change:
- Adds getNativeClient() default method to VectorStore interface returning Optional<T>
- Implements getNativeClient() in all vector store implementations exposing their respective native clients
- Adds integration tests verifying native client access for all implementations

Fixes: #2137

Signed-off-by: Soby Chacko <soby.chacko@broadcom.com>

spring-ai-docs/src/main/antora/modules/ROOT/pages/api/vectordbs.adoc

@@ -44,6 +44,10 @@ public interface VectorStore extends DocumentWriter {
     List<Document> similaritySearch(String query);
 
     List<Document> similaritySearch(SearchRequest request);
+
+    default <T> Optional<T> getNativeClient() {
+		return Optional.empty();
+	}
 }
 ```
 

spring-ai-docs/src/main/antora/modules/ROOT/pages/api/vectordbs/apache-cassandra.adoc

@@ -319,3 +319,20 @@ nodetool import wikidata articles ${CASSANDRA_DATA}/data/wikidata/articles-*/
 * An alternative to `nodetool import` is to just restart Cassandra.
 * If there are any failures in the indexes they will be rebuilt automatically.
 ====
+
+== Accessing the Native Client
+
+The Cassandra Vector Store implementation provides access to the underlying native Cassandra client (`CqlSession`) through the `getNativeClient()` method:
+
+[source,java]
+----
+CassandraVectorStore vectorStore = context.getBean(CassandraVectorStore.class);
+Optional<CqlSession> nativeClient = vectorStore.getNativeClient();
+
+if (nativeClient.isPresent()) {
+    CqlSession session = nativeClient.get();
+    // Use the native client for Cassandra-specific operations
+}
+----
+
+The native client gives you access to Cassandra-specific features and operations that might not be exposed through the `VectorStore` interface.

spring-ai-docs/src/main/antora/modules/ROOT/pages/api/vectordbs/azure-cosmos-db.adoc

@@ -205,3 +205,20 @@ Add the following dependency in your Maven project:
     <artifactId>spring-ai-azure-cosmos-db-store</artifactId>
 </dependency>
 ----
+
+== Accessing the Native Client
+
+The Azure Cosmos DB Vector Store implementation provides access to the underlying native Azure Cosmos DB client (`CosmosClient`) through the `getNativeClient()` method:
+
+[source,java]
+----
+CosmosDBVectorStore vectorStore = context.getBean(CosmosDBVectorStore.class);
+Optional<CosmosClient> nativeClient = vectorStore.getNativeClient();
+
+if (nativeClient.isPresent()) {
+    CosmosClient client = nativeClient.get();
+    // Use the native client for Azure Cosmos DB-specific operations
+}
+----
+
+The native client gives you access to Azure Cosmos DB-specific features and operations that might not be exposed through the `VectorStore` interface.

spring-ai-docs/src/main/antora/modules/ROOT/pages/api/vectordbs/azure.adoc

@@ -226,3 +226,20 @@ is converted into the following Azure OData link:https://learn.microsoft.com/en-
 ----
 $filter search.in(meta_country, 'UK,NL', ',') and meta_year ge 2020
 ----
+
+== Accessing the Native Client
+
+The Azure Vector Store implementation provides access to the underlying native Azure Search client (`SearchClient`) through the `getNativeClient()` method:
+
+[source,java]
+----
+AzureVectorStore vectorStore = context.getBean(AzureVectorStore.class);
+Optional<SearchClient> nativeClient = vectorStore.getNativeClient();
+
+if (nativeClient.isPresent()) {
+    SearchClient client = nativeClient.get();
+    // Use the native client for Azure Search-specific operations
+}
+----
+
+The native client gives you access to Azure Search-specific features and operations that might not be exposed through the `VectorStore` interface.

spring-ai-docs/src/main/antora/modules/ROOT/pages/api/vectordbs/coherence.adoc

@@ -0,0 +1,17 @@
+
+== Accessing the Native Client
+
+The Coherence Vector Store implementation provides access to the underlying native Coherence client (`Session`) through the `getNativeClient()` method:
+
+[source,java]
+----
+CoherenceVectorStore vectorStore = context.getBean(CoherenceVectorStore.class);
+Optional<Session> nativeClient = vectorStore.getNativeClient();
+
+if (nativeClient.isPresent()) {
+    Session session = nativeClient.get();
+    // Use the native client for Coherence-specific operations
+}
+----
+
+The native client gives you access to Coherence-specific features and operations that might not be exposed through the `VectorStore` interface.

spring-ai-docs/src/main/antora/modules/ROOT/pages/api/vectordbs/elasticsearch.adoc

@@ -269,3 +269,20 @@ public EmbeddingModel embeddingModel() {
     return new OpenAiEmbeddingModel(new OpenAiApi(System.getenv("OPENAI_API_KEY")));
 }
 ----
+
+== Accessing the Native Client
+
+The Elasticsearch Vector Store implementation provides access to the underlying native Elasticsearch client (`ElasticsearchClient`) through the `getNativeClient()` method:
+
+[source,java]
+----
+ElasticsearchVectorStore vectorStore = context.getBean(ElasticsearchVectorStore.class);
+Optional<ElasticsearchClient> nativeClient = vectorStore.getNativeClient();
+
+if (nativeClient.isPresent()) {
+    ElasticsearchClient client = nativeClient.get();
+    // Use the native client for Elasticsearch-specific operations
+}
+----
+
+The native client gives you access to Elasticsearch-specific features and operations that might not be exposed through the `VectorStore` interface.

spring-ai-docs/src/main/antora/modules/ROOT/pages/api/vectordbs/mariadb.adoc

@@ -204,3 +204,20 @@ vectorStore.similaritySearch(SearchRequest.builder()
 ----
 
 NOTE: These filter expressions are automatically converted into the equivalent MariaDB JSON path expressions.
+
+== Accessing the Native Client
+
+The MariaDB Vector Store implementation provides access to the underlying native JDBC client (`JdbcTemplate`) through the `getNativeClient()` method:
+
+[source,java]
+----
+MariaDBVectorStore vectorStore = context.getBean(MariaDBVectorStore.class);
+Optional<JdbcTemplate> nativeClient = vectorStore.getNativeClient();
+
+if (nativeClient.isPresent()) {
+    JdbcTemplate jdbc = nativeClient.get();
+    // Use the native client for MariaDB-specific operations
+}
+----
+
+The native client gives you access to MariaDB-specific features and operations that might not be exposed through the `VectorStore` interface.

spring-ai-docs/src/main/antora/modules/ROOT/pages/api/vectordbs/milvus.adoc

@@ -229,3 +229,20 @@ If Docker complains about resources, then execute:
 ----
 docker system prune --all --force --volumes
 ----
+
+== Accessing the Native Client
+
+The Milvus Vector Store implementation provides access to the underlying native Milvus client (`MilvusServiceClient`) through the `getNativeClient()` method:
+
+[source,java]
+----
+MilvusVectorStore vectorStore = context.getBean(MilvusVectorStore.class);
+Optional<MilvusServiceClient> nativeClient = vectorStore.getNativeClient();
+
+if (nativeClient.isPresent()) {
+    MilvusServiceClient client = nativeClient.get();
+    // Use the native client for Milvus-specific operations
+}
+----
+
+The native client gives you access to Milvus-specific features and operations that might not be exposed through the `VectorStore` interface.

spring-ai-docs/src/main/antora/modules/ROOT/pages/api/vectordbs/mongodb.adoc

@@ -228,3 +228,20 @@ To get started with Spring AI and MongoDB:
 
 * See the https://www.mongodb.com/docs/atlas/atlas-vector-search/ai-integrations/spring-ai/#std-label-spring-ai[Getting Started guide for Spring AI Integration].
 * For a comprehensive code example demonstrating Retrieval Augmented Generation (RAG) with Spring AI and MongoDB, refer to this https://www.mongodb.com/developer/languages/java/retrieval-augmented-generation-spring-ai/[detailed tutorial].
+
+== Accessing the Native Client
+
+The MongoDB Atlas Vector Store implementation provides access to the underlying native MongoDB client (`MongoClient`) through the `getNativeClient()` method:
+
+[source,java]
+----
+MongoDBAtlasVectorStore vectorStore = context.getBean(MongoDBAtlasVectorStore.class);
+Optional<MongoClient> nativeClient = vectorStore.getNativeClient();
+
+if (nativeClient.isPresent()) {
+    MongoClient client = nativeClient.get();
+    // Use the native client for MongoDB-specific operations
+}
+----
+
+The native client gives you access to MongoDB-specific features and operations that might not be exposed through the `VectorStore` interface.

spring-ai-docs/src/main/antora/modules/ROOT/pages/api/vectordbs/neo4j.adoc

@@ -237,3 +237,20 @@ is converted into the proprietary Neo4j filter format:
 ----
 node.`metadata.author` IN ["john","jill"] AND node.`metadata.'article_type'` = "blog"
 ----
+
+== Accessing the Native Client
+
+The Neo4j Vector Store implementation provides access to the underlying native Neo4j client (`Driver`) through the `getNativeClient()` method:
+
+[source,java]
+----
+Neo4jVectorStore vectorStore = context.getBean(Neo4jVectorStore.class);
+Optional<Driver> nativeClient = vectorStore.getNativeClient();
+
+if (nativeClient.isPresent()) {
+    Driver driver = nativeClient.get();
+    // Use the native client for Neo4j-specific operations
+}
+----
+
+The native client gives you access to Neo4j-specific features and operations that might not be exposed through the `VectorStore` interface.

spring-ai-docs/src/main/antora/modules/ROOT/pages/api/vectordbs/opensearch.adoc

@@ -238,3 +238,20 @@ is converted into the proprietary OpenSearch filter format:
 ----
 (metadata.author:john OR jill) AND metadata.article_type:blog
 ----
+
+== Accessing the Native Client
+
+The OpenSearch Vector Store implementation provides access to the underlying native OpenSearch client (`OpenSearchClient`) through the `getNativeClient()` method:
+
+[source,java]
+----
+OpenSearchVectorStore vectorStore = context.getBean(OpenSearchVectorStore.class);
+Optional<OpenSearchClient> nativeClient = vectorStore.getNativeClient();
+
+if (nativeClient.isPresent()) {
+    OpenSearchClient client = nativeClient.get();
+    // Use the native client for OpenSearch-specific operations
+}
+----
+
+The native client gives you access to OpenSearch-specific features and operations that might not be exposed through the `VectorStore` interface.

spring-ai-docs/src/main/antora/modules/ROOT/pages/api/vectordbs/oracle.adoc

@@ -206,3 +206,20 @@ You can then connect to the database using:
 ----
 sql mlops/mlops@localhost/freepdb1
 ----
+
+== Accessing the Native Client
+
+The Oracle Vector Store implementation provides access to the underlying native Oracle client (`OracleConnection`) through the `getNativeClient()` method:
+
+[source,java]
+----
+OracleVectorStore vectorStore = context.getBean(OracleVectorStore.class);
+Optional<OracleConnection> nativeClient = vectorStore.getNativeClient();
+
+if (nativeClient.isPresent()) {
+    OracleConnection connection = nativeClient.get();
+    // Use the native client for Oracle-specific operations
+}
+----
+
+The native client gives you access to Oracle-specific features and operations that might not be exposed through the `VectorStore` interface.

spring-ai-docs/src/main/antora/modules/ROOT/pages/api/vectordbs/pgvector.adoc

@@ -243,3 +243,20 @@ You can connect to this server like this:
 ----
 psql -U postgres -h localhost -p 5432
 ----
+
+== Accessing the Native Client
+
+The PGVector Store implementation provides access to the underlying native JDBC client (`JdbcTemplate`) through the `getNativeClient()` method:
+
+[source,java]
+----
+PgVectorStore vectorStore = context.getBean(PgVectorStore.class);
+Optional<JdbcTemplate> nativeClient = vectorStore.getNativeClient();
+
+if (nativeClient.isPresent()) {
+    JdbcTemplate jdbc = nativeClient.get();
+    // Use the native client for PostgreSQL-specific operations
+}
+----
+
+The native client gives you access to PostgreSQL-specific features and operations that might not be exposed through the `VectorStore` interface.

spring-ai-docs/src/main/antora/modules/ROOT/pages/api/vectordbs/pinecone.adoc

@@ -222,3 +222,20 @@ List<Document> results = vectorStore.similaritySearch(SearchRequest.query("Sprin
 ----
 
 If all goes well, you should retrieve the document containing the text "Spring AI rocks!!".
+
+== Accessing the Native Client
+
+The Pinecone Vector Store implementation provides access to the underlying native Pinecone client (`PineconeConnection`) through the `getNativeClient()` method:
+
+[source,java]
+----
+PineconeVectorStore vectorStore = context.getBean(PineconeVectorStore.class);
+Optional<PineconeConnection> nativeClient = vectorStore.getNativeClient();
+
+if (nativeClient.isPresent()) {
+    PineconeConnection client = nativeClient.get();
+    // Use the native client for Pinecone-specific operations
+}
+----
+
+The native client gives you access to Pinecone-specific features and operations that might not be exposed through the `VectorStore` interface.

spring-ai-docs/src/main/antora/modules/ROOT/pages/api/vectordbs/qdrant.adoc

@@ -194,3 +194,20 @@ vectorStore.similaritySearch(SearchRequest.builder()
 ----
 
 NOTE: These (portable) filter expressions get automatically converted into the proprietary Qdrant link:https://qdrant.tech/documentation/concepts/filtering/[filter expressions].
+
+== Accessing the Native Client
+
+The Qdrant Vector Store implementation provides access to the underlying native Qdrant client (`QdrantClient`) through the `getNativeClient()` method:
+
+[source,java]
+----
+QdrantVectorStore vectorStore = context.getBean(QdrantVectorStore.class);
+Optional<QdrantClient> nativeClient = vectorStore.getNativeClient();
+
+if (nativeClient.isPresent()) {
+    QdrantClient client = nativeClient.get();
+    // Use the native client for Qdrant-specific operations
+}
+----
+
+The native client gives you access to Qdrant-specific features and operations that might not be exposed through the `VectorStore` interface.

spring-ai-docs/src/main/antora/modules/ROOT/pages/api/vectordbs/redis.adoc

@@ -212,3 +212,20 @@ public EmbeddingModel embeddingModel() {
 You must list explicitly all metadata field names and types (`TAG`, `TEXT`, or `NUMERIC`) for any metadata field used in filter expressions.
 The `metadataFields` above registers filterable metadata fields: `country` of type `TAG`, `year` of type `NUMERIC`.
 ====
+
+== Accessing the Native Client
+
+The Redis Vector Store implementation provides access to the underlying native Redis client (`JedisPooled`) through the `getNativeClient()` method:
+
+[source,java]
+----
+RedisVectorStore vectorStore = context.getBean(RedisVectorStore.class);
+Optional<JedisPooled> nativeClient = vectorStore.getNativeClient();
+
+if (nativeClient.isPresent()) {
+    JedisPooled jedis = nativeClient.get();
+    // Use the native client for Redis-specific operations
+}
+----
+
+The native client gives you access to Redis-specific features and operations that might not be exposed through the `VectorStore` interface.

spring-ai-docs/src/main/antora/modules/ROOT/pages/api/vectordbs/typesense.adoc

@@ -229,3 +229,20 @@ If you are not retrieving the documents in the expected order or the search resu
 
 Embedding models can have a significant impact on the search results (i.e. make sure if your data is in Spanish to use a Spanish or multilingual embedding model).
 ====
+
+== Accessing the Native Client
+
+The Typesense Vector Store implementation provides access to the underlying native Typesense client (`Client`) through the `getNativeClient()` method:
+
+[source,java]
+----
+TypesenseVectorStore vectorStore = context.getBean(TypesenseVectorStore.class);
+Optional<Client> nativeClient = vectorStore.getNativeClient();
+
+if (nativeClient.isPresent()) {
+    Client client = nativeClient.get();
+    // Use the native client for Typesense-specific operations
+}
+----
+
+The native client gives you access to Typesense-specific features and operations that might not be exposed through the `VectorStore` interface.

spring-ai-docs/src/main/antora/modules/ROOT/pages/api/vectordbs/weaviate.adoc

@@ -230,3 +230,20 @@ You can use the following properties in your Spring Boot configuration to custom
 |`spring.ai.vectorstore.weaviate.consistency-level`|Desired tradeoff between consistency and speed|ConsistentLevel.ONE
 |`spring.ai.vectorstore.weaviate.filter-field`|Configures metadata fields that can be used in filters. Format: spring.ai.vectorstore.weaviate.filter-field.<field-name>=<field-type>|
 |===
+
+== Accessing the Native Client
+
+The Weaviate Vector Store implementation provides access to the underlying native Weaviate client (`WeaviateClient`) through the `getNativeClient()` method:
+
+[source,java]
+----
+WeaviateVectorStore vectorStore = context.getBean(WeaviateVectorStore.class);
+Optional<WeaviateClient> nativeClient = vectorStore.getNativeClient();
+
+if (nativeClient.isPresent()) {
+    WeaviateClient client = nativeClient.get();
+    // Use the native client for Weaviate-specific operations
+}
+----
+
+The native client gives you access to Weaviate-specific features and operations that might not be exposed through the `VectorStore` interface.