private com.google.protobuf.SingleFieldBuilderV3<
            com.google.cloud.vertexai.api.VertexRagStore,
            com.google.cloud.vertexai.api.VertexRagStore.Builder,
            com.google.cloud.vertexai.api.VertexRagStoreOrBuilder>
        getVertexRagStoreFieldBuilder() {
      if (vertexRagStoreBuilder_ == null) {
        if (!(sourceCase_ == 4)) {
          source_ = com.google.cloud.vertexai.api.VertexRagStore.getDefaultInstance();
        }
        vertexRagStoreBuilder_ =
            new com.google.protobuf.SingleFieldBuilderV3<
                com.google.cloud.vertexai.api.VertexRagStore,
                com.google.cloud.vertexai.api.VertexRagStore.Builder,
                com.google.cloud.vertexai.api.VertexRagStoreOrBuilder>(
                (com.google.cloud.vertexai.api.VertexRagStore) source_,
                getParentForChildren(),
                isClean());
        source_ = null;
      }
      sourceCase_ = 4;
      onChanged();
      return vertexRagStoreBuilder_;
    }
<pre>
Set to use data source powered by Vertex RAG store.
User data is uploaded via the VertexRagDataService.
</pre>

<code>.google.cloud.vertexai.v1.VertexRagStore vertex_rag_store = 4;</code>
java-vertexai/proto-google-cloud-vertexai-v1/src/main/java/com/google/cloud/vertexai/api/Retrieval.java