public Builder setVertexRagStore(com.google.cloud.vertexai.api.VertexRagStore value) {
      if (vertexRagStoreBuilder_ == null) {
        if (value == null) {
          throw new NullPointerException();
        }
        source_ = value;
        onChanged();
      } else {
        vertexRagStoreBuilder_.setMessage(value);
      }
      sourceCase_ = 4;
      return this;
    }
<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