public Builder mergeRagRetrievalConfig(com.google.cloud.vertexai.api.RagRetrievalConfig value) {
      if (ragRetrievalConfigBuilder_ == null) {
        if (((bitField0_ & 0x00000008) != 0)
            && ragRetrievalConfig_ != null
            && ragRetrievalConfig_
                != com.google.cloud.vertexai.api.RagRetrievalConfig.getDefaultInstance()) {
          getRagRetrievalConfigBuilder().mergeFrom(value);
        } else {
          ragRetrievalConfig_ = value;
        }
      } else {
        ragRetrievalConfigBuilder_.mergeFrom(value);
      }
      if (ragRetrievalConfig_ != null) {
        bitField0_ |= 0x00000008;
        onChanged();
      }
      return this;
    }
<pre>
Optional. The retrieval config for the Rag query.
</pre>

<code>
.google.cloud.vertexai.v1.RagRetrievalConfig rag_retrieval_config = 6 [(.google.api.field_behavior) = OPTIONAL];
</code>
java-vertexai/proto-google-cloud-vertexai-v1/src/main/java/com/google/cloud/vertexai/api/VertexRagStore.java