public Builder clearVertexAiSearch() {
      if (vertexAiSearchBuilder_ == null) {
        if (sourceCase_ == 2) {
          sourceCase_ = 0;
          source_ = null;
          onChanged();
        }
      } else {
        if (sourceCase_ == 2) {
          sourceCase_ = 0;
          source_ = null;
        }
        vertexAiSearchBuilder_.clear();
      }
      return this;
    }
<pre>
Set to use data source powered by Vertex AI Search.
</pre>

<code>.google.cloud.vertexai.v1.VertexAISearch vertex_ai_search = 2;</code>
java-vertexai/proto-google-cloud-vertexai-v1/src/main/java/com/google/cloud/vertexai/api/Retrieval.java