private com.google.protobuf.SingleFieldBuilderV3<
            com.google.cloud.vertexai.api.RagRetrievalConfig.Ranking,
            com.google.cloud.vertexai.api.RagRetrievalConfig.Ranking.Builder,
            com.google.cloud.vertexai.api.RagRetrievalConfig.RankingOrBuilder>
        getRankingFieldBuilder() {
      if (rankingBuilder_ == null) {
        rankingBuilder_ =
            new com.google.protobuf.SingleFieldBuilderV3<
                com.google.cloud.vertexai.api.RagRetrievalConfig.Ranking,
                com.google.cloud.vertexai.api.RagRetrievalConfig.Ranking.Builder,
                com.google.cloud.vertexai.api.RagRetrievalConfig.RankingOrBuilder>(
                getRanking(), getParentForChildren(), isClean());
        ranking_ = null;
      }
      return rankingBuilder_;
    }
<pre>
Optional. Config for ranking and reranking.
</pre>

<code>
.google.cloud.vertexai.v1.RagRetrievalConfig.Ranking ranking = 4 [(.google.api.field_behavior) = OPTIONAL];
</code>
java-vertexai/proto-google-cloud-vertexai-v1/src/main/java/com/google/cloud/vertexai/api/RagRetrievalConfig.java