@java.lang.Override
      public com.google.cloud.vertexai.api.RagRetrievalConfig.Ranking.RankServiceOrBuilder
          getRankServiceOrBuilder() {
        if ((rankingConfigCase_ == 1) && (rankServiceBuilder_ != null)) {
          return rankServiceBuilder_.getMessageOrBuilder();
        } else {
          if (rankingConfigCase_ == 1) {
            return (com.google.cloud.vertexai.api.RagRetrievalConfig.Ranking.RankService)
                rankingConfig_;
          }
          return com.google.cloud.vertexai.api.RagRetrievalConfig.Ranking.RankService
              .getDefaultInstance();
        }
      }
<pre>
Optional. Config for Rank Service.
</pre>

<code>
.google.cloud.vertexai.v1.RagRetrievalConfig.Ranking.RankService rank_service = 1 [(.google.api.field_behavior) = OPTIONAL];
</code>
java-vertexai/proto-google-cloud-vertexai-v1/src/main/java/com/google/cloud/vertexai/api/RagRetrievalConfig.java