public Builder mergeRanking(com.google.cloud.vertexai.api.RagRetrievalConfig.Ranking value) {
      if (rankingBuilder_ == null) {
        if (((bitField0_ & 0x00000004) != 0)
            && ranking_ != null
            && ranking_
                != com.google.cloud.vertexai.api.RagRetrievalConfig.Ranking.getDefaultInstance()) {
          getRankingBuilder().mergeFrom(value);
        } else {
          ranking_ = value;
        }
      } else {
        rankingBuilder_.mergeFrom(value);
      }
      if (ranking_ != null) {
        bitField0_ |= 0x00000004;
        onChanged();
      }
      return this;
    }
<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