@java.lang.Override
  public int getTopK() {
    return topK_;
  }
<pre>
Optional. The number of contexts to retrieve.
</pre>

<code>int32 top_k = 1 [(.google.api.field_behavior) = OPTIONAL];</code>

@return The topK.
java-vertexai/proto-google-cloud-vertexai-v1/src/main/java/com/google/cloud/vertexai/api/RagRetrievalConfig.java