private com.google.protobuf.SingleFieldBuilderV3<
            com.google.cloud.translate.v3beta1.DocumentInputConfig,
            com.google.cloud.translate.v3beta1.DocumentInputConfig.Builder,
            com.google.cloud.translate.v3beta1.DocumentInputConfigOrBuilder>
        getDocumentInputConfigFieldBuilder() {
      if (documentInputConfigBuilder_ == null) {
        documentInputConfigBuilder_ =
            new com.google.protobuf.SingleFieldBuilderV3<
                com.google.cloud.translate.v3beta1.DocumentInputConfig,
                com.google.cloud.translate.v3beta1.DocumentInputConfig.Builder,
                com.google.cloud.translate.v3beta1.DocumentInputConfigOrBuilder>(
                getDocumentInputConfig(), getParentForChildren(), isClean());
        documentInputConfig_ = null;
      }
      return documentInputConfigBuilder_;
    }
<pre>
Required. Input configurations.
</pre>

<code>
.google.cloud.translation.v3beta1.DocumentInputConfig document_input_config = 4 [(.google.api.field_behavior) = REQUIRED];
</code>
java-translate/proto-google-cloud-translate-v3beta1/src/main/java/com/google/cloud/translate/v3beta1/TranslateDocumentRequest.java