public Builder mergeDocumentInputConfig(
        com.google.cloud.translate.v3beta1.DocumentInputConfig value) {
      if (documentInputConfigBuilder_ == null) {
        if (((bitField0_ & 0x00000008) != 0)
            && documentInputConfig_ != null
            && documentInputConfig_
                != com.google.cloud.translate.v3beta1.DocumentInputConfig.getDefaultInstance()) {
          getDocumentInputConfigBuilder().mergeFrom(value);
        } else {
          documentInputConfig_ = value;
        }
      } else {
        documentInputConfigBuilder_.mergeFrom(value);
      }
      if (documentInputConfig_ != null) {
        bitField0_ |= 0x00000008;
        onChanged();
      }
      return this;
    }
<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