@java.lang.Override
  public com.google.cloud.translate.v3.GcsSource getGcsSource() {
    if (sourceCase_ == 2) {
      return (com.google.cloud.translate.v3.GcsSource) source_;
    }
    return com.google.cloud.translate.v3.GcsSource.getDefaultInstance();
  }
<pre>
Google Cloud Storage location. This must be a single file.
For example: gs://example_bucket/example_file.pdf
</pre>

<code>.google.cloud.translation.v3.GcsSource gcs_source = 2;</code>

@return The gcsSource.
java-translate/proto-google-cloud-translate-v3/src/main/java/com/google/cloud/translate/v3/DocumentInputConfig.java