@java.lang.Override
  public java.lang.String getOutputUriPrefix() {
    java.lang.Object ref = outputUriPrefix_;
    if (ref instanceof java.lang.String) {
      return (java.lang.String) ref;
    } else {
      com.google.protobuf.ByteString bs = (com.google.protobuf.ByteString) ref;
      java.lang.String s = bs.toStringUtf8();
      outputUriPrefix_ = s;
      return s;
    }
  }
<pre>
Required. The bucket used in 'output_uri_prefix' must exist and there must
be no files under 'output_uri_prefix'. 'output_uri_prefix' must end with
"/" and start with "gs://". One 'output_uri_prefix' can only be used by one
batch translation job at a time. Otherwise an INVALID_ARGUMENT (400) error
is returned.
</pre>

<code>string output_uri_prefix = 1 [(.google.api.field_behavior) = REQUIRED];</code>

@return The outputUriPrefix.
java-translate/proto-google-cloud-translate-v3/src/main/java/com/google/cloud/translate/v3/GcsDestination.java