List<File> (Object attached) { List<File> result; if (attached instanceof FileFlavorProvider) { result = ((FileFlavorProvider)attached).asFileList(); } else if (attached instanceof DnDNativeTarget.EventInfo) { result = getFileList(((DnDNativeTarget.EventInfo)attached).getTransferable()); } else { result = null; } return result == null ? List.of() : result; }