class LastModifiedHelper {

	static long getLastModified(Source source) {
		if (source instanceof DOMSource) {
			Document document = TraxUtils.getDocument((DOMSource) source);
			return document != null ? getLastModified(document.getDocumentURI()) : -1;
		} else {
			return getLastModified(source.getSystemId());
		}
	}

	private  LastModifiedHelper();

}