boolean isFile(URI id) throws IOException {
final String entry = id.toASCIIString();
final List<String> entries = new ArrayList<String>();
DataStore store = runtime.getDataStore();
store.infoEntry(entry, entry, "*/*", new DataInfo() {
public void list(URI id, String media, long lastModified)
throws IOException {
if (media != null) {
entries.add(media);
}