if (!open) throw new IOException(EclipseAdaptorMsg.fileManager_notOpen);
	public File lookup(String target, boolean add) throws IOException {		Entry entry = (Entry) table.get(target);		if (entry == null) {			if (add) {				add(target);				entry = (Entry) table.get(target);			} else {				return null;			}		}		return new File(getAbsolutePath(target + '.' + entry.getReadId()));	}