ostream.writeUTF(fileName.substring(collection.getName().length() + 1));
	public byte[] serialize() {		VariableByteOutputStream ostream = new VariableByteOutputStream();		try {			ostream.writeUTF(fileName.substring(collection.getName().length() + 1));			//ostream.writeInt(children);			ostream.writeLong(documentRootId);			((DocumentTypeImpl) docType).write(ostream);		} catch(IOException e) {			LOG.warn("io error while writing document data", e);			return null;		}		return ostream.toByteArray();	}