return next.convert(entity);
} else {
String json = DatastoreUtil.getExistingProperty(entity, DATA_PROPERTY, Text.class).getValue();
try {
JSONObject obj = new JSONObject(json);
DeltaGsonImpl delta = new DeltaGsonImpl();
delta.setAuthor(obj.getJSONObject("author").getString("email"));
delta.setTimestampMillis(obj.getLong("time"));
delta.setOperation(SERIALIZER.deserializeOp(obj.getJSONObject("op").toString()));
return new ChangeData<String>(new ClientId(obj.getString("sid")),
GsonProto.toJson(delta));
} catch (MessageException e) {
throw new RuntimeException("MessageException converting " + entity, e);
} catch (JSONException e) {