public Atom10FeedFormatter GetCollectionFragmentsFeed(string collectionId, string since, string before, string page)
        {
            try {
                var sinceDt = DateTime.MinValue;
                if (since != null)
                {
                    DateTime.TryParse(since, out sinceDt);
                }

                var beforeDt = DateTime.MinValue;
                if (before != null)
                {
                    DateTime.TryParse(before, out beforeDt);
                }

                var pageInt = 1;
                if (!String.IsNullOrEmpty(page))
                {
                    pageInt = int.Parse(page);
                }

                var feed = _serverCore.GetFragmentsFeed(collectionId, sinceDt, beforeDt, pageInt);
                if (feed == null)
                {
                    RaiseNotFound("No collection with id " + collectionId);
                }
                return(feed);
            }
            catch (Exception ex)
            {
                if (!(ex is WebFaultException <string>))
                {
                    RaiseServerException(ex,
                                         "Error processing GetCollectionFragmentsFeed for " + collectionId +
                                         " see server logs for details.");
                    return(null);
                }
                throw;
            }
        }