this.mSortBy = ZMailbox.SearchSortBy.fromString(sortBy);
if (sortBy != null && sortBy.length() > 0) this.mSortBy = ZMailbox.SearchSortBy.fromString(sortBy);
    public void setSort(String sortBy) throws ServiceException {        this.mSortBy = ZMailbox.SearchSortBy.fromString(sortBy);    }