@Override
 public <T extends GettableById> List<T> get(
     Class<T> bookEntityClass,
     int from,
     int to,
     Map<String, List<Criterion>> restrictions,
     OrderByFilter filter) {
   validateTransaction();
   Criteria criteria = getSession().createCriteria(bookEntityClass);
   criteria.setResultTransformer(Criteria.DISTINCT_ROOT_ENTITY);
   criteria.setFirstResult(from);
   if (to != 0) criteria.setMaxResults(to);
   for (String key : restrictions.keySet()) {
     if (key.equals(RestrictionsFields.MAIN_RESTRICTIONS)) {
       for (Criterion restriction : restrictions.get(RestrictionsFields.MAIN_RESTRICTIONS))
         criteria.add(restriction);
     } else if (restrictions.get(key).size() > 0) {
       Criteria c = criteria.createCriteria(key);
       for (Criterion restriction : restrictions.get(key)) c.add(restriction);
     }
   }
   if (filter != null) {
     if (filter.getDirection().equals(OrderByFilter.ASC))
       criteria.addOrder(Order.asc(filter.field));
     else criteria.addOrder(Order.desc(filter.field));
   }
   return criteria.list();
 }
 @Override
 public <T extends GettableById> List<T> get(
     Class<T> bookEntityClass, int from, int to, OrderByFilter filter) {
   validateTransaction();
   Criteria criteria = getSession().createCriteria(bookEntityClass);
   criteria.setResultTransformer(Criteria.DISTINCT_ROOT_ENTITY);
   criteria.setFirstResult(from);
   if (to != 0) criteria.setMaxResults(to);
   if (filter != null) {
     if (filter.getDirection().equals(OrderByFilter.ASC))
       criteria.addOrder(Order.asc(filter.field));
     else criteria.addOrder(Order.desc(filter.field));
   }
   return criteria.list();
 }