cdmlib-persistence/src/main/java/eu/etaxonomy/cdm/persistence/query/RandomOrder.java

   1 package eu.etaxonomy.cdm.persistence.query;
   2
   3 import java.util.Map;
   4
   5 import org.hibernate.Criteria;
   6 import org.hibernate.HibernateException;
   7 import org.hibernate.criterion.CriteriaQuery;
   8 import org.hibernate.criterion.Order;
   9 import org.hibernate.envers.query.AuditQuery;
  10 import org.hibernate.internal.util.StringHelper;
  11
  12 import eu.etaxonomy.cdm.persistence.dao.common.OperationNotSupportedInPriorViewException;
  13
  14
  15 public class RandomOrder extends OrderHint {
  16
  17     private static final long serialVersionUID = 9013839425292632385L;
  18     private final static String PROPERTY_NAME = "uselessAnyways";
  19
  20         public RandomOrder() {
  21                 super(RandomOrder.PROPERTY_NAME,SortOrder.ASCENDING);
  22     }
  23
  24         @Override
  25         public void add(Criteria criteria, Map<String, Criteria> criteriaMap) {
  26                 criteria.addOrder(new RandomHibernateOrder());
  27         }
  28
  29         public class RandomHibernateOrder extends Order {
  30                 private static final long serialVersionUID = 8231534219451938847L;
  31
  32
  33                 protected RandomHibernateOrder() {
  34                         super(RandomOrder.PROPERTY_NAME, true);
  35                 }
  36
  37
  38                 @Override
  39                 public String toSqlString(Criteria criteria, CriteriaQuery criteriaQuery)
  40                 throws HibernateException {
  41                 StringBuilder fragment = new StringBuilder();
  42                 fragment.append(" rand()");
  43                 return StringHelper.replace(fragment.toString(), "{alias}",
  44                 criteriaQuery.getSQLAlias(criteria));
  45                 }
  46         }
  47
  48         @Override
  49         public void add(AuditQuery query) {
  50                         throw new OperationNotSupportedInPriorViewException("You cannot sort in a random order in the history view");
  51         }
  52 }