docs: private Criteria buildPrefetchCriteriaMultipleKeys(Collection ids, FieldDescriptor fields[])
      {
          Criteria crit = new Criteria();
          Iterator iter = ids.iterator();
          Object[] val;
          Identity id;
  
          while (iter.hasNext())
          {
              Criteria c = new Criteria();
              id = (Identity) iter.next();
              val = id.getPrimaryKeyValues();
              for (int i = 0; i < val.length; i++)
              {
                  if (val[i] == null)
                  {
                      c.addIsNull(fields[i].getAttributeName());
                  }
                  else
                  {
                      c.addEqualTo(fields[i].getAttributeName(), val[i]);
                  }
              }
              crit.addOrCriteria(c);
          }
  
          return crit;
      }