@Override
 public int hashCode() {
   final int prime = 31;
   int result = 1;
   result = prime * result + ((q == null) ? 0 : q.hashCode());
   return result;
 }
 @Override
 public boolean equals(Object obj) {
   if (this == obj) {
     return true;
   }
   if (obj == null) {
     return false;
   }
   if (getClass() != obj.getClass()) {
     return false;
   }
   RelationalNotQuery other = (RelationalNotQuery) obj;
   if (!q.equals(other.q)) {
     return false;
   }
   return true;
 }