code: public void combine(SearchFilter new_filter, int op) throws DBException
      {
          // If this is not a logical operator, throw an exception
          if ((op & LOGICAL_OPER_MASK) == 0)
          {
              throw new DBException();
              // Create a new vector consisting of just the filters
              // from the SearchFilter classes in new_filters
          }
          Vector filters = new Vector();
          filters.addElement(new_filter.getFilter());
          // Create a node for this list and return it
          m_filter = new SearchBaseNode(op, m_filter, filters);
      }
docs: Combine one other search filters with this one, using the specific operator.
  
  @param new_filter is the SearchFilter class to be combined
  @param op is the logical operator to be used to combine the filters
  @exception DBException