code: protected long buildNextSequence(PersistenceBroker broker, ClassDescriptor cld, String sequenceName)
              throws LookupException, SQLException, PlatformException
      {
          CallableStatement cs = null;
          try
          {
              Connection con = broker.serviceConnectionManager().getConnection();
              cs = getPlatform().prepareNextValProcedureStatement(con, PROCEDURE_NAME, sequenceName);
              cs.executeUpdate();
              return cs.getLong(1);
          }
          finally
          {
              try
              {
                  if (cs != null)
                      cs.close();
              }
              catch (SQLException ignore)
              {
                  // ignore it
              }
          }
      }
docs: Calls the stored procedure stored procedure throws an
  error if it doesn't exist.
  @param broker
  @param cld
  @param sequenceName
  @return
  @throws LookupException
  @throws SQLException