docs: public boolean doesExist(ClassDescriptor cld, Identity oid, Object obj)
      {
          boolean result = false;
          String sql = (String) sqlSelectMap.get(cld);
          if(sql == null)
          {
              sql = new SqlExistStatement(cld, LoggerFactory.getDefaultLogger()).getStatement();
              sqlSelectMap.put(cld, sql);
          }
          ValueContainer[] pkValues;
          if(oid == null)
          {
              pkValues = getKeyValues(cld, obj, true);
          }
          else
          {
              pkValues = getKeyValues(cld, oid);
          }
          StatementManagerIF sm = m_broker.serviceStatementManager();
          PreparedStatement stmt = null;
          ResultSet rs = null;
          try
          {
              stmt = sm.getPreparedStatement(cld, sql, false, 1, false);
              sm.bindValues(stmt, pkValues, 1);
              rs = stmt.executeQuery();
              result = rs.next();
          }
          catch(SQLException e)
          {
              throw ExceptionHelper.generateException("[BrokerHelper#doesExist] Can't check if specified" +
                      " object is already persisted", e, sql, cld, pkValues, null, obj);
          }
          finally
          {
              sm.closeResources(stmt, rs);
          }
  
          return result;
      }