/** * statistic sth. * * <p>implement by subclass. * * @return statistic data */ protected String statistic() { CPUUsage current = currentCPUUsage(); double usagePercent = current.usagePercent(_last); double idlePercent = current.idlePercent(_last); _last = current; return String.format("%4.2f, %4.2f", usagePercent, idlePercent); }