private Histogram createApplicationLevelResponseTime(List<ResponseTime> responseHistogram) {
            final Histogram applicationHistogram = new Histogram(this.application.getServiceType());
            for (ResponseTime responseTime : responseHistogram) {
                final Collection<TimeHistogram> histogramList = responseTime.getAgentResponseHistogramList();
                applicationHistogram.addAll(histogramList);
            }
            return applicationHistogram;
        }
this class is a collection of
applicationHistogram
agentHistogram
applicationTimeHistogram
agentTimeHistogram

@author emeroad
web/src/main/java/com/navercorp/pinpoint/web/applicationmap/histogram/NodeHistogram.java