public List<HistogramView> createAgentHistogramViewList() {
        Map<String, List<TimeHistogram>> agentTimeHistogramMap = agentTimeHistogram.getTimeHistogramMap();
        List<HistogramView> result = new ArrayList<>();
        for (Map.Entry<String, Histogram> entry : agentHistogramMap.entrySet()) {
            String agentId = entry.getKey();
            Histogram agentHistogram = entry.getValue();

            List<TimeHistogram> sortedTimeHistogram = agentTimeHistogramMap.computeIfAbsent(agentId, id -> Collections.emptyList());

            HistogramView histogramView = new HistogramView(agentId, agentHistogram, sortedTimeHistogram);
            result.add(histogramView);
        }
        return result;
    }
this class is a collection of
applicationHistogram
agentHistogram
applicationTimeHistogram
agentTimeHistogram

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