public void add(final Histogram histogram) {
        Objects.requireNonNull(histogram, "histogram");

        if (this.schema != histogram.schema) {
            throw new IllegalArgumentException("schema not equals. this=" + this + ", histogram=" + histogram);

        }
        this.fastCount += histogram.getFastCount();
        this.fastErrorCount += histogram.getFastErrorCount();
        this.normalCount += histogram.getNormalCount();
        this.normalErrorCount += histogram.getNormalErrorCount();
        this.slowCount += histogram.getSlowCount();
        this.slowErrorCount += histogram.getSlowErrorCount();
        this.verySlowCount += histogram.getVerySlowCount();
        this.verySlowErrorCount += histogram.getVerySlowErrorCount();
        this.sumElapsed += histogram.getSumElapsed();
        updateMaxElapsed(histogram.getMaxElapsed());
        this.pingCount += histogram.getPingCount();
    }
@author emeroad
@author netspider
@author jaehong.kim
web/src/main/java/com/navercorp/pinpoint/web/applicationmap/histogram/Histogram.java