public void addRawCallData(LinkCallData copyLinkCallData) {
        Objects.requireNonNull(copyLinkCallData, "copyLinkCallData");

        if (!this.source.equals(copyLinkCallData.source)) {
            throw new IllegalArgumentException("source not equals");
        }
        if (!this.target.equals(copyLinkCallData.target)) {
            throw new IllegalArgumentException("target not equals");
        }

        for (Map.Entry<Long, TimeHistogram> copyEntry : copyLinkCallData.targetHistogramTimeMap.entrySet()) {
            final Long timeStamp = copyEntry.getKey();
            TimeHistogram histogram = getTimeHistogram(timeStamp);
            histogram.add(copyEntry.getValue());
        }
    }
representation of out/in relationship
@author emeroad
web/src/main/java/com/navercorp/pinpoint/web/applicationmap/rawdata/LinkCallData.java