class FootprintMerger extends AbstractElementMerger {

    @Override
    public void mergeNodes(List<Node> fromParents, Element toParent, Document toDocument) throws PDUStitchingException {
        final Element posListElement = toDocument.createElement("gml:posList");
        String footprint;
        footprint = createFootprint(fromParents);
        addTextToNode(posListElement, footprint, toDocument);
        toParent.appendChild(posListElement);
    }

      FootprintMerger(File productDir);

}