public final OsmLinkHolder getFirstLinkHolder(final OsmNode source) {
        if (n2 != null && n2 != source) {
            return firstlinkholder;
        } else if (n1 != null && n1 != source) {
            return reverselinkholder;
        } else {
            throw new IllegalArgumentException("internal error: getFirstLinkHolder: unknown source");
        }
    }
Reset this link for the given direction
main/src/main/java/cgeo/geocaching/brouter/mapaccess/OsmLink.java