private Seq<PolygonwithHoles> buildMultipolygons(
Hashtable<Long, Point2D> nodes,
Hashtable<Long, List<Long>> multipolygonWays,
List<List<Tuple2<WayRole, Long>>> multipolygonWayRefs) {
return Seq.seq(multipolygonWayRefs)
.map(
waysOfPoly -> {
try {
// I know this not how should assemble them, but parsing OSM wasn't our objective.
List<Polygon> holes = new ArrayList<>();
Polygon outer = null;
for (Tuple2<WayRole, Long> way : waysOfPoly) {
WayRole role = way.v1;
long wayRef = way.v2;
List<Long> nodeRefs = multipolygonWays.get(wayRef);
Polygon p = buildPolygonFromWayRefs(nodeRefs, nodes);
if (role == WayRole.OUTER && outer == null && p.GetPointsNumber() > 0) {
outer = p;
} else if (role == WayRole.INNER && p.GetPointsNumber() > 0) {
holes.add(p);
} else {
LOG.warn("Could not process a way");
}
}
return new PolygonwithHoles(outer, holes);
} catch (Exception ex) {
// System.out.println("Failed to build a certain multipolygon");
}
return null;
})
.filter(p -> p != null);
}
/**
* Requires vn to point to a way element. From there it iterates over all matches of the ap. Puts
* a dummy point into nodes for every node it finds.
*/
private List<Long> extractNodeRefs(VTDNav vn, Hashtable<Long, Point2D> nodes)
throws NavException, XPathEvalException {
vn.push();
List<Long> refs = new ArrayList<>();
for (int j = NODE_REF_PATH.evalXPath(); j != -1; j = NODE_REF_PATH.evalXPath()) {
long ref = Long.parseLong(vn.toString(j + 1));
refs.add(ref);
nodes.put(ref, new Point2D(0, 0));
}
NODE_REF_PATH.resetXPath();
vn.pop();
return refs;
}