The process of testing for a point can easily be adapted to test our fences against polylines and polygons. In the case of polylines we query the index with the polyline’s bounding box and then test if the polyline actually crosses the returned fences.

polyline_snippet.java

@ApiMethod(name = "polyline", httpMethod = "post", path = "polyline")
    public ArrayList < MyFence > queryPolyLine(@Named("group") String group, MyPolyLine polyline) {
        ArrayList < MyFence > fences = new ArrayList < MyFence > ();

        //Get the index from Memcache.
        MemcacheService syncCache = MemcacheServiceFactory.getMemcacheService();
        GeometryFactory gf = new GeometryFactory();
        STRtree index = (STRtree) syncCache.get(group); // read from cache
        if (index != null) {
            //Create coordinate array.
            double[][] points = polyline.getCoordinates();
            Coordinate[] coordinates = new Coordinate[points.length];
            int i = 0;
            for (double[] point: points) {
                Coordinate coordinate = new Coordinate(point[0], point[1]);
                coordinates[i++] = coordinate;
            }
            //Create polyline.
            GeometryFactory fact = new GeometryFactory();
            LineString linestring = new GeometryFactory().createLineString(coordinates);

            List < MyPolygon > items = index.query(linestring.getEnvelopeInternal());
            if (!items.isEmpty()) {
                for (MyPolygon poly: items) {
                    if (linestring.crosses(poly) || poly.contains(linestring)) {
                        long id = poly.getID();
                        MyFence newFence = new MyFence();
                        newFence.setId(id);
                        fences.add(newFence);
                    }
                }
            }
        } else {
            try {
                MyIndex.buildIndex(group);
            } catch (IOException e) {
                e.printStackTrace();
            }
        }

        return fences;
    }