Polygon.java

/**
 * Copyright (c) Codice Foundation
 * <p/>
 * This is free software: you can redistribute it and/or modify it under the terms of the GNU Lesser
 * General Public License as published by the Free Software Foundation, either version 3 of the
 * License, or any later version.
 * <p/>
 * This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without
 * even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
 * Lesser General Public License for more details. A copy of the GNU Lesser General Public License
 * is distributed along with this program and can be found at
 * <http://www.gnu.org/licenses/lgpl.html>.
 */
package ddf.geo.formatter;

import java.util.ArrayList;
import java.util.Arrays;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

import org.apache.abdera.ext.geo.Position;

import com.vividsolutions.jts.geom.Geometry;
import com.vividsolutions.jts.geom.LinearRing;

public class Polygon extends MultiPoint {

    public static final String TYPE = "Polygon";

    public Polygon(Geometry geometry) {
        super(geometry);

    }

    /**
     *
     * @param coordinates
     *            a List of coordinates formatted in the GeoJSON Array equivalent
     * @return
     */
    public static CompositeGeometry toCompositeGeometry(List coordinates) {
        return new Polygon(buildPolygon(coordinates));
    }

    protected static com.vividsolutions.jts.geom.Polygon buildPolygon(List coordinates) {

        // according to the GeoJson specification, first ring is the exterior
        LinearRing exterior = GEOMETRY_FACTORY
                .createLinearRing(getCoordinates((List) coordinates.get(0)));

        LinearRing[] interiorHoles = new LinearRing[coordinates.size() - 1];

        for (int i = 1; i < coordinates.size(); i++) {
            interiorHoles[i - 1] = GEOMETRY_FACTORY
                    .createLinearRing(getCoordinates((List) coordinates.get(i)));
        }

        return GEOMETRY_FACTORY.createPolygon(exterior, interiorHoles);
    }

    @Override
    public Map toJsonMap() {
        Map map = new HashMap();

        if (TYPE.equals(geometry.getGeometryType())) {

            map.put(TYPE_KEY, TYPE);

            List linearRingsList = buildJsonPolygon((com.vividsolutions.jts.geom.Polygon) geometry);

            map.put(COORDINATES_KEY, linearRingsList);

        } else {
            throw new UnsupportedOperationException("Geometry is not a " + TYPE);
        }

        return map;

    }

    protected List buildJsonPolygon(com.vividsolutions.jts.geom.Polygon polygon) {
        List linearRingsList = new ArrayList();

        // According GeoJSON spec, first LinearRing is the exterior ring
        linearRingsList.add(buildCoordinatesList(polygon.getExteriorRing().getCoordinates()));

        for (int i = 0; i < polygon.getNumInteriorRing(); i++) {
            linearRingsList.add(buildCoordinatesList(polygon.getInteriorRingN(i).getCoordinates()));
        }
        return linearRingsList;
    }

    @Override
    public List<Position> toGeoRssPositions() {

        org.apache.abdera.ext.geo.Coordinates coords = getPolygonCoordinates(
                (com.vividsolutions.jts.geom.Polygon) geometry);

        return Arrays.asList((Position) (new org.apache.abdera.ext.geo.Polygon(coords)));

    }

    protected org.apache.abdera.ext.geo.Coordinates getPolygonCoordinates(
            com.vividsolutions.jts.geom.Polygon polygon) {

        org.apache.abdera.ext.geo.Coordinates coords = new org.apache.abdera.ext.geo.Coordinates();

        // it does not look like http://georss.org/simple or
        // http://georss.org/gml can handle
        // interior rings
        for (com.vividsolutions.jts.geom.Coordinate jtsCoordinate : polygon.getExteriorRing()
                .getCoordinates()) {

            coords.add(convert(jtsCoordinate));

        }
        return coords;
    }
}