org.mapsforge.poi.exchange.GeoJsonPoiReader.java Source code

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Here is the source code for org.mapsforge.poi.exchange.GeoJsonPoiReader.java

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/*
 * Copyright 2010 mapsforge.org
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * 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 General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */
package org.mapsforge.poi.exchange;

import java.util.ArrayList;
import java.util.Collection;

import org.json.JSONArray;
import org.json.JSONException;
import org.json.JSONObject;
import org.mapsforge.poi.PoiCategory;
import org.mapsforge.poi.PointOfInterest;
import org.mapsforge.poi.persistence.PoiBuilder;

/**
 * Provides methods for generating points of interest from their geo json representation.
 * 
 * @author weise
 * 
 */
public class GeoJsonPoiReader implements IPoiReader {

    private final String geoJsonString;
    private final PoiCategory category;

    /**
     * @param geoJsonString
     *            geo json string containg the point of interest data.
     * @param category
     *            category the point of interests belong to.
     */
    public GeoJsonPoiReader(String geoJsonString, PoiCategory category) {
        this.geoJsonString = geoJsonString;
        this.category = category;
    }

    @Override
    public Collection<PointOfInterest> read() {
        final Collection<PointOfInterest> pois;

        try {
            JSONObject geoJson = new JSONObject(geoJsonString);

            String type = geoJson.getString("type");

            if (type.equals("FeatureCollection")) {
                pois = fromFeatureCollection(geoJson.getJSONArray("features"));
            } else if (type.equals("GeometryCollection")) {
                pois = fromGeometryCollection(geoJson.getJSONArray("geometries"));
            } else {
                throw new IllegalArgumentException("GeoJson of unknown type");
            }
        } catch (JSONException e) {
            throw new IllegalArgumentException(e.getMessage());
        }

        return pois;
    }

    Collection<PointOfInterest> fromFeatureCollection(JSONArray features) throws JSONException {
        ArrayList<PointOfInterest> pois = new ArrayList<PointOfInterest>(features.length());

        for (int i = 0; i < features.length(); i++) {
            pois.add(fromFeature(features.getJSONObject(i)));
        }

        return pois;
    }

    Collection<PointOfInterest> fromGeometryCollection(JSONArray geometries) throws JSONException {
        ArrayList<PointOfInterest> pois = new ArrayList<PointOfInterest>(geometries.length());

        for (int i = 0; i < geometries.length(); i++) {
            pois.add(fromFeature(geometries.getJSONObject(i)));
        }

        return pois;
    }

    PointOfInterest fromFeature(JSONObject feature) throws JSONException {
        String type = feature.getString("type").toString();
        PointOfInterest point;
        String name = null;
        String url = null;
        Long id = null;

        if (type.equals("Feature")) {
            point = fromPoint(feature.getJSONObject("geometry"));

            if (feature.has("properties")) {
                JSONObject properties = feature.getJSONObject("properties");
                if (properties.has("name")) {
                    name = properties.getString("name");
                }
                if (properties.has("url")) {
                    url = properties.getString("url");
                }
                if (properties.has("id")) {
                    id = properties.getLong("id");
                }
            }

        } else {
            throw new IllegalArgumentException();
        }

        return new PoiBuilder(id, point.getLatitude(), point.getLongitude(), this.category).setName(name)
                .setUrl(url).build();
    }

    PointOfInterest fromPoint(JSONObject point) throws JSONException {
        String type = point.getString("type");
        double lat;
        double lng;

        if (type.equals("Point")) {
            JSONArray coords = point.getJSONArray("coordinates");
            lng = coords.getDouble(0);
            lat = coords.getDouble(1);
        } else {
            throw new IllegalArgumentException();
        }

        return new PoiBuilder(0, lat, lng, this.category).build();
    }
}