tilt.handler.get.TiltGeoJsonHandler.java Source code

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Here is the source code for tilt.handler.get.TiltGeoJsonHandler.java

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/*
 * This file is part of TILT.
 *
 *  TILT 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 2 of the License, or
 *  (at your option) any later version.
 *
 *  TILT 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 TILT.  If not, see <http://www.gnu.org/licenses/>.
 *  (c) copyright Desmond Schmidt 2015
 */

package tilt.handler.get;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import tilt.exception.TiltException;
import calliope.core.database.*;
import calliope.core.constants.Database;
import calliope.core.constants.JSONKeys;
import tilt.image.Picture;
import tilt.constants.Params;
import tilt.handler.TiltGetHandler;
import org.json.simple.JSONObject;
import org.json.simple.JSONArray;
import org.json.simple.JSONValue;
import tilt.Utils;
import tilt.image.PictureRegistry;

/**
 * Get the GeoJson for an pageid, plus pageid
 * @author desmond
 */
public class TiltGeoJsonHandler extends TiltGetHandler {
    private JSONObject createEmpty() {
        JSONObject empty = new JSONObject();
        empty.put(JSONKeys.TYPE, "Feature");
        JSONObject geometry = new JSONObject();
        geometry.put(JSONKeys.TYPE, "Polygon");
        JSONArray coordinates = new JSONArray();
        JSONArray topLeft = new JSONArray();
        topLeft.add(0.0);
        topLeft.add(0.0);
        JSONArray topRight = new JSONArray();
        topRight.add(100.0);
        topRight.add(0.0);
        JSONArray botLeft = new JSONArray();
        botLeft.add(100.0);
        botLeft.add(100.0);
        JSONArray botRight = new JSONArray();
        botRight.add(0.0);
        botRight.add(100.0);
        coordinates.add(topLeft);
        coordinates.add(topRight);
        coordinates.add(botLeft);
        coordinates.add(botRight);
        geometry.put("coordinates", coordinates);
        empty.put("geometry", geometry);
        JSONObject properties = new JSONObject();
        empty.put("properties", properties);
        return empty;
    }

    /**
     * Get the GeoJson for the current page
     * @param serverName the name of the server
     * @param docid the document id
     * @param pageid the page id
     * @return the GeoJson object
     * @throws DbException 
     */
    protected JSONObject getGeoJson(String serverName, String docid, String pageid) throws TiltException {
        try {
            JSONObject geoJson = null;
            if (docid.equals("null") || pageid.equals("null")) {
                geoJson = createEmpty();
            } else {
                // first see if it is in the database
                Connection conn = Connector.getConnection();
                String doc = conn.getFromDb(Database.TILT, Utils.ensureSlash(docid + "/" + pageid));
                if (doc != null) {
                    geoJson = (JSONObject) JSONValue.parse(doc);
                    geoJson.remove(JSONKeys._ID);
                    geoJson.remove(JSONKeys.DOCID);
                } else // not already there: generate the GeoJson object
                {
                    // create url to retrieve Picture object
                    String url = Utils.getUrl(serverName, docid, pageid);
                    Picture p = PictureRegistry.get(url);
                    if (p != null) {
                        String geoJsonStr = p.getGeoJson();
                        conn.putToDb(tilt.constants.Database.TILT, Utils.ensureSlash(docid + "/" + pageid),
                                geoJsonStr);
                        geoJson = (JSONObject) JSONValue.parse(geoJsonStr);
                    } else // send an empty geojson text
                    {
                        geoJson = createEmpty();
                    }
                }
            }
            return geoJson;
        } catch (Exception e) {
            throw new TiltException(e);
        }
    }

    public void handle(HttpServletRequest request, HttpServletResponse response, String urn) throws TiltException {
        try {
            String docid = request.getParameter(Params.DOCID);
            String pageid = request.getParameter(Params.PAGEID);
            if (docid != null && pageid != null) {
                JSONObject geoJson = getGeoJson(request.getServerName(), docid, pageid);
                response.setContentType("text/plain");
                response.setCharacterEncoding("UTF-8");
                response.getWriter().print(geoJson.toJSONString());
            } else
                throw new Exception("Missing docid or pageid");
        } catch (Exception e) {
            throw new TiltException(e);
        }
    }
}