GPXReader.java

/**
 * *****************************************************************************
 * Copyright 2013 Johannes Mitlmeier
 *
 * Licensed under the Apache License, Version 2.0 (the "License"); you may not
 * use this file except in compliance with the License. You may obtain a copy of
 * the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
 * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
 * License for the specific language governing permissions and limitations under
 * the License.
 * ****************************************************************************
 */
package de.fub.agg2graph.input;

import de.fub.agg2graph.structs.GPSPoint;
import de.fub.agg2graph.structs.GPSSegment;
import de.fub.agg2graph.structs.GPSTrack;
import java.io.File;
import java.io.IOException;
import java.util.Collections;
import java.util.Comparator;
import java.util.List;
import java.util.logging.Level;
import java.util.logging.Logger;
import javax.xml.parsers.ParserConfigurationException;
import javax.xml.parsers.SAXParser;
import javax.xml.parsers.SAXParserFactory;
import org.xml.sax.SAXException;

/**
 * Provide access to the structures stored in a gpx file.
 *
 * @author Johannes Mitlmeier
 *
 */
public class GPXReader {

    private static final Logger LOG = Logger.getLogger(GPXReader.class.getName());

    public static List<GPSTrack> getTracks(File sourceFile) {
        GPXPointReaderHandler handler = process(sourceFile);
        if (handler == null) {
            return null;
        }
        return handler.getTracks();
    }

    public static List<GPSSegment> getSegments(File sourceFile) {
        GPXPointReaderHandler handler = process(sourceFile);
        if (handler == null) {
            return null;
        }
        return handler.getSegments();
    }

    private static GPXPointReaderHandler process(File sourceFile) {
        SAXParserFactory factory = SAXParserFactory.newInstance();
        SAXParser saxParser;
        try {
            saxParser = factory.newSAXParser();
            GPXPointReaderHandler handler = new GPXPointReaderHandler();
            saxParser.parse(sourceFile, handler);
            return handler;
        } catch (ParserConfigurationException e) {
            LOG.log(Level.SEVERE, e.getMessage(), e);
        } catch (SAXException e) {
            LOG.log(Level.SEVERE, e.getMessage(), e);
        } catch (IOException e) {
            LOG.log(Level.SEVERE, e.getMessage(), e);
        }
        return null;
    }

    public static List<GPSPoint> getOrderedPoints(File sourceFile)
            throws ParserConfigurationException, SAXException, IOException {
        Comparator<GPSPoint> comparator = new Comparator<GPSPoint>() {
            @Override
            public int compare(GPSPoint o1, GPSPoint o2) {
                return (int) Math.signum(o1.getLon() - o2.getLon());
            }
        };

        SAXParserFactory factory = SAXParserFactory.newInstance();
        SAXParser saxParser = factory.newSAXParser();
        GPXPointReaderHandler handler = new GPXPointReaderHandler();
        saxParser.parse(sourceFile, handler);
        // sort
        List<GPSPoint> result = handler.getPoints();
        Collections.sort(result, comparator);
        return result;
    }
}