001// License: GPL. For details, see LICENSE file.
002package org.openstreetmap.josm.io;
003
004import static org.openstreetmap.josm.tools.I18n.tr;
005
006import java.io.IOException;
007import java.io.InputStream;
008import java.io.InputStreamReader;
009
010import javax.xml.parsers.ParserConfigurationException;
011import javax.xml.parsers.SAXParserFactory;
012
013import org.openstreetmap.josm.data.osm.history.HistoryDataSet;
014import org.openstreetmap.josm.data.osm.history.HistoryOsmPrimitive;
015import org.openstreetmap.josm.gui.progress.NullProgressMonitor;
016import org.openstreetmap.josm.gui.progress.ProgressMonitor;
017import org.openstreetmap.josm.tools.CheckParameterUtil;
018import org.xml.sax.Attributes;
019import org.xml.sax.InputSource;
020import org.xml.sax.SAXException;
021
022/**
023 * Parser for OSM history data.
024 *
025 * It is slightly different from {@link OsmReader} because we don't build an internal graph of
026 * {@link org.openstreetmap.josm.data.osm.OsmPrimitive}s. We use objects derived from
027 * {@link HistoryOsmPrimitive} instead and we keep the data in a dedicated {@link HistoryDataSet}.
028 * @since 1670
029 */
030public class OsmHistoryReader {
031
032    private final InputStream in;
033    private final HistoryDataSet data;
034
035    private class Parser extends AbstractParser {
036
037        protected String getCurrentPosition() {
038            if (locator == null)
039                return "";
040            return "(" + locator.getLineNumber() + "," + locator.getColumnNumber() + ")";
041        }
042
043        protected void throwException(String message) throws SAXException {
044            throw new SAXException(getCurrentPosition() + message);
045        }
046
047        @Override
048        public void startElement(String namespaceURI, String localName, String qName, Attributes atts) throws SAXException {
049            doStartElement(qName, atts);
050        }
051
052        @Override
053        public void endElement(String uri, String localName, String qName) throws SAXException {
054            if (qName.equals("node")
055                    || qName.equals("way")
056                    || qName.equals("relation")) {
057                data.put(currentPrimitive);
058            }
059        }
060    }
061
062    /**
063     * Constructs a new {@code OsmHistoryReader}.
064     *
065     * @param source the input stream with the history content as XML document. Must not be null.
066     * @throws IllegalArgumentException if source is {@code null}.
067     */
068    public OsmHistoryReader(InputStream source) {
069        CheckParameterUtil.ensureParameterNotNull(source, "source");
070        this.in = source;
071        this.data = new HistoryDataSet();
072    }
073
074    /**
075     * Parses the content.
076     * @param progressMonitor the progress monitor. Set to {@link NullProgressMonitor#INSTANCE} if null
077     * @return the parsed data
078     * @throws SAXException If any SAX errors occur during processing.
079     * @throws IOException If any IO errors occur.
080     */
081    public HistoryDataSet parse(ProgressMonitor progressMonitor) throws SAXException, IOException {
082        InputSource inputSource = new InputSource(new InputStreamReader(in, "UTF-8"));
083        progressMonitor.beginTask(tr("Parsing OSM history data ..."));
084        try {
085            SAXParserFactory.newInstance().newSAXParser().parse(inputSource, new Parser());
086        } catch (ParserConfigurationException e) {
087            e.printStackTrace(); // broken SAXException chaining
088            throw new SAXException(e);
089        } finally {
090            progressMonitor.finishTask();
091        }
092        return data;
093    }
094}