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;
009import java.nio.charset.StandardCharsets;
010
011import javax.xml.parsers.ParserConfigurationException;
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.openstreetmap.josm.tools.Logging;
019import org.openstreetmap.josm.tools.Utils;
020import org.xml.sax.Attributes;
021import org.xml.sax.InputSource;
022import org.xml.sax.SAXException;
023
024/**
025 * Parser for OSM history data.
026 *
027 * It is slightly different from {@link OsmReader} because we don't build an internal graph of
028 * {@link org.openstreetmap.josm.data.osm.OsmPrimitive}s. We use objects derived from
029 * {@link HistoryOsmPrimitive} instead and we keep the data in a dedicated {@link HistoryDataSet}.
030 * @since 1670
031 */
032public class OsmHistoryReader {
033
034    private final InputStream in;
035    private final HistoryDataSet data;
036
037    private class Parser extends AbstractParser {
038
039        protected String getCurrentPosition() {
040            if (locator == null)
041                return "";
042            return new StringBuilder().append('(').append(locator.getLineNumber())
043                                      .append(',').append(locator.getColumnNumber()).append(')').toString();
044        }
045
046        @Override
047        protected void throwException(String message) throws SAXException {
048            throw new SAXException(getCurrentPosition() + message);
049        }
050
051        @Override
052        protected void throwException(String message, Exception e) throws SAXException {
053            throw new SAXException(getCurrentPosition() + message, e);
054        }
055
056        @Override
057        public void startElement(String namespaceURI, String localName, String qName, Attributes atts) throws SAXException {
058            doStartElement(qName, atts);
059        }
060
061        @Override
062        public void endElement(String uri, String localName, String qName) throws SAXException {
063            if ("node".equals(qName)
064                    || "way".equals(qName)
065                    || "relation".equals(qName)) {
066                data.put(currentPrimitive);
067            }
068        }
069    }
070
071    /**
072     * Constructs a new {@code OsmHistoryReader}.
073     *
074     * @param source the input stream with the history content as XML document. Must not be null.
075     * @throws IllegalArgumentException if source is {@code null}.
076     */
077    public OsmHistoryReader(InputStream source) {
078        CheckParameterUtil.ensureParameterNotNull(source, "source");
079        this.in = source;
080        this.data = new HistoryDataSet();
081    }
082
083    /**
084     * Parses the content.
085     * @param progressMonitor the progress monitor. Set to {@link NullProgressMonitor#INSTANCE} if null
086     * @return the parsed data
087     * @throws SAXException If any SAX errors occur during processing.
088     * @throws IOException If any IO errors occur.
089     */
090    public HistoryDataSet parse(ProgressMonitor progressMonitor) throws SAXException, IOException {
091        InputSource inputSource = new InputSource(new InputStreamReader(in, StandardCharsets.UTF_8));
092        progressMonitor.beginTask(tr("Parsing OSM history data ..."));
093        try {
094            Utils.parseSafeSAX(inputSource, new Parser());
095        } catch (ParserConfigurationException e) {
096            Logging.error(e); // broken SAXException chaining
097            throw new SAXException(e);
098        } finally {
099            progressMonitor.finishTask();
100        }
101        return data;
102    }
103}