source: josm/src/org/openstreetmap/josm/actions/OpenAction.java@ 98

package org.openstreetmap.josm.actions;

import java.awt.event.ActionEvent;
import java.awt.event.InputEvent;
import java.awt.event.KeyEvent;
import java.io.File;
import java.io.FileReader;
import java.io.IOException;
import java.util.Collection;
import java.util.LinkedList;

import javax.swing.JFileChooser;
import javax.swing.JOptionPane;
import javax.swing.KeyStroke;

import org.jdom.JDOMException;
import org.openstreetmap.josm.Main;
import org.openstreetmap.josm.data.osm.DataSet;
import org.openstreetmap.josm.gui.layer.OsmDataLayer;
import org.openstreetmap.josm.gui.layer.RawGpsDataLayer;
import org.openstreetmap.josm.gui.layer.RawGpsDataLayer.GpsPoint;
import org.openstreetmap.josm.io.GpxReader;
import org.openstreetmap.josm.io.OsmReader;
import org.openstreetmap.josm.io.OsmReaderOld;
import org.openstreetmap.josm.io.RawCsvReader;
import org.openstreetmap.josm.io.RawGpsReader;
import org.xml.sax.SAXException;

/**
 * Open a file chooser dialog and select an file to import. Than call the gpx-import
 * driver. Finally open an internal frame into the main window with the gpx data shown.
 * 
 * @author imi
 */
public class OpenAction extends DiskAccessAction {

        /**
         * Create an open action. The name is "Open a file".
         */
        public OpenAction() {
                super("Open", "open", "Open a file.", "Ctrl-O", KeyStroke.getKeyStroke(KeyEvent.VK_O, InputEvent.CTRL_DOWN_MASK));
        }

        public void actionPerformed(ActionEvent e) {
                JFileChooser fc = createAndOpenFileChooser(true, true);
                if (fc == null)
                        return;
                File[] files = fc.getSelectedFiles();
                for (int i = files.length; i > 0; --i)
                        openFile(files[i-1]);
        }

        /**
         * Open the given file.
         */
        public void openFile(File filename) {
                String fn = filename.getName();
                try {
                        if (asRawData(fn)) {
                                Collection<Collection<GpsPoint>> data;
                                if (ExtensionFileFilter.filters[ExtensionFileFilter.GPX].acceptName(fn)) {
                                        data = new RawGpsReader(new FileReader(filename)).parse();
                                } else if (ExtensionFileFilter.filters[ExtensionFileFilter.CSV].acceptName(fn)) {
                                        data = new LinkedList<Collection<GpsPoint>>();
                                        data.add(new RawCsvReader(new FileReader(filename)).parse());
                                } else
                                        throw new IllegalStateException();
                                Main.main.addLayer(new RawGpsDataLayer(data, filename.getName()));
                        } else {
                                DataSet dataSet;
                                if (ExtensionFileFilter.filters[ExtensionFileFilter.GPX].acceptName(fn)) {
                                        JOptionPane.showMessageDialog(Main.parent, "Warning: Soon, it will be no longer possible to open GPX files as osm data. Please convert your files to .osm format.");
                                        dataSet = new GpxReader(new FileReader(filename)).parse();
                                } else if (ExtensionFileFilter.filters[ExtensionFileFilter.OSM].acceptName(fn)) {
                                        try {
                                                // temporary allow loading of old xml format.
                                                dataSet = OsmReader.parseDataSet(new FileReader(filename));
                                        } catch (SAXException x) {
                                                if (x.getMessage().equals("Unknown version null")) {
                                                        int answer = JOptionPane.showConfirmDialog(Main.parent, 
                                                                        fn+" seems to be an old 0.2 API XML file.\n" +
                                                                        "JOSM can try to open it with the old parser. This option\n" +
                                                                        "will not be available in future JOSM version. You should\n" +
                                                                        "immediatly save the file, if successfull imported.",
                                                                        "Load as 0.2 API file?",
                                                                        JOptionPane.YES_NO_OPTION);
                                                        if (answer != JOptionPane.YES_OPTION)
                                                                return;
                                                        dataSet = new OsmReaderOld(new FileReader(filename)).parse();
                                                } else 
                                                        throw x;
                                        }                                       
                                } else if (ExtensionFileFilter.filters[ExtensionFileFilter.CSV].acceptName(fn)) {
                                        JOptionPane.showMessageDialog(Main.parent, fn+": CSV Data import for non-GPS data is not implemented yet.");
                                        return;
                                } else {
                                        JOptionPane.showMessageDialog(Main.parent, fn+": Unknown file extension: "+fn.substring(filename.getName().lastIndexOf('.')+1));
                                        return;
                                }
                                Main.main.addLayer(new OsmDataLayer(dataSet, "Data Layer", true));
                        }
                } catch (SAXException x) {
                        x.printStackTrace();
                        JOptionPane.showMessageDialog(Main.parent, "Error while parsing: "+x.getMessage());
                } catch (JDOMException x) {
                        x.printStackTrace();
                        JOptionPane.showMessageDialog(Main.parent, "Error while parsing: "+x.getMessage());
                } catch (IOException x) {
                        x.printStackTrace();
                        JOptionPane.showMessageDialog(Main.parent, "Could not read '"+fn+"'\n"+x.getMessage());
                }
        }

        /**
         * @return Return whether the file should be opened as raw gps data. May ask the
         * user, if unsure.
         */
        private boolean asRawData(String fn) {
                if (ExtensionFileFilter.filters[ExtensionFileFilter.CSV].acceptName(fn))
                        return true;
                if (!ExtensionFileFilter.filters[ExtensionFileFilter.GPX].acceptName(fn))
                        return false;
                return JOptionPane.YES_OPTION == JOptionPane.showConfirmDialog(
                                Main.parent, "Do you want to open "+fn+" as raw gps data?",
                                "Open as raw data?", JOptionPane.YES_NO_OPTION);
        }
}