source: josm/src/org/openstreetmap/josm/actions/SaveActionBase.java@ 290

package org.openstreetmap.josm.actions;

import static org.openstreetmap.josm.tools.I18n.tr;

import java.awt.event.ActionEvent;
import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;

import javax.swing.JFileChooser;
import javax.swing.JOptionPane;
import javax.swing.filechooser.FileFilter;

import org.openstreetmap.josm.Main;
import org.openstreetmap.josm.data.osm.OsmPrimitive;
import org.openstreetmap.josm.gui.layer.OsmDataLayer;
import org.openstreetmap.josm.io.OsmWriter;

public abstract class SaveActionBase extends DiskAccessAction {

        private OsmDataLayer layer;

        public SaveActionBase(String name, String iconName, String tooltip, int shortCut, int modifiers, OsmDataLayer layer) {
                super(name, iconName, tooltip, shortCut, modifiers);
                this.layer = layer;
        }

        public void actionPerformed(ActionEvent e) {
                OsmDataLayer layer = this.layer;
                if (layer == null && Main.map != null && Main.map.mapView.getActiveLayer() instanceof OsmDataLayer)
                        layer = (OsmDataLayer)Main.map.mapView.getActiveLayer();
                if (layer == null)
                        layer = Main.main.editLayer();

                if (!checkSaveConditions(layer))
                        return;

                
                File file = getFile(layer);
                if (file == null)
                        return;

                save(file, layer);

                layer.name = file.getName();
                layer.associatedFile = file;
                Main.parent.repaint();
        }
        
        protected abstract File getFile(OsmDataLayer layer);

        /**
         * Checks whether it is ok to launch a save (whether we have data,
         * there is no conflict etc...)
         * @return <code>true</code>, if it is save to save.
         */
        public boolean checkSaveConditions(OsmDataLayer layer) {
        if (Main.map == null) {
                JOptionPane.showMessageDialog(Main.parent, tr("No document open so nothing to save."));
                return false;
        }
        if (isDataSetEmpty(layer) && JOptionPane.NO_OPTION == JOptionPane.showConfirmDialog(Main.parent,tr("The document contains no data. Save anyway?"), tr("Empty document"), JOptionPane.YES_NO_OPTION))
                return false;
        if (!Main.map.conflictDialog.conflicts.isEmpty()) {
                int answer = JOptionPane.showConfirmDialog(Main.parent, 
                                tr("There are unresolved conflicts. Conflicts will not be saved and handled as if you rejected all. Continue?"),tr("Conflicts"), JOptionPane.YES_NO_OPTION);
                if (answer != JOptionPane.YES_OPTION)
                        return false;
        }
        return true;
    }

        public static File openFileDialog() {
        JFileChooser fc = createAndOpenFileChooser(false, false);
        if (fc == null)
                return null;
    
        File file = fc.getSelectedFile();
    
        String fn = file.getPath();
        if (fn.indexOf('.') == -1) {
                FileFilter ff = fc.getFileFilter();
                if (ff instanceof ExtensionFileFilter)
                        fn = "." + ((ExtensionFileFilter)ff).defaultExtension;
                else
                        fn += ".osm";
                file = new File(fn);
        }
        return file;
    }
        
        public static void save(File file, OsmDataLayer layer) {
            try {
                        if (ExtensionFileFilter.filters[ExtensionFileFilter.GPX].acceptName(file.getPath())) {
                                GpxExportAction.exportGpx(file, layer);
                        } else if (ExtensionFileFilter.filters[ExtensionFileFilter.OSM].acceptName(file.getPath())) {
                                OsmWriter.output(new FileOutputStream(file), new OsmWriter.All(layer.data, false));
                        } else if (ExtensionFileFilter.filters[ExtensionFileFilter.CSV].acceptName(file.getPath())) {
                                JOptionPane.showMessageDialog(Main.parent, tr("CSV output not supported yet."));
                                return;
                        } else {
                                JOptionPane.showMessageDialog(Main.parent, tr("Unknown file extension."));
                                return;
                        }
                        ((OsmDataLayer)layer).cleanData(null, false);
                } catch (IOException e) {
                        e.printStackTrace();
                        JOptionPane.showMessageDialog(Main.parent, tr("An error occurred while saving.")+"\n"+e.getMessage());
                }
    }
        
        /**
         * Check the data set if it would be empty on save. It is empty, if it contains
         * no objects (after all objects that are created and deleted without beeing 
         * transfered to the server have been removed).
         *  
         * @return <code>true</code>, if a save result in an empty data set.
         */
        private boolean isDataSetEmpty(OsmDataLayer layer) {
                for (OsmPrimitive osm : layer.data.allNonDeletedPrimitives())
                        if (!osm.deleted || osm.id > 0)
                                return false;
                return true;
        }
}