source: josm/trunk/src/org/openstreetmap/josm/actions/UpdateDataAction.java@ 1808

// License: GPL. For details, see LICENSE file.
package org.openstreetmap.josm.actions;

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

import java.awt.event.ActionEvent;
import java.awt.event.KeyEvent;
import java.awt.geom.Area;
import java.util.ArrayList;
import java.util.List;

import javax.swing.JOptionPane;

import org.openstreetmap.josm.Main;
import org.openstreetmap.josm.actions.downloadtasks.DownloadOsmTaskList;
import org.openstreetmap.josm.data.osm.DataSource;
import org.openstreetmap.josm.gui.layer.Layer;
import org.openstreetmap.josm.gui.layer.Layer.LayerChangeListener;
import org.openstreetmap.josm.tools.Shortcut;

public class UpdateDataAction extends JosmAction implements LayerChangeListener{
    public UpdateDataAction() {
        super(tr("Update Data"),
                "updatedata",
                tr("Updates the current data layer from the server (re-downloads data)"),
                Shortcut.registerShortcut("file:updatedata",
                        tr("Update Data"),
                        KeyEvent.VK_U,
                        Shortcut.GROUP_HOTKEY),
                        true);
        refreshEnabled();
        Layer.listeners.add(this);
    }

    /**
     * Refreshes the enabled state
     * 
     */
    protected void refreshEnabled() {
        setEnabled(Main.main != null
                && Main.map != null
                && Main.map.mapView !=null
                && Main.map.mapView.getEditLayer() != null
        );
    }

    public void actionPerformed(ActionEvent e) {
        if (! isEnabled())
            return;
        int bboxCount = 0;
        List<Area> areas = new ArrayList<Area>();
        for(DataSource ds : Main.main.createOrGetEditLayer().data.dataSources) {
            areas.add(new Area(ds.bounds.asRect()));
        }

        // The next two blocks removes every intersection from every DataSource Area
        // This prevents downloading the same data numerous times at intersections
        // and also skips smaller bounding boxes that are contained within larger ones
        // entirely.
        for(int i = 0; i < areas.size(); i++) {
            for(int j = i+1; j < areas.size(); j++) {
                areas.get(i).subtract(areas.get(j));
            }
        }

        for(int i = areas.size()-1; i > 0 ; i--) {
            for(int j = i-1; j > 0; j--) {
                areas.get(i).subtract(areas.get(j));
            }
        }

        for(Area a : areas) {
            if(a.isEmpty()) {
                continue;
            }
            bboxCount++;
        }

        if(bboxCount == 0) {
            JOptionPane.showMessageDialog(
                    Main.parent,
                    tr("No data to update found. Have you already opened or downloaded a data layer?"),
                    tr("No data"),
                    JOptionPane.WARNING_MESSAGE
            );
            return;
        }

        new DownloadOsmTaskList().download(false, areas);
    }

    /* ---------------------------------------------------------------------------------- */
    /* Interface LayerChangeListener                                                      */
    /* ---------------------------------------------------------------------------------- */
    public void activeLayerChange(Layer oldLayer, Layer newLayer) {
        refreshEnabled();
    }

    public void layerAdded(Layer newLayer) {
        refreshEnabled();
    }

    public void layerRemoved(Layer oldLayer) {
        refreshEnabled();
    }
}