source: josm/src/org/openstreetmap/josm/actions/ReverseSegmentAction.java@ 128

/**
 * 
 */
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.util.Collection;
import java.util.LinkedList;

import javax.swing.JOptionPane;

import org.openstreetmap.josm.Main;
import org.openstreetmap.josm.command.ChangeCommand;
import org.openstreetmap.josm.command.Command;
import org.openstreetmap.josm.command.SequenceCommand;
import org.openstreetmap.josm.data.osm.Node;
import org.openstreetmap.josm.data.osm.OsmPrimitive;
import org.openstreetmap.josm.data.osm.Segment;

public final class ReverseSegmentAction extends JosmAction {

    public ReverseSegmentAction() {
        super(tr("Reverse Segments"), "segmentflip", tr("Revert the direction of all selected Segments."), KeyEvent.VK_R, KeyEvent.CTRL_MASK | KeyEvent.SHIFT_MASK);
    }

        public void actionPerformed(ActionEvent e) {
        Collection<OsmPrimitive> sel = Main.ds.getSelected();
        boolean hasSegments = false;
        for (OsmPrimitive osm : sel) {
                if (osm instanceof Segment) {
                        hasSegments = true;
                        break;
                }
        }
        if (!hasSegments) {
                JOptionPane.showMessageDialog(Main.parent, tr("Please select at least one segment."));
                return;
        }
        Collection<Command> c = new LinkedList<Command>();
        for (OsmPrimitive osm : sel) {
                if (!(osm instanceof Segment))
                        continue;
                Segment s = (Segment)osm;
                Segment snew = new Segment(s);
                Node n = snew.from;
                snew.from = snew.to;
                snew.to = n;
                c.add(new ChangeCommand(s, snew));
        }
        Main.main.editLayer().add(new SequenceCommand(tr("Reverse Segments"), c));
        Main.map.repaint();
    }
}