source: josm/trunk/src/org/openstreetmap/josm/actions/CopyAction.java@ 627

// License: GPL. Copyright 2007 by Immanuel Scholz and others
// Author: David Earl
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.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.LinkedList;
import java.util.Collection;

import javax.swing.JOptionPane;

import org.openstreetmap.josm.Main;
import org.openstreetmap.josm.data.SelectionChangedListener;
import org.openstreetmap.josm.data.osm.DataSet;
import org.openstreetmap.josm.data.osm.Relation;
import org.openstreetmap.josm.data.osm.RelationMember;
import org.openstreetmap.josm.data.osm.Node;
import org.openstreetmap.josm.data.osm.OsmPrimitive;
import org.openstreetmap.josm.data.osm.Way;
import org.openstreetmap.josm.data.osm.visitor.Visitor;

public final class CopyAction extends JosmAction implements SelectionChangedListener {

        private LinkedList<JosmAction> listeners;
        
        public CopyAction() {
                super(tr("Copy"), "copy",
                                tr("Copy selected objects to paste buffer."),
                                KeyEvent.VK_C, KeyEvent.CTRL_MASK, true);
                setEnabled(false);
                DataSet.selListeners.add(this);
                listeners = new LinkedList<JosmAction>();
        }

        @Override public void addListener(JosmAction a) {
                listeners.add(a);
        }
        
        public void actionPerformed(ActionEvent e) {
                Collection<OsmPrimitive> sel = Main.ds.getSelected();
                if (sel.isEmpty()) { 
                        JOptionPane.showMessageDialog(Main.parent,
                                        tr("Please select something to copy."));        
                        return;
                }

                /* New pasteBuffer - will be assigned to the global one at the end */
                final DataSet pasteBuffer = new DataSet();
                final HashMap<OsmPrimitive,OsmPrimitive> map = new HashMap<OsmPrimitive,OsmPrimitive>();
                /* temporarily maps old nodes to new so we can do a true deep copy */

                /* scan the selected objects, mapping them to copies; when copying a way or relation, 
                 * the copy references the copies of their child objects */
                new Visitor(){
                        public void visit(Node n) {
                                /* check if already in pasteBuffer - e.g. two ways are selected which share a node; 
                                 * or a way and a node in that way is selected, we'll see it twice, once via the 
                                 * way and once directly; and so on. */
                                if (map.containsKey(n)) { return; }
                                Node nnew = new Node(n);
                                map.put(n, nnew);
                                pasteBuffer.addPrimitive(nnew);
                        }
                        public void visit(Way w) {
                                /* check if already in pasteBuffer - could have come from a relation, and directly etc. */
                                if (map.containsKey(w)) { return; }
                                Way wnew = new Way();
                                wnew.cloneFrom(w);
                                wnew.nodes.clear();
                                List<Node> nodes = new ArrayList<Node>();
                                for (Node n : w.nodes) {
                                        if (! map.containsKey(n)) {
                                                n.visit(this);
                                        }
                                        nodes.add((Node)map.get(n));
                                }
                                wnew.nodes.clear();
                                wnew.nodes.addAll(nodes);
                                pasteBuffer.addPrimitive(wnew);
                        }
                        public void visit(Relation e) {
                                if (map.containsKey(e)) { return; }
                                Relation enew = new Relation(e);
                                List<RelationMember> members = new ArrayList<RelationMember>();
                                for (RelationMember m : e.members) {
                                        if (! map.containsKey(m.member)) {
                                                m.member.visit(this);
                                        }
                                        RelationMember mnew = new RelationMember(m);
                                        mnew.member = map.get(m.member);
                                        members.add(mnew);
                                }
                                enew.members.addAll(members);
                                pasteBuffer.addPrimitive(enew);
                        }
                        public void visitAll() {
                                for (OsmPrimitive osm : Main.ds.getSelected())
                                        osm.visit(this);
                        }
                }.visitAll();

                Main.pasteBuffer = pasteBuffer;
                Main.main.menu.paste.setEnabled(true); /* now we have a paste buffer we can make paste available */
                
                for(JosmAction a : listeners) {
                        a.pasteBufferChanged(Main.pasteBuffer);
                }
        }

        public void selectionChanged(Collection<? extends OsmPrimitive> newSelection) {
                setEnabled(! newSelection.isEmpty());
        }
}