source: josm/src/org/openstreetmap/josm/gui/dialogs/UserListDialog.java@ 237

package org.openstreetmap.josm.gui.dialogs;

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

import java.awt.BorderLayout;

import java.awt.event.KeyEvent;
import java.util.Arrays;
import java.util.Collection;
import java.util.Comparator;
import java.util.HashMap;

import javax.swing.DefaultListModel;

import javax.swing.JScrollPane;
import javax.swing.JTable;
import javax.swing.ListSelectionModel;

import javax.swing.table.DefaultTableModel;

import org.openstreetmap.josm.Main;
import org.openstreetmap.josm.data.SelectionChangedListener;
import org.openstreetmap.josm.data.osm.OsmPrimitive;
import org.openstreetmap.josm.data.osm.User;

/**
 * Displays a dialog with all users who have last edited something in the 
 * selection area, along with the number of objects.
 * 
 * @author Frederik Ramm <frederik@remote.org>
 */
public class UserListDialog extends ToggleDialog implements SelectionChangedListener {

        /**
         * The display list.
         */
        private final DefaultTableModel data = new DefaultTableModel() {
                @Override public boolean isCellEditable(int row, int column) {
                        return false;
                }
                @Override public Class<?> getColumnClass(int columnIndex) {
                        return columnIndex == 0 ? String.class : Integer.class;
                }
        };
        private JTable userTable = new JTable(data);
                        
        public UserListDialog() {
                super(tr("Authors"), "userlist", tr("Open a list of people working on the selected objects."), KeyEvent.VK_A, 150);
                
                data.setColumnIdentifiers(new String[]{tr("Author"),tr("# Objects"),"%"});
                userTable.setSelectionMode(ListSelectionModel.SINGLE_SELECTION);
                add(new JScrollPane(userTable), BorderLayout.CENTER);
                selectionChanged(Main.ds.getSelected());
        }

        @Override public void setVisible(boolean b) {
                if (b) {
                        Main.ds.listeners.add(this);
                        selectionChanged(Main.ds.getSelected());
                } else {
                        Main.ds.listeners.remove(this);
                }
                super.setVisible(b);
        }

        /**
         * Called when the selection in the dataset changed.
         * @param newSelection The new selection array.
         */
        public void selectionChanged(Collection<? extends OsmPrimitive> newSelection) {
                
                class UserCount {
                        User user;
                        int count;
                        UserCount(User user, int count) { this.user=user; this.count=count; }
                };
                
                if (data == null)
                        return; // selection changed may be received in base class constructor before init
                
                data.setRowCount(0);
                
                HashMap<User,UserCount> counters = new HashMap<User,UserCount>();
                int all = 0;
                for (OsmPrimitive p : newSelection) {
                        if (p.user != null) {
                                UserCount uc = counters.get(p.user);
                                if (uc == null) 
                                        counters.put(p.user, uc = new UserCount(p.user, 0));
                                uc.count++;
                                all++;
                        }
                }
                UserCount[] ucArr = new UserCount[counters.size()];
                counters.values().toArray(ucArr);
                Arrays.sort(ucArr, new Comparator<UserCount>() {
                        public int compare(UserCount a, UserCount b) { 
                                return (a.count<b.count) ? 1 : (a.count>b.count) ? -1 : 0;
                        };
                });
                
                for (UserCount uc : ucArr) {
                        data.addRow(new Object[] { uc.user.name, uc.count, uc.count * 100 / all });
                }
        }

}