source: josm/src/org/openstreetmap/josm/gui/PleaseWaitRunnable.java@ 98

package org.openstreetmap.josm.gui;

import java.awt.EventQueue;
import java.awt.GridBagLayout;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.WindowAdapter;
import java.awt.event.WindowEvent;
import java.io.FileNotFoundException;
import java.io.IOException;

import javax.swing.BorderFactory;
import javax.swing.BoundedRangeModel;
import javax.swing.JButton;
import javax.swing.JDialog;
import javax.swing.JLabel;
import javax.swing.JOptionPane;
import javax.swing.JPanel;
import javax.swing.JProgressBar;

import org.jdom.JDOMException;
import org.openstreetmap.josm.Main;
import org.openstreetmap.josm.tools.GBC;
import org.xml.sax.SAXException;

/**
 * Instanced of this thread will display a "Please Wait" message in middle of JOSM
 * to indicate a progress beeing executed.
 *  
 * @author Imi
 */
public abstract class PleaseWaitRunnable implements Runnable {
        public final JDialog pleaseWaitDlg;
        public String errorMessage;

        private final JProgressBar progressBar = new JProgressBar();
        private boolean closeDialogCalled = false;

        protected final JLabel currentAction = new JLabel("Contact OSM server...");
        protected final BoundedRangeModel progress = progressBar.getModel();

        /**
         * Create the runnable object with a given message for the user.
         */
        public PleaseWaitRunnable(String msg) {
                pleaseWaitDlg = new JDialog(JOptionPane.getFrameForComponent(Main.parent), msg, true);
                pleaseWaitDlg.setLayout(new GridBagLayout());
                JPanel pane = new JPanel(new GridBagLayout());
                pane.setBorder(BorderFactory.createEmptyBorder(10,10,10,10));
                pane.add(currentAction, GBC.eol().fill(GBC.HORIZONTAL));
                pane.add(progressBar, GBC.eop().fill(GBC.HORIZONTAL));
                JButton cancel = new JButton("Cancel");
                pane.add(cancel, GBC.eol().anchor(GBC.CENTER));
                pleaseWaitDlg.setContentPane(pane);
                pleaseWaitDlg.setSize(350,100);
                pleaseWaitDlg.setLocationRelativeTo(Main.parent);

                cancel.addActionListener(new ActionListener(){
                        public void actionPerformed(ActionEvent e) {
                                cancel();
                        }
                });
                pleaseWaitDlg.addWindowListener(new WindowAdapter(){
                        @Override public void windowClosing(WindowEvent e) {
                                if (!closeDialogCalled) {
                                        cancel();
                                        closeDialog();
                                }
                        }
                });
        }

        public final void run() {
                try {
                        realRun();
                } catch (SAXException x) {
                        x.printStackTrace();
                        errorMessage = "Error while parsing: "+x.getMessage();
                } catch (JDOMException x) {
                        x.printStackTrace();
                        errorMessage = "Error while parsing: "+x.getMessage();
                } catch (FileNotFoundException x) {
                        x.printStackTrace();
                        errorMessage = "URL not found: " + x.getMessage();
                } catch (IOException x) {
                        x.printStackTrace();
                        errorMessage = x.getMessage();
                } finally {
                        closeDialog();
                }
        }

        /**
         * User pressed cancel button.
         */
        protected abstract void cancel();

        /**
         * Called in the worker thread to do the actual work. When any of the
         * exception is thrown, a message box will be displayed and closeDialog
         * is called. finish() is called in any case.
         */
        protected abstract void realRun() throws SAXException, JDOMException, IOException;

        /**
         * Finish up the data work. Is guaranteed to be called if realRun is called.
         * Finish is called in the gui thread just after the dialog disappeared.
         */
        protected abstract void finish();

        /**
         * Close the dialog. Usually called from worker thread.
         */
        public void closeDialog() {
                if (closeDialogCalled)
                        return;
                closeDialogCalled  = true;
                EventQueue.invokeLater(new Runnable(){
                        public void run() {
                                finish();
                                pleaseWaitDlg.setVisible(false);
                                pleaseWaitDlg.dispose();
                                if (errorMessage != null)
                                        JOptionPane.showMessageDialog(Main.parent, errorMessage);
                        }
                });
        }
}