source: josm/src/org/openstreetmap/josm/io/OsmConnection.java@ 98

package org.openstreetmap.josm.io;

import java.awt.Font;
import java.awt.GridBagLayout;
import java.net.Authenticator;
import java.net.HttpURLConnection;
import java.net.PasswordAuthentication;

import javax.swing.BoundedRangeModel;
import javax.swing.JLabel;
import javax.swing.JOptionPane;
import javax.swing.JPanel;
import javax.swing.JPasswordField;
import javax.swing.JTextField;

import org.openstreetmap.josm.Main;
import org.openstreetmap.josm.tools.GBC;

/**
 * Base class that handles common things like authentication for the reader and writer
 * to the osm server.
 * 
 * @author imi
 */
public class OsmConnection {

        protected boolean cancel = false;
        protected HttpURLConnection activeConnection;
        protected JLabel currentAction;
        protected BoundedRangeModel progress;
        
        private static OsmAuth authentication;
        /**
         * Initialize the http defaults and the authenticator.
         */
        static {
                HttpURLConnection.setFollowRedirects(true);
                Authenticator.setDefault(authentication = new OsmAuth());
        }
        
        /**
     * The authentication class handling the login requests.
     */
    private static class OsmAuth extends Authenticator {
        /**
         * Set to true, when the autenticator tried the password once.
         */
        boolean passwordtried = false;
        /**
         * Whether the user cancelled the password dialog
         */
        boolean authCancelled = false;
    
        @Override protected PasswordAuthentication getPasswordAuthentication() {
                String username = Main.pref.get("osm-server.username");
                String password = Main.pref.get("osm-server.password");
                if (passwordtried || username.equals("") || password.equals("")) {
                        JPanel p = new JPanel(new GridBagLayout());
                        p.add(new JLabel("Username"), GBC.std().insets(0,0,10,0));
                        JTextField usernameField = new JTextField(username, 20);
                        p.add(usernameField, GBC.eol());
                        p.add(new JLabel("Password"), GBC.std().insets(0,0,10,0));
                        JPasswordField passwordField = new JPasswordField(password, 20);
                        p.add(passwordField, GBC.eol());
                        JLabel warning = new JLabel("Warning: The password is transferred unencrypted.");
                        warning.setFont(warning.getFont().deriveFont(Font.ITALIC));
                        p.add(warning, GBC.eol());
                        int choice = JOptionPane.showConfirmDialog(Main.parent, p, "Enter Password", JOptionPane.OK_CANCEL_OPTION);
                        if (choice == JOptionPane.CANCEL_OPTION) {
                                authCancelled = true;
                                return null;
                        }
                        username = usernameField.getText();
                        password = String.valueOf(passwordField.getPassword());
                        if (username.equals(""))
                                return null;
                }
                passwordtried = true;
                return new PasswordAuthentication(username, password.toCharArray());
        }
    }

        /**
         * Must be called before each connection attemp to initialize the authentication.
         */
        protected final void initAuthentication() {
                authentication.authCancelled = false;
                authentication.passwordtried = false;
        }
        
        /**
         * @return Whether the connection was cancelled.
         */
        protected final boolean isAuthCancelled() {
                return authentication.authCancelled;
        }

        public void setProgressInformation(JLabel currentAction, BoundedRangeModel progress) {
                this.currentAction = currentAction;
                this.progress = progress;
    }

        public void cancel() {
                currentAction.setText("Aborting...");
        cancel = true;
        if (activeConnection != null) {
                activeConnection.setConnectTimeout(1);
                activeConnection.setReadTimeout(1);
                activeConnection.disconnect();
        }
    }
}