Import & export users + improved user state tracking.

platform-independent/java/algorithm/src/main/java/com/lyndir/masterpassword/MPMasterKey.java

@@ -44,7 +44,8 @@ public class MPMasterKey {
 
     /**
      * @param masterPassword The characters of the user's master password.
-     *                       <b>Note: this method destroys the contents of the array.</b>
+     *
+     * @apiNote This method destroys the contents of the {@code masterPassword} array.
      */
     @SuppressWarnings("AssignmentToCollectionOrArrayFieldFromParameter")
     public MPMasterKey(final String fullName, final char[] masterPassword) {

platform-independent/java/gui/build.gradle

@@ -5,7 +5,7 @@ plugins {
 }
 
 description = 'Master Password GUI'
-mainClassName = 'com.lyndir.masterpassword.gui.Main'
+mainClassName = 'com.lyndir.masterpassword.gui.MasterPassword'
 
 dependencies {
     implementation group: 'com.lyndir.lhunath.opal', name: 'opal-system', version: '1.7-p2'

platform-independent/java/gui/src/main/java/com/lyndir/masterpassword/gui/GUI.java

@@ -0,0 +1,26 @@
+package com.lyndir.masterpassword.gui;
+
+import com.lyndir.lhunath.opal.system.logging.Logger;
+import com.lyndir.masterpassword.gui.util.Platform;
+import com.lyndir.masterpassword.gui.util.Res;
+import com.lyndir.masterpassword.gui.view.MasterPasswordFrame;
+
+
+/**
+ * @author lhunath, 2018-07-28
+ */
+public class GUI {
+
+    private static final Logger logger = Logger.get( GUI.class );
+
+    private final MasterPasswordFrame frame = new MasterPasswordFrame();
+
+    public GUI() {
+        Platform.get().installAppForegroundHandler( this::open );
+        Platform.get().installAppReopenHandler( this::open );
+    }
+
+    public void open() {
+        Res.ui( () -> frame.setVisible( true ) );
+    }
+}

platform-independent/java/gui/src/main/java/com/lyndir/masterpassword/gui/MasterPassword.java

@@ -23,10 +23,14 @@ import static com.lyndir.lhunath.opal.system.util.StringUtils.*;
 import com.google.common.base.Charsets;
 import com.google.common.io.ByteSource;
 import com.lyndir.lhunath.opal.system.logging.Logger;
-import com.lyndir.masterpassword.gui.platform.BaseGUI;
+import com.lyndir.lhunath.opal.system.util.ObjectUtils;
+import com.lyndir.masterpassword.model.MPUser;
 import java.io.IOException;
 import java.io.InputStream;
 import java.net.*;
+import java.util.Collection;
+import java.util.concurrent.CopyOnWriteArraySet;
+import javax.annotation.Nullable;
 import javax.swing.*;
 
 
@@ -35,33 +39,42 @@ import javax.swing.*;
  *
  * @author mbillemo
  */
-public final class Main {
+public final class MasterPassword {
 
     @SuppressWarnings("UnusedDeclaration")
-    private static final Logger logger = Logger.get( Main.class );
+    private static final Logger logger = Logger.get( MasterPassword.class );
 
-    public static void main(final String... args) {
+    private static final MasterPassword instance = new MasterPassword();
-//        Thread.setDefaultUncaughtExceptionHandler(
-//                (t, e) -> logger.bug( e, "Uncaught: %s", e.getLocalizedMessage() ) );
 
-        // Try and set the system look & feel, if available.
+    private final Collection<Listener> listeners = new CopyOnWriteArraySet<>();
-        try {
+
-            UIManager.setLookAndFeel( UIManager.getSystemLookAndFeelClassName() );
+    @Nullable
-        }
+    private MPUser<?> activeUser;
-        catch (final UnsupportedLookAndFeelException | ClassNotFoundException | InstantiationException | IllegalAccessException ignored) {
+
+    public static MasterPassword get() {
+        return instance;
     }
 
-        // Check online to see if this version has been superseded.
+    public boolean addListener(final Listener listener) {
-        if (Config.get().checkForUpdates())
+        return listeners.add( listener );
-            checkUpdate();
+    }
 
-        // Create a platform-specific GUI and open it.
+    public boolean removeListener(final Listener listener) {
-        BaseGUI.createPlatformGUI().open();
+        return listeners.remove( listener );
+    }
+
+    public void activateUser(final MPUser<?> user) {
+        if (ObjectUtils.equals( activeUser, user ))
+            return;
+
+        activeUser = user;
+        for (final Listener listener : listeners)
+            listener.onUserSelected( activeUser );
     }
 
     private static void checkUpdate() {
         try {
-            String implementationVersion = Main.class.getPackage().getImplementationVersion();
+            String implementationVersion = MasterPassword.class.getPackage().getImplementationVersion();
             String latestVersion = new ByteSource() {
                 @Override
                 public InputStream openStream()
@@ -90,4 +103,27 @@ public final class Main {
             logger.wrn( e, "Couldn't check for version update." );
         }
     }
+
+    public static void main(final String... args) {
+        //        Thread.setDefaultUncaughtExceptionHandler(
+        //                (t, e) -> logger.bug( e, "Uncaught: %s", e.getLocalizedMessage() ) );
+
+        // Try and set the system look & feel, if available.
+        try {
+            UIManager.setLookAndFeel( UIManager.getSystemLookAndFeelClassName() );
+        }
+        catch (final UnsupportedLookAndFeelException | ClassNotFoundException | InstantiationException | IllegalAccessException ignored) {
+        }
+
+        // Check online to see if this version has been superseded.
+        if (Config.get().checkForUpdates())
+            checkUpdate();
+
+        // Create a platform-specific GUI and open it.
+        new GUI().open();
+    }
+
+    public interface Listener {
+        void onUserSelected(@Nullable MPUser<?> user);
+    }
 }

platform-independent/java/gui/src/main/java/com/lyndir/masterpassword/gui/platform/AppleGUI.java

@@ -1,62 +0,0 @@
-//==============================================================================
-// This file is part of Master Password.
-// Copyright (c) 2011-2017, Maarten Billemont.
-//
-// Master Password is free software: you can redistribute it and/or modify
-// it under the terms of the GNU General Public License as published by
-// the Free Software Foundation, either version 3 of the License, or
-// (at your option) any later version.
-//
-// Master Password is distributed in the hope that it will be useful,
-// but WITHOUT ANY WARRANTY; without even the implied warranty of
-// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
-// GNU General Public License for more details.
-//
-// You can find a copy of the GNU General Public License in the
-// LICENSE file.  Alternatively, see <http://www.gnu.org/licenses/>.
-//==============================================================================
-
-package com.lyndir.masterpassword.gui.platform;
-
-import com.apple.eawt.*;
-import com.google.common.base.Preconditions;
-import com.lyndir.masterpassword.gui.view.MasterPasswordFrame;
-import javax.swing.*;
-
-
-/**
- * @author lhunath, 2014-06-10
- */
-public class AppleGUI extends BaseGUI {
-
-    static Application application = Preconditions.checkNotNull(
-            Application.getApplication(), "Not an Apple Java application." );
-
-    public AppleGUI() {
-        application.addAppEventListener( new AppEventHandler() );
-    }
-
-    @Override
-    protected MasterPasswordFrame createFrame() {
-        MasterPasswordFrame frame = super.createFrame();
-        frame.setDefaultCloseOperation( WindowConstants.HIDE_ON_CLOSE );
-        return frame;
-    }
-
-    private class AppEventHandler implements AppForegroundListener, AppReOpenedListener {
-
-        @Override
-        public void appMovedToBackground(final AppEvent.AppForegroundEvent arg0) {
-        }
-
-        @Override
-        public void appRaisedToForeground(final AppEvent.AppForegroundEvent arg0) {
-            open();
-        }
-
-        @Override
-        public void appReOpened(final AppEvent.AppReOpenedEvent arg0) {
-            open();
-        }
-    }
-}

platform-independent/java/gui/src/main/java/com/lyndir/masterpassword/gui/platform/BaseGUI.java

@@ -1,58 +0,0 @@
-package com.lyndir.masterpassword.gui.platform;
-
-import com.lyndir.lhunath.opal.system.logging.Logger;
-import com.lyndir.lhunath.opal.system.util.TypeUtils;
-import com.lyndir.masterpassword.gui.util.Res;
-import com.lyndir.masterpassword.gui.view.MasterPasswordFrame;
-import java.lang.reflect.InvocationTargetException;
-import java.util.Optional;
-import javax.annotation.Nullable;
-
-
-/**
- * @author lhunath, 2018-07-28
- */
-public class BaseGUI {
-
-    private static final Logger logger = Logger.get( BaseGUI.class );
-
-    private final MasterPasswordFrame frame = createFrame();
-
-    public static BaseGUI createPlatformGUI() {
-        BaseGUI jdk9GUI = construct( "com.lyndir.masterpassword.gui.platform.JDK9GUI" );
-        if (jdk9GUI != null)
-            return jdk9GUI;
-
-        BaseGUI appleGUI = construct( "com.lyndir.masterpassword.gui.platform.AppleGUI" );
-        if (appleGUI != null)
-            return appleGUI;
-
-        // Use platform-independent GUI.
-        return new BaseGUI();
-    }
-
-    @Nullable
-    private static BaseGUI construct(final String typeName) {
-        try {
-            // AppleGUI adds support for macOS features.
-            Optional<Class<BaseGUI>> gui = TypeUtils.loadClass( typeName );
-            if (gui.isPresent())
-                return gui.get().getConstructor().newInstance();
-        }
-        catch (@SuppressWarnings("ErrorNotRethrown") final LinkageError ignored) {
-        }
-        catch (final IllegalAccessException | InstantiationException | NoSuchMethodException | InvocationTargetException e) {
-            throw logger.bug( e );
-        }
-
-        return null;
-    }
-
-    protected MasterPasswordFrame createFrame() {
-        return new MasterPasswordFrame();
-    }
-
-    public void open() {
-        Res.ui( () -> frame.setVisible( true ) );
-    }
-}

platform-independent/java/gui/src/main/java/com/lyndir/masterpassword/gui/platform/JDK9GUI.java

@@ -1,60 +0,0 @@
-//==============================================================================
-// This file is part of Master Password.
-// Copyright (c) 2011-2017, Maarten Billemont.
-//
-// Master Password is free software: you can redistribute it and/or modify
-// it under the terms of the GNU General Public License as published by
-// the Free Software Foundation, either version 3 of the License, or
-// (at your option) any later version.
-//
-// Master Password is distributed in the hope that it will be useful,
-// but WITHOUT ANY WARRANTY; without even the implied warranty of
-// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
-// GNU General Public License for more details.
-//
-// You can find a copy of the GNU General Public License in the
-// LICENSE file.  Alternatively, see <http://www.gnu.org/licenses/>.
-//==============================================================================
-
-package com.lyndir.masterpassword.gui.platform;
-
-import com.lyndir.masterpassword.gui.view.MasterPasswordFrame;
-import java.awt.*;
-import java.awt.desktop.*;
-import javax.swing.*;
-
-
-/**
- * @author lhunath, 2014-06-10
- */
-@SuppressWarnings("Since15")
-public class JDK9GUI extends BaseGUI {
-
-    public JDK9GUI() {
-        Desktop.getDesktop().addAppEventListener( new AppEventHandler() );
-    }
-
-    @Override
-    protected MasterPasswordFrame createFrame() {
-        MasterPasswordFrame frame = super.createFrame();
-        frame.setDefaultCloseOperation( WindowConstants.HIDE_ON_CLOSE );
-        return frame;
-    }
-
-    private class AppEventHandler implements AppForegroundListener, AppReopenedListener {
-
-        @Override
-        public void appRaisedToForeground(final AppForegroundEvent e) {
-            open();
-        }
-
-        @Override
-        public void appMovedToBackground(final AppForegroundEvent e) {
-        }
-
-        @Override
-        public void appReopened(final AppReopenedEvent e) {
-            open();
-        }
-    }
-}

platform-independent/java/gui/src/main/java/com/lyndir/masterpassword/gui/util/Components.java

@@ -21,6 +21,7 @@ package com.lyndir.masterpassword.gui.util;
 import java.awt.*;
 import java.awt.event.ActionEvent;
 import java.awt.event.ActionListener;
+import java.io.File;
 import java.util.Arrays;
 import java.util.Collection;
 import java.util.function.Consumer;
@@ -110,6 +111,29 @@ public abstract class Components {
         return (option < 0)? JOptionPane.CLOSED_OPTION: option;
     }
 
+    @Nullable
+    public static File showLoadDialog(@Nullable final Component owner, final String title) {
+        return showFileDialog( owner, title, FileDialog.LOAD, null );
+    }
+
+    @Nullable
+    public static File showSaveDialog(@Nullable final Component owner, final String title, final String fileName) {
+        return showFileDialog( owner, title, FileDialog.SAVE, fileName );
+    }
+
+    @Nullable
+    private static File showFileDialog(@Nullable final Component owner, final String title,
+                                       final int mode, @Nullable final String fileName) {
+        FileDialog fileDialog = new FileDialog( JOptionPane.getFrameForComponent( owner ), title, mode );
+        fileDialog.setFile( fileName );
+        fileDialog.setLocationRelativeTo( owner );
+        fileDialog.setLocationByPlatform( true );
+        fileDialog.setVisible( true );
+
+        File[] selectedFiles = fileDialog.getFiles();
+        return ((selectedFiles != null) && (selectedFiles.length > 0))? selectedFiles[0]: null;
+    }
+
     public static JDialog showDialog(@Nullable final Component owner, @Nullable final String title, final Container content) {
         JDialog dialog = new JDialog( (owner != null)? SwingUtilities.windowForComponent( owner ): null,
                                       title, Dialog.ModalityType.DOCUMENT_MODAL );

platform-independent/java/gui/src/main/java/com/lyndir/masterpassword/gui/util/Platform.java

@@ -0,0 +1,52 @@
+package com.lyndir.masterpassword.gui.util;
+
+import com.lyndir.lhunath.opal.system.logging.Logger;
+import com.lyndir.lhunath.opal.system.util.TypeUtils;
+import com.lyndir.masterpassword.gui.util.platform.BasePlatform;
+import com.lyndir.masterpassword.gui.util.platform.IPlatform;
+import java.lang.reflect.InvocationTargetException;
+import java.util.Optional;
+import javax.annotation.Nullable;
+
+
+/**
+ * @author lhunath, 2018-07-29
+ */
+public final class Platform {
+
+    private static final Logger    logger = Logger.get( Platform.class );
+    private static final IPlatform activePlatform;
+
+    static {
+        IPlatform tryPlatform;
+        if (null != (tryPlatform = construct( "com.lyndir.masterpassword.gui.util.platform.JDK9Platform" )))
+            activePlatform = tryPlatform;
+
+        else if (null != (tryPlatform = construct( "com.lyndir.masterpassword.gui.util.platform.ApplePlatform" )))
+            activePlatform = tryPlatform;
+
+        else
+            activePlatform = new BasePlatform();
+    }
+
+    @Nullable
+    private static <T> T construct(final String typeName) {
+        try {
+            // AppleGUI adds support for macOS features.
+            Optional<Class<T>> gui = TypeUtils.loadClass( typeName );
+            if (gui.isPresent())
+                return gui.get().getConstructor().newInstance();
+        }
+        catch (@SuppressWarnings("ErrorNotRethrown") final LinkageError ignored) {
+        }
+        catch (final IllegalAccessException | InstantiationException | NoSuchMethodException | InvocationTargetException e) {
+            throw logger.bug( e );
+        }
+
+        return null;
+    }
+
+    public static IPlatform get() {
+        return activePlatform;
+    }
+}

platform-independent/java/gui/src/main/java/com/lyndir/masterpassword/gui/util/Res.java

@@ -136,6 +136,14 @@ public abstract class Res {
             return icon( "media/icon_reset.png" );
         }
 
+        public Icon import_() {
+            return icon( "media/icon_import.png" );
+        }
+
+        public Icon export() {
+            return icon( "media/icon_export.png" );
+        }
+
         public Icon settings() {
             return icon( "media/icon_settings.png" );
         }

platform-independent/java/gui/src/main/java/com/lyndir/masterpassword/gui/util/platform/ApplePlatform.java

@@ -0,0 +1,49 @@
+package com.lyndir.masterpassword.gui.util.platform;
+
+import com.apple.eawt.*;
+import com.apple.eio.FileManager;
+import com.google.common.base.Preconditions;
+import com.google.common.base.Throwables;
+import java.io.File;
+import java.io.FileNotFoundException;
+
+
+/**
+ * @author lhunath, 2018-07-29
+ */
+public class ApplePlatform implements IPlatform {
+
+    static Application application = Preconditions.checkNotNull(
+            Application.getApplication(), "Not an Apple Java application." );
+
+    @Override
+    public boolean installAppForegroundHandler(final Runnable handler) {
+        application.addAppEventListener( new AppForegroundListener() {
+            @Override
+            public void appMovedToBackground(final AppEvent.AppForegroundEvent e) {
+            }
+
+            @Override
+            public void appRaisedToForeground(final AppEvent.AppForegroundEvent e) {
+                handler.run();
+            }
+        } );
+        return true;
+    }
+
+    @Override
+    public boolean installAppReopenHandler(final Runnable handler) {
+        application.addAppEventListener( (AppReOpenedListener) e -> handler.run() );
+        return true;
+    }
+
+    @Override
+    public boolean show(final File file) {
+        try {
+            return FileManager.revealInFinder( file );
+        }
+        catch (final FileNotFoundException ignored) {
+            return false;
+        }
+    }
+}

platform-independent/java/gui/src/main/java/com/lyndir/masterpassword/gui/util/platform/BasePlatform.java

@@ -0,0 +1,25 @@
+package com.lyndir.masterpassword.gui.util.platform;
+
+import java.io.File;
+
+
+/**
+ * @author lhunath, 2018-07-29
+ */
+public class BasePlatform implements IPlatform {
+
+    @Override
+    public boolean installAppForegroundHandler(final Runnable handler) {
+        return false;
+    }
+
+    @Override
+    public boolean installAppReopenHandler(final Runnable handler) {
+        return false;
+    }
+
+    @Override
+    public boolean show(final File file) {
+        return false;
+    }
+}

platform-independent/java/gui/src/main/java/com/lyndir/masterpassword/gui/util/platform/IPlatform.java

@@ -0,0 +1,16 @@
+package com.lyndir.masterpassword.gui.util.platform;
+
+import java.io.File;
+
+
+/**
+ * @author lhunath, 2018-07-29
+ */
+public interface IPlatform {
+
+    boolean installAppForegroundHandler(Runnable handler);
+
+    boolean installAppReopenHandler(Runnable handler);
+
+    boolean show(File file);
+}

platform-independent/java/gui/src/main/java/com/lyndir/masterpassword/gui/util/platform/JDK9Platform.java

@@ -0,0 +1,43 @@
+package com.lyndir.masterpassword.gui.util.platform;
+
+import java.awt.*;
+import java.awt.desktop.*;
+import java.io.File;
+
+
+/**
+ * @author lhunath, 2018-07-29
+ */
+@SuppressWarnings("Since15")
+public class JDK9Platform implements IPlatform {
+
+    @Override
+    public boolean installAppForegroundHandler(final Runnable handler) {
+        Desktop.getDesktop().addAppEventListener( new AppForegroundListener() {
+            @Override
+            public void appRaisedToForeground(final AppForegroundEvent e) {
+                handler.run();
+            }
+
+            @Override
+            public void appMovedToBackground(final AppForegroundEvent e) {
+            }
+        } );
+        return true;
+    }
+
+    @Override
+    public boolean installAppReopenHandler(final Runnable handler) {
+        Desktop.getDesktop().addAppEventListener( (AppReopenedListener) e -> handler.run() );
+        return true;
+    }
+
+    @Override
+    public boolean show(final File file) {
+        if (!file.exists())
+            return false;
+
+        Desktop.getDesktop().browseFileDirectory( file );
+        return true;
+    }
+}

platform-independent/java/gui/src/main/java/com/lyndir/masterpassword/gui/util/platform/package-info.java

@@ -20,6 +20,6 @@
  * @author lhunath, 2018-04-26
  */
 @ParametersAreNonnullByDefault
-package com.lyndir.masterpassword.gui.platform;
+package com.lyndir.masterpassword.gui.util.platform;
 
 import javax.annotation.ParametersAreNonnullByDefault;

platform-independent/java/gui/src/main/java/com/lyndir/masterpassword/gui/view/FilesPanel.java

@@ -3,6 +3,7 @@ package com.lyndir.masterpassword.gui.view;
 import static com.lyndir.masterpassword.util.Utilities.*;
 
 import com.google.common.collect.ImmutableSortedSet;
+import com.lyndir.masterpassword.gui.MasterPassword;
 import com.lyndir.masterpassword.gui.util.*;
 import com.lyndir.masterpassword.model.MPUser;
 import com.lyndir.masterpassword.model.impl.MPFileUser;
@@ -18,15 +19,13 @@ import javax.swing.*;
  * @author lhunath, 2018-07-14
  */
 @SuppressWarnings("serial")
-public class FilesPanel extends JPanel implements MPFileUserManager.Listener {
+public class FilesPanel extends JPanel implements MPFileUserManager.Listener, MasterPassword.Listener {
-
-    private final Collection<Listener> listeners = new CopyOnWriteArraySet<>();
 
     private final JButton avatarButton = Components.button( Res.icons().avatar( 0 ), event -> setAvatar(),
                                                             "Click to change the user's avatar." );
 
     private final CollectionListModel<MPUser<?>> usersModel =
-            CollectionListModel.<MPUser<?>>copy( MPFileUserManager.get().getFiles() ).selection( this::setUser );
+            CollectionListModel.<MPUser<?>>copy( MPFileUserManager.get().getFiles() ).selection( MasterPassword.get()::activateUser );
     private final JComboBox<? extends MPUser<?>> userField  =
             Components.comboBox( usersModel, user -> ifNotNull( user, MPUser::getFullName ) );
 
@@ -50,10 +49,7 @@ public class FilesPanel extends JPanel implements MPFileUserManager.Listener {
         add( userField );
 
         MPFileUserManager.get().addListener( this );
-    }
+        MasterPassword.get().addListener( this );
-
-    public boolean addListener(final Listener listener) {
-        return listeners.add( listener );
     }
 
     private void setAvatar() {
@@ -65,20 +61,14 @@ public class FilesPanel extends JPanel implements MPFileUserManager.Listener {
         avatarButton.setIcon( Res.icons().avatar( selectedUser.getAvatar() ) );
     }
 
-    public void setUser(@Nullable final MPUser<?> user) {
-        avatarButton.setIcon( Res.icons().avatar( (user == null)? 0: user.getAvatar() ) );
-
-        for (final Listener listener : listeners)
-            listener.onUserSelected( user );
-    }
-
     @Override
     public void onFilesUpdated(final ImmutableSortedSet<MPFileUser> files) {
         usersModel.set( files );
     }
 
-    public interface Listener {
+    @Override
-
+    public void onUserSelected(@Nullable final MPUser<?> user) {
-        void onUserSelected(@Nullable MPUser<?> user);
+        usersModel.setSelectedItem( user );
+        avatarButton.setIcon( Res.icons().avatar( (user == null)? 0: user.getAvatar() ) );
     }
 }

platform-independent/java/gui/src/main/java/com/lyndir/masterpassword/gui/view/MasterPasswordFrame.java

@@ -3,10 +3,12 @@ package com.lyndir.masterpassword.gui.view;
 import com.lyndir.lhunath.opal.system.logging.Logger;
 import com.lyndir.masterpassword.gui.util.Components;
 import com.lyndir.masterpassword.gui.util.Res;
+import com.lyndir.masterpassword.model.MPUser;
 import com.lyndir.masterpassword.model.impl.MPFileUserManager;
 import java.awt.*;
 import java.awt.event.ComponentAdapter;
 import java.awt.event.ComponentEvent;
+import javax.annotation.Nullable;
 import javax.swing.*;
 import javax.swing.border.BevelBorder;
 
@@ -40,8 +42,6 @@ public class MasterPasswordFrame extends JFrame {
                 BorderFactory.createBevelBorder( BevelBorder.RAISED, Res.colors().controlBorder(), Res.colors().frameBg() ),
                 Res.colors().controlBg(), BoxLayout.PAGE_AXIS, userContent ), BorderLayout.CENTER );
 
-        filesPanel.addListener( userContent );
-
         addComponentListener( new ComponentHandler() );
         setPreferredSize( new Dimension( 800, 560 ) );
         setDefaultCloseOperation( DISPOSE_ON_CLOSE );

platform-independent/java/gui/src/main/java/com/lyndir/masterpassword/gui/view/UserContentPanel.java

@@ -8,15 +8,22 @@ import com.google.common.primitives.UnsignedInteger;
 import com.lyndir.lhunath.opal.system.logging.Logger;
 import com.lyndir.lhunath.opal.system.util.ObjectUtils;
 import com.lyndir.masterpassword.*;
+import com.lyndir.masterpassword.gui.MasterPassword;
 import com.lyndir.masterpassword.gui.model.MPNewSite;
 import com.lyndir.masterpassword.gui.util.*;
+import com.lyndir.masterpassword.gui.util.Platform;
 import com.lyndir.masterpassword.model.*;
 import com.lyndir.masterpassword.model.impl.*;
 import java.awt.*;
 import java.awt.datatransfer.StringSelection;
 import java.awt.datatransfer.Transferable;
 import java.awt.event.*;
+import java.io.File;
+import java.io.IOException;
+import java.nio.file.Files;
+import java.nio.file.StandardCopyOption;
 import java.util.*;
+import java.util.Optional;
 import java.util.concurrent.Future;
 import java.util.concurrent.TimeUnit;
 import java.util.function.Consumer;
@@ -31,7 +38,7 @@ import javax.swing.event.DocumentListener;
  * @author lhunath, 2018-07-14
  */
 @SuppressWarnings("SerializableStoresNonSerializable")
-public class UserContentPanel extends JPanel implements FilesPanel.Listener, MPUser.Listener {
+public class UserContentPanel extends JPanel implements MasterPassword.Listener, MPUser.Listener {
 
     private static final Random  random     = new Random();
     private static final Logger  logger     = Logger.get( UserContentPanel.class );
@@ -39,12 +46,14 @@ public class UserContentPanel extends JPanel implements FilesPanel.Listener, MPU
 
     private final JButton addButton    = Components.button( Res.icons().add(), event -> addUser(),
                                                             "Add a new user to Master Password." );
+    private final JButton importButton = Components.button( Res.icons().import_(), event -> importUser(),
+                                                            "Import a user from a backup file into Master Password." );
 
     private final JPanel userToolbar = Components.panel( BoxLayout.PAGE_AXIS );
     private final JPanel siteToolbar = Components.panel( BoxLayout.PAGE_AXIS );
 
     @Nullable
-    private MPUser<?>   activeUser;
+    private MPUser<?>   showingUser;
     private ContentMode contentMode;
 
     public UserContentPanel() {
@@ -53,7 +62,9 @@ public class UserContentPanel extends JPanel implements FilesPanel.Listener, MPU
 
         setLayout( new BoxLayout( this, BoxLayout.PAGE_AXIS ) );
         setBorder( Components.marginBorder() );
-        setUser( null );
+        showUser( null );
+
+        MasterPassword.get().addListener( this );
     }
 
     protected JComponent getUserToolbar() {
@@ -66,52 +77,52 @@ public class UserContentPanel extends JPanel implements FilesPanel.Listener, MPU
 
     @Override
     public void onUserSelected(@Nullable final MPUser<?> user) {
-        setUser( user );
+        showUser( user );
     }
 
     @Override
     public void onUserUpdated(final MPUser<?> user) {
-        setUser( user );
+        showUser( user );
     }
 
     @Override
     public void onUserAuthenticated(final MPUser<?> user) {
-        setUser( user );
+        showUser( user );
     }
 
     @Override
     public void onUserInvalidated(final MPUser<?> user) {
-        setUser( user );
+        showUser( user );
     }
 
-    private void setUser(@Nullable final MPUser<?> user) {
+    private void showUser(@Nullable final MPUser<?> user) {
         Res.ui( () -> {
-            if (activeUser != null)
+            if (showingUser != null)
-                activeUser.removeListener( this );
+                showingUser.removeListener( this );
 
             ContentMode newContentMode = ContentMode.getContentMode( user );
-            if ((newContentMode != contentMode) || !ObjectUtils.equals( activeUser, user )) {
+            if ((newContentMode != contentMode) || !ObjectUtils.equals( showingUser, user )) {
                 userToolbar.removeAll();
                 siteToolbar.removeAll();
                 removeAll();
-                activeUser = user;
+                showingUser = user;
                 switch (contentMode = newContentMode) {
                     case NO_USER:
                         add( new NoUserPanel() );
                         break;
                     case AUTHENTICATE:
-                        add( new AuthenticateUserPanel( Preconditions.checkNotNull( activeUser ) ) );
+                        add( new AuthenticateUserPanel( Preconditions.checkNotNull( showingUser ) ) );
                         break;
                     case AUTHENTICATED:
-                        add( new AuthenticatedUserPanel( Preconditions.checkNotNull( activeUser ) ) );
+                        add( new AuthenticatedUserPanel( Preconditions.checkNotNull( showingUser ) ) );
                         break;
                 }
                 revalidate();
                 transferFocus();
             }
 
-            if (activeUser != null)
+            if (showingUser != null)
-                activeUser.addListener( this );
+                showingUser.addListener( this );
         } );
     }
 
@@ -122,7 +133,70 @@ public class UserContentPanel extends JPanel implements FilesPanel.Listener, MPU
         if (fullName == null)
             return;
 
-        setUser( MPFileUserManager.get().add( fullName.toString() ) );
+        MasterPassword.get().activateUser( MPFileUserManager.get().add( fullName.toString() ) );
+    }
+
+    private void importUser() {
+        File importFile = Components.showLoadDialog( this, "Import User File" );
+        if (importFile == null)
+            return;
+
+        try {
+            MPFileUser importUser = MPFileUser.load( importFile );
+            if (importUser == null) {
+                JOptionPane.showMessageDialog(
+                        this, "Not a Master Password file.",
+                        "Import Failed", JOptionPane.ERROR_MESSAGE );
+                return;
+            }
+
+            JPasswordField passwordField = Components.passwordField();
+            if (JOptionPane.OK_OPTION == Components.showDialog( this, "Import User", new JOptionPane( Components.panel(
+                    BoxLayout.PAGE_AXIS,
+                    Components.label( strf( "<html>Enter the master password to import <strong>%s</strong>:</html>",
+                                            importUser.getFullName() ) ),
+                    Components.strut(),
+                    passwordField ), JOptionPane.QUESTION_MESSAGE, JOptionPane.OK_CANCEL_OPTION ) {
+                @Override
+                public void selectInitialValue() {
+                    passwordField.requestFocusInWindow();
+                }
+            } )) {
+                try {
+                    importUser.authenticate( passwordField.getPassword() );
+                    Optional<MPFileUser> existingUser = MPFileUserManager.get().getFiles().stream().filter(
+                            user -> user.getFullName().equalsIgnoreCase( importUser.getFullName() ) ).findFirst();
+                    if (existingUser.isPresent() && (JOptionPane.YES_OPTION != JOptionPane.showConfirmDialog(
+                            this,
+                            strf( "<html>Importing user <strong>%s</strong> from this file will replace the existing user with the imported one.<br>"
+                                  + "Are you sure?<br><br>"
+                                  + "<em>Existing user last modified: %s<br>Imported user last modified: %s</em></html>",
+                                  importUser.getFullName(),
+                                  Res.format( existingUser.get().getLastUsed() ),
+                                  Res.format( importUser.getLastUsed() ) ) )))
+                        return;
+
+                    MasterPassword.get().activateUser( MPFileUserManager.get().add( importUser ) );
+                }
+                catch (final MPIncorrectMasterPasswordException | MPAlgorithmException e) {
+                    JOptionPane.showMessageDialog(
+                            this, e.getLocalizedMessage(),
+                            "Import Failed", JOptionPane.ERROR_MESSAGE );
+                }
+            }
+        }
+        catch (final IOException e) {
+            logger.err( e, "While reading user import file." );
+            JOptionPane.showMessageDialog(
+                    this, strf( "<html>Couldn't read import file:<br><pre>%s</pre></html>.", e.getLocalizedMessage() ),
+                    "Import Failed", JOptionPane.ERROR_MESSAGE );
+        }
+        catch (MPMarshalException e) {
+            logger.err( e, "While parsing user import file." );
+            JOptionPane.showMessageDialog(
+                    this, strf( "<html>Couldn't parse import file:<br><pre>%s</pre></html>.", e.getLocalizedMessage() ),
+                    "Import Failed", JOptionPane.ERROR_MESSAGE );
+        }
     }
 
     private enum ContentMode {
@@ -147,6 +221,7 @@ public class UserContentPanel extends JPanel implements FilesPanel.Listener, MPU
             setLayout( new BoxLayout( this, BoxLayout.PAGE_AXIS ) );
 
             userToolbar.add( addButton );
+            userToolbar.add( importButton );
 
             add( Box.createGlue() );
             add( Components.heading( "Select a user to proceed." ) );
@@ -160,6 +235,8 @@ public class UserContentPanel extends JPanel implements FilesPanel.Listener, MPU
         @Nonnull
         private final MPUser<?> user;
 
+        private final JButton exportButton = Components.button( Res.icons().export(), event -> exportUser(),
+                                                                "Export this user to a backup file." );
         private final JButton deleteButton = Components.button( Res.icons().delete(), event -> deleteUser(),
                                                                 "Delete this user from Master Password." );
         private final JButton resetButton  = Components.button( Res.icons().reset(), event -> resetUser(),
@@ -177,6 +254,8 @@ public class UserContentPanel extends JPanel implements FilesPanel.Listener, MPU
             this.user = user;
 
             userToolbar.add( addButton );
+            userToolbar.add( importButton );
+            userToolbar.add( exportButton );
             userToolbar.add( deleteButton );
             userToolbar.add( resetButton );
 
@@ -197,6 +276,27 @@ public class UserContentPanel extends JPanel implements FilesPanel.Listener, MPU
             add( Box.createGlue() );
         }
 
+        private void exportUser() {
+            MPFileUser fileUser = (user instanceof MPFileUser)? (MPFileUser) user: null;
+            if (fileUser == null)
+                return;
+
+            File exportFile = Components.showSaveDialog( this, "Export User File", fileUser.getFile().getName() );
+            if (exportFile == null)
+                return;
+
+            try {
+                Platform.get().show(
+                        Files.copy( fileUser.getFile().toPath(), exportFile.toPath(),
+                                    StandardCopyOption.REPLACE_EXISTING, StandardCopyOption.COPY_ATTRIBUTES ).toFile() );
+            }
+            catch (final IOException e) {
+                JOptionPane.showMessageDialog(
+                        this, e.getLocalizedMessage(),
+                        "Export Failed", JOptionPane.ERROR_MESSAGE );
+            }
+        }
+
         private void deleteUser() {
             MPFileUser fileUser = (user instanceof MPFileUser)? (MPFileUser) user: null;
             if (fileUser == null)
@@ -372,7 +472,17 @@ public class UserContentPanel extends JPanel implements FilesPanel.Listener, MPU
             sitesModel.registerList( sitesList );
             add( Box.createGlue() );
 
-            user.addListener( this );
+            addComponentListener( new ComponentAdapter() {
+                @Override
+                public void componentShown(final ComponentEvent e) {
+                    user.addListener( AuthenticatedUserPanel.this );
+                }
+
+                @Override
+                public void componentHidden(final ComponentEvent e) {
+                    user.removeListener( AuthenticatedUserPanel.this );
+                }
+            } );
         }
 
         public void showUserPreferences() {

platform-independent/java/model/src/main/java/com/lyndir/masterpassword/model/MPUser.java

@@ -55,12 +55,11 @@ public interface MPUser<S extends MPSite<?>> extends Comparable<MPUser<?>> {
     /**
      * Performs an authentication attempt against the keyID for this user.
      *
-     * Note: If a keyID is not set, authentication will always succeed and the keyID will be set to match the given master password.
-     *
      * @param masterPassword The password to authenticate with.
-     *                       You cannot re-use this array after passing it in, authentication will destroy its contents.
      *
      * @throws MPIncorrectMasterPasswordException If authentication fails due to the given master password not matching the user's keyID.
+     * @apiNote If a keyID is not set, authentication will always succeed and the keyID will be set to match the given master password.
+     * <b>This method destroys the contents of the {@code masterPassword} array.</b>
      */
     void authenticate(char[] masterPassword)
             throws MPIncorrectMasterPasswordException, MPAlgorithmException;
@@ -68,11 +67,10 @@ public interface MPUser<S extends MPSite<?>> extends Comparable<MPUser<?>> {
     /**
      * Performs an authentication attempt against the keyID for this user.
      *
-     * Note: If a keyID is not set, authentication will always succeed and the keyID will be set to match the given key.
-     *
      * @param masterKey The master key to authenticate with.
      *
      * @throws MPIncorrectMasterPasswordException If authentication fails due to the given master password not matching the user's keyID.
+     * @apiNote If a keyID is not set, authentication will always succeed and the keyID will be set to match the given key.
      */
     void authenticate(MPMasterKey masterKey)
             throws MPIncorrectMasterPasswordException, MPKeyUnavailableException, MPAlgorithmException;

platform-independent/java/model/src/main/java/com/lyndir/masterpassword/model/impl/MPBasicUser.java

@@ -37,7 +37,8 @@ import javax.annotation.Nullable;
  */
 public abstract class MPBasicUser<S extends MPBasicSite<?, ?>> extends Changeable implements MPUser<S> {
 
-    protected final Logger        logger    = Logger.get( getClass() );
+    private static final Logger logger = Logger.get( MPBasicUser.class );
+
     private final Set<Listener> listeners = new CopyOnWriteArraySet<>();
 
     private       int         avatar;
@@ -65,7 +66,7 @@ public abstract class MPBasicUser<S extends MPBasicSite<?, ?>> extends Changeabl
 
     @Override
     public void setAvatar(final int avatar) {
-        if (Objects.equals(this.avatar, avatar))
+        if (Objects.equals( this.avatar, avatar ))
             return;
 
         this.avatar = avatar;
@@ -86,7 +87,7 @@ public abstract class MPBasicUser<S extends MPBasicSite<?, ?>> extends Changeabl
 
     @Override
     public void setAlgorithm(final MPAlgorithm algorithm) {
-        if (Objects.equals(this.algorithm, algorithm))
+        if (Objects.equals( this.algorithm, algorithm ))
             return;
 
         this.algorithm = algorithm;

platform-independent/java/model/src/main/java/com/lyndir/masterpassword/model/impl/MPFileUser.java

@@ -18,6 +18,7 @@
 
 package com.lyndir.masterpassword.model.impl;
 
+import com.lyndir.lhunath.opal.system.logging.Logger;
 import com.lyndir.masterpassword.*;
 import com.lyndir.masterpassword.model.MPIncorrectMasterPasswordException;
 import com.lyndir.masterpassword.model.MPUser;
@@ -36,6 +37,8 @@ import org.joda.time.ReadableInstant;
 @SuppressWarnings("ComparableImplementedButEqualsNotOverridden")
 public class MPFileUser extends MPBasicUser<MPFileSite> {
 
+    private static final Logger logger = Logger.get( MPFileUser.class );
+
     @Nullable
     private byte[]                   keyID;
     private File                     path;
@@ -46,13 +49,23 @@ public class MPFileUser extends MPBasicUser<MPFileSite> {
     private ReadableInstant lastUsed;
     private boolean         complete;
 
-    public MPFileUser(final String fullName) {
+    @Nullable
-        this( fullName, null, MPAlgorithm.Version.CURRENT.getAlgorithm() );
+    public static MPFileUser load(final File file)
+            throws IOException, MPMarshalException {
+        for (final MPMarshalFormat format : MPMarshalFormat.values())
+            if (file.getName().endsWith( format.fileSuffix() ))
+                    return format.unmarshaller().readUser( file );
+
+        return null;
     }
 
-    public MPFileUser(final String fullName, @Nullable final byte[] keyID, final MPAlgorithm algorithm) {
+    public MPFileUser(final String fullName, final File path) {
+        this( fullName, null, MPAlgorithm.Version.CURRENT.getAlgorithm(), path );
+    }
+
+    public MPFileUser(final String fullName, @Nullable final byte[] keyID, final MPAlgorithm algorithm, final File path) {
         this( fullName, keyID, algorithm, 0, null, new Instant(),
-              MPMarshaller.ContentMode.PROTECTED, MPMarshalFormat.DEFAULT, MPFileUserManager.get().getPath() );
+              MPMarshaller.ContentMode.PROTECTED, MPMarshalFormat.DEFAULT, path );
     }
 
     public MPFileUser(final String fullName, @Nullable final byte[] keyID, final MPAlgorithm algorithm,
@@ -74,6 +87,10 @@ public class MPFileUser extends MPBasicUser<MPFileSite> {
         return (keyID == null)? null: keyID.clone();
     }
 
+    public void setPath(final File path) {
+        this.path = path;
+    }
+
     @Override
     public void setAlgorithm(final MPAlgorithm algorithm) {
         if (!algorithm.equals( getAlgorithm() ) && (keyID != null)) {
@@ -99,7 +116,7 @@ public class MPFileUser extends MPBasicUser<MPFileSite> {
     }
 
     public void setFormat(final MPMarshalFormat format) {
-        if (Objects.equals(this.format, format))
+        if (Objects.equals( this.format, format ))
             return;
 
         this.format = format;
@@ -111,7 +128,7 @@ public class MPFileUser extends MPBasicUser<MPFileSite> {
     }
 
     public void setContentMode(final MPMarshaller.ContentMode contentMode) {
-        if (Objects.equals(this.contentMode, contentMode))
+        if (Objects.equals( this.contentMode, contentMode ))
             return;
 
         this.contentMode = contentMode;
@@ -123,7 +140,7 @@ public class MPFileUser extends MPBasicUser<MPFileSite> {
     }
 
     public void setDefaultType(final MPResultType defaultType) {
-        if (Objects.equals(this.defaultType, defaultType))
+        if (Objects.equals( this.defaultType, defaultType ))
             return;
 
         this.defaultType = defaultType;
@@ -169,6 +186,19 @@ public class MPFileUser extends MPBasicUser<MPFileSite> {
         }
     }
 
+    public void save() {
+        try {
+            if (isComplete())
+                getFormat().marshaller().marshall( this );
+        }
+        catch (final MPKeyUnavailableException e) {
+            logger.wrn( e, "Cannot write out changes for unauthenticated user: %s.", this );
+        }
+        catch (final IOException | MPMarshalException | MPAlgorithmException e) {
+            logger.err( e, "Unable to write out changes for user: %s", this );
+        }
+    }
+
     @Override
     public void reset() {
         keyID = null;
@@ -183,16 +213,7 @@ public class MPFileUser extends MPBasicUser<MPFileSite> {
 
     @Override
     protected void onChanged() {
-        try {
+        save();
-            if (isComplete())
-                getFormat().marshaller().marshall( this );
-        }
-        catch (final MPKeyUnavailableException e) {
-            logger.wrn( e, "Cannot write out changes for unauthenticated user: %s.", this );
-        }
-        catch (final IOException | MPMarshalException | MPAlgorithmException e) {
-            logger.err( e, "Unable to write out changes for user: %s", this );
-        }
 
         super.onChanged();
     }

platform-independent/java/model/src/main/java/com/lyndir/masterpassword/model/impl/MPFileUserManager.java

@@ -78,14 +78,13 @@ public class MPFileUserManager {
         }
 
         for (final File file : pathFiles)
-            for (final MPMarshalFormat format : MPMarshalFormat.values())
-                if (file.getName().endsWith( format.fileSuffix() ))
             try {
-                        MPFileUser user         = format.unmarshaller().readUser( file );
+                MPFileUser user = MPFileUser.load( file );
+                if (user != null) {
                     MPFileUser previousUser = userByName.put( user.getFullName(), user );
                     if ((previousUser != null) && (previousUser.getFormat().ordinal() > user.getFormat().ordinal()))
                         userByName.put( previousUser.getFullName(), previousUser );
-                        break;
+                }
             }
             catch (final IOException | MPMarshalException e) {
                 logger.err( e, "Couldn't read user from: %s", file );
@@ -95,14 +94,24 @@ public class MPFileUserManager {
     }
 
     public MPFileUser add(final String fullName) {
-        MPFileUser user = new MPFileUser( fullName );
+        return add( new MPFileUser( fullName, getPath() ) );
-        userByName.put( user.getFullName(), user );
+    }
+
+    public MPFileUser add(final MPFileUser user) {
+        user.setPath( getPath() );
+        user.save();
+
+        MPFileUser oldUser = userByName.put( user.getFullName(), user );
+        if (oldUser != null)
+            oldUser.invalidate();
         fireUpdated();
 
         return user;
     }
 
     public void delete(final MPFileUser user) {
+        user.invalidate();
+
         // Remove deleted users.
         File userFile = user.getFile();
         if (userFile.exists() && !userFile.delete())