Clear the password input field and pop a warning when entering bad master password.

MasterPassword/Java/masterpassword-gui/src/main/java/com/lyndir/masterpassword/gui/AuthenticationPanel.java

@@ -46,4 +46,6 @@ public abstract class AuthenticationPanel extends JPanel {
     public Iterable<? extends JButton> getButtons() {
         return ImmutableList.of();
     }
+
+    public abstract void reset();
 }

MasterPassword/Java/masterpassword-gui/src/main/java/com/lyndir/masterpassword/gui/GUI.java

@@ -21,6 +21,7 @@ import com.google.common.base.Charsets;
 import com.google.common.io.*;
 import com.lyndir.lhunath.opal.system.logging.Logger;
 import com.lyndir.lhunath.opal.system.util.TypeUtils;
+import com.lyndir.masterpassword.MasterKey;
 import java.io.*;
 import java.net.URI;
 import java.net.URL;
@@ -103,12 +104,16 @@ public class GUI implements UnlockFrame.SignInCallback {
     public boolean signedIn(final User user) {
         if (!user.hasKey())
             return false;
+        try {
             user.getKey();
-
             passwordFrame = newPasswordFrame( user );
 
             open();
             return true;
+        } catch (MasterKeyException e) {
+            JOptionPane.showMessageDialog( null, e.getLocalizedMessage(), "Sign In Failed", JOptionPane.ERROR_MESSAGE );
+            return false;
+        }
     }
 
     protected PasswordFrame newPasswordFrame(final User user) {

MasterPassword/Java/masterpassword-gui/src/main/java/com/lyndir/masterpassword/gui/IncognitoAuthenticationPanel.java

@@ -64,6 +64,11 @@ public class IncognitoAuthenticationPanel extends AuthenticationPanel implements
         return fullNameField;
     }
 
+    @Override
+    public void reset() {
+        masterPasswordField.setText( "" );
+    }
+
     @Override
     protected User getSelectedUser() {
         return new IncognitoUser( fullNameField.getText(), new String( masterPasswordField.getPassword() ) );

MasterPassword/Java/masterpassword-gui/src/main/java/com/lyndir/masterpassword/gui/MasterKeyException.java

@@ -0,0 +1,11 @@
+package com.lyndir.masterpassword.gui;
+
+/**
+ * @author lhunath, 14-12-17
+ */
+public class MasterKeyException extends Exception {
+
+    public MasterKeyException(final String message) {
+        super( message );
+    }
+}

MasterPassword/Java/masterpassword-gui/src/main/java/com/lyndir/masterpassword/gui/ModelAuthenticationPanel.java

@@ -144,6 +144,11 @@ public class ModelAuthenticationPanel extends AuthenticationPanel implements Ite
         } );
     }
 
+    @Override
+    public void reset() {
+        masterPasswordField.setText( "" );
+    }
+
     private ModelUser[] readConfigUsers() {
         return FluentIterable.from( MPUserFileManager.get().getUsers() ).transform( new Function<MPUser, ModelUser>() {
             @Nullable

MasterPassword/Java/masterpassword-gui/src/main/java/com/lyndir/masterpassword/gui/ModelUser.java

@@ -52,13 +52,13 @@ public class ModelUser extends User {
 
     @NotNull
     @Override
-    public MasterKey getKey() {
+    public MasterKey getKey() throws MasterKeyException {
         MasterKey key = super.getKey();
         if (!model.hasKeyID()) {
             model.setKeyID( key.getKeyID() );
             MPUserFileManager.get().save();
         } else if (!model.hasKeyID( key.getKeyID() ))
-            throw new IllegalStateException( strf( "Incorrect master password for user: %s", getFullName() ) );
+            throw new MasterKeyException( strf( "Incorrect master password for user: %s", getFullName() ) );
 
         return key;
     }

MasterPassword/Java/masterpassword-gui/src/main/java/com/lyndir/masterpassword/gui/UnlockFrame.java

@@ -18,6 +18,7 @@ public class UnlockFrame extends JFrame {
     private final JPanel                       root;
     private final JButton                      signInButton;
     private final JPanel                       authenticationContainer;
+    private       AuthenticationPanel authenticationPanel;
     private       boolean                      incognito;
     public        User                         user;
 
@@ -64,7 +65,6 @@ public class UnlockFrame extends JFrame {
     private void createAuthenticationPanel() {
         authenticationContainer.removeAll();
 
-        final AuthenticationPanel authenticationPanel;
         if (incognito) {
             authenticationPanel = new IncognitoAuthenticationPanel( this );
         } else {
@@ -125,13 +125,11 @@ public class UnlockFrame extends JFrame {
     }
 
     void trySignIn(final JComponent... signInComponents) {
-        if (!checkSignIn()) {
+        if (!checkSignIn())
             return;
-        }
 
-        for (JComponent signInComponent : signInComponents) {
+        for (JComponent signInComponent : signInComponents)
             signInComponent.setEnabled( false );
-        }
 
         signInButton.setEnabled( false );
         signInButton.setText( "Signing In..." );
@@ -149,10 +147,10 @@ public class UnlockFrame extends JFrame {
                             return;
                         }
 
+                        authenticationPanel.reset();
                         signInButton.setText( "Sign In" );
-                        for (JComponent signInComponent : signInComponents) {
+                        for (JComponent signInComponent : signInComponents)
                             signInComponent.setEnabled( true );
-                        }
                         checkSignIn();
                     }
                 } );

MasterPassword/Java/masterpassword-gui/src/main/java/com/lyndir/masterpassword/gui/User.java

@@ -3,8 +3,8 @@ package com.lyndir.masterpassword.gui;
 import static com.lyndir.lhunath.opal.system.util.StringUtils.*;
 
 import com.lyndir.masterpassword.MasterKey;
+import java.security.KeyException;
 import javax.annotation.Nonnull;
-import org.jetbrains.annotations.NotNull;
 
 
 /**
@@ -27,12 +27,11 @@ public abstract class User {
         return key != null || (masterPassword != null && !masterPassword.isEmpty());
     }
 
-    @NotNull
     @Nonnull
-    public MasterKey getKey() {
+    public MasterKey getKey() throws MasterKeyException {
         if (key == null) {
             if (!hasKey())
-                throw new IllegalStateException( strf( "Master password unknown for user: %s", getFullName() ) );
+                throw new MasterKeyException( strf( "Master password unknown for user: %s", getFullName() ) );
             key = new MasterKey( getFullName(), getMasterPassword() );
         }