Adds vetoable selection listeners and made NSD use them to prevent de-selection.

Fixes issue 4126

Change-Id: I07dbbe0ea7afc5907be20c157b6753bc7e32b122
Reviewed-on: http://gerrit.dmdirc.com/1231
Automatic-Compile: DMDirc Local Commits <dmdirc@googlemail.com>
Reviewed-by: Chris Smith <chris@dmdirc.com>

src/com/dmdirc/addons/ui_swing/components/vetoable/VetoableChangeEvent.java

@@ -0,0 +1,60 @@
+/*
+ * Copyright (c) 2006-2010 Chris Smith, Shane Mc Cormack, Gregory Holmes
+ * 
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ * 
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ * 
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ */
+
+package com.dmdirc.addons.ui_swing.components.vetoable;
+
+import javax.swing.event.ChangeEvent;
+
+/**
+ * Vetoable change event.
+ */
+public class VetoableChangeEvent extends ChangeEvent {
+    /**
+     * A version number for this class. It should be changed whenever the class
+     * structure is changed (or anything else that would prevent serialized
+     * objects being unserialized with the new class).
+     */
+    private static final long serialVersionUID = 1;
+    /** New value. */
+    private Object newValue;
+
+    /**
+     * Creates a new vetoable change event.
+     *
+     * @param source Event source
+     * @param newValue New value
+     */
+    public VetoableChangeEvent(final Object source, final Object newValue ) {
+        super(source);
+        this.newValue = newValue;
+    }
+
+    /**
+     * Returns the new value for the event,
+     *
+     * @return New value
+     */
+    public Object getNewValue() {
+        return newValue;
+    }
+
+}

src/com/dmdirc/addons/ui_swing/components/vetoable/VetoableComboBoxModel.java

@@ -0,0 +1,107 @@
+/*
+ * Copyright (c) 2006-2010 Chris Smith, Shane Mc Cormack, Gregory Holmes
+ * 
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ * 
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ * 
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ */
+
+package com.dmdirc.addons.ui_swing.components.vetoable;
+
+import com.dmdirc.util.ListenerList;
+
+import javax.swing.DefaultComboBoxModel;
+
+/**
+ * Vetoable combo box model.
+ */
+public class VetoableComboBoxModel extends DefaultComboBoxModel {
+
+    /**
+     * A version number for this class. It should be changed whenever the class
+     * structure is changed (or anything else that would prevent serialized
+     * objects being unserialized with the new class).
+     */
+    private static final long serialVersionUID = 1;
+    /** Listener list. */
+    private ListenerList listeners = new ListenerList();
+
+    /**
+     * Constructs an empty DefaultComboBoxModel object.
+     */
+    public VetoableComboBoxModel() {
+        super();
+    }
+
+    /**
+     * Constructs a DefaultComboBoxModel object initialized with
+     * an array of objects.
+     *
+     * @param items  an array of Object objects
+     */
+    public VetoableComboBoxModel(final Object[] items) {
+        super(items);
+    }
+
+    /**
+     * Adds a vetaoble selection listener to this model.
+     *
+     * @param l Listener to add
+     */
+    public void addVetoableSelectionListener(
+            final VetoableComboBoxSelectionListener l) {
+        listeners.add(VetoableComboBoxSelectionListener.class, l);
+    }
+
+    /**
+     * Removes a vetoable selection listener from this model.
+     *
+     * @param l Listener to remove
+     */
+    public void removeVetoableSelectionListener(
+            final VetoableComboBoxSelectionListener l) {
+        listeners.remove(VetoableComboBoxSelectionListener.class, l);
+    }
+
+    /**
+     * Fires a vetoable selection change event.
+     *
+     * @param newValue New value
+     *
+     * @return true iif the event is to be vetoed
+     */
+    protected boolean fireVetoableSelectionChange(final Object newValue) {
+        boolean result = true;
+        VetoableChangeEvent event = new VetoableChangeEvent(this, newValue);
+        for (VetoableComboBoxSelectionListener listener :
+            listeners.get(VetoableComboBoxSelectionListener.class)) {
+                result &= listener.selectionChanged(event);
+        }
+        return result;
+    }
+
+    /** {@inheritDoc} */
+    @Override
+    public void setSelectedItem(final Object anItem) {
+        final Object oldItem = getSelectedItem();
+
+        super.setSelectedItem(anItem);
+        if (!fireVetoableSelectionChange(anItem)) {
+            super.setSelectedItem(oldItem);
+        }
+    }
+}

src/com/dmdirc/addons/ui_swing/components/vetoable/VetoableComboBoxSelectionListener.java

@@ -0,0 +1,40 @@
+/*
+ * Copyright (c) 2006-2010 Chris Smith, Shane Mc Cormack, Gregory Holmes
+ * 
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ * 
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ * 
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ */
+
+package com.dmdirc.addons.ui_swing.components.vetoable;
+
+import java.util.EventListener;
+
+/**
+ * Vetoable change listener.
+ */
+public interface VetoableComboBoxSelectionListener extends EventListener {
+
+    /**
+     * A vetoable selection event has occurred.
+     *
+     * @param e Change event
+     *
+     * @return true iif the selection is allowed to happen
+     */
+    boolean selectionChanged(VetoableChangeEvent e);
+}

src/com/dmdirc/addons/ui_swing/dialogs/NewServerDialog.java

@@ -25,12 +25,15 @@ package com.dmdirc.addons.ui_swing.dialogs;
 import com.dmdirc.Server;
 import com.dmdirc.ServerManager;
 import com.dmdirc.addons.ui_swing.MainFrame;
+import com.dmdirc.addons.ui_swing.components.vetoable.VetoableChangeEvent;
 import com.dmdirc.config.Identity;
 import com.dmdirc.config.IdentityManager;
 import com.dmdirc.config.prefs.validator.PortValidator;
 import com.dmdirc.config.prefs.validator.RegexStringValidator;
 import com.dmdirc.addons.ui_swing.components.LoggingSwingWorker;
 import com.dmdirc.addons.ui_swing.components.validating.ValidatingJTextField;
+import com.dmdirc.addons.ui_swing.components.vetoable.VetoableComboBoxModel;
+import com.dmdirc.addons.ui_swing.components.vetoable.VetoableComboBoxSelectionListener;
 import com.dmdirc.addons.ui_swing.dialogs.profiles.ProfileManagerDialog;
 
 import com.dmdirc.logger.ErrorLevel;
@@ -58,7 +61,8 @@ import net.miginfocom.swing.MigLayout;
 /**
  * Dialog that allows the user to enter details of a new server to connect to.
  */
-public final class NewServerDialog extends StandardDialog implements ActionListener {
+public final class NewServerDialog extends StandardDialog implements 
+        ActionListener, VetoableComboBoxSelectionListener {
 
     /**
      * A version number for this class. It should be changed whenever the class
@@ -174,6 +178,8 @@ public final class NewServerDialog extends StandardDialog implements ActionListe
         getCancelButton().addActionListener(this);
         getOkButton().addActionListener(this);
         editProfileButton.addActionListener(this);
+        ((VetoableComboBoxModel) identityField.getModel()).
+                addVetoableSelectionListener(this);
     }
 
     /**
@@ -187,7 +193,7 @@ public final class NewServerDialog extends StandardDialog implements ActionListe
         newServerWindowCheck = new JCheckBox();
         newServerWindowCheck.setSelected(true);
         sslCheck = new JCheckBox();
-        identityField = new JComboBox();
+        identityField = new JComboBox(new VetoableComboBoxModel());
         editProfileButton = new JButton();
 
         setDefaultCloseOperation(WindowConstants.DO_NOTHING_ON_CLOSE);
@@ -266,11 +272,11 @@ public final class NewServerDialog extends StandardDialog implements ActionListe
         dispose();
         openingServer = true;
 
-        final Identity profile =
-                (Identity) identityField.getSelectedItem();
+        final Identity profile = (Identity) identityField.getSelectedItem();
 
         try {
-            final URI address = new URI("irc" + (sslCheck.isSelected() ? "s" : ""), pass, host, port, null, null, null);
+            final URI address = new URI("irc" + (sslCheck.isSelected() ? "s" :
+                ""), pass, host, port, null, null, null);
 
             // Open in a new window?
             if (newServerWindowCheck.isSelected() || ServerManager.getServerManager()
@@ -317,7 +323,7 @@ public final class NewServerDialog extends StandardDialog implements ActionListe
         if (e.getSource() == getOkButton()) {
             save();
         } else if (e.getSource() == editProfileButton) {
-            ProfileManagerDialog.showProfileManagerDialog(mainFrame );
+            ProfileManagerDialog.showProfileManagerDialog(mainFrame);
         } else if (e.getSource() == getCancelButton()) {
             dispose();
         }
@@ -341,4 +347,13 @@ public final class NewServerDialog extends StandardDialog implements ActionListe
             me = null;
         }
     }
+
+    /** {@inheritDoc} */
+    @Override
+    public boolean selectionChanged(final VetoableChangeEvent e) {
+        if (e.getNewValue() == null) {
+            return false;
+        }
+        return true;
+    }
 }