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diff --git a/libjava/classpath/javax/swing/ButtonGroup.java b/libjava/classpath/javax/swing/ButtonGroup.java
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+/* ButtonGroup.java --
+   Copyright (C) 2002, 2006, Free Software Foundation, Inc.
+
+This file is part of GNU Classpath.
+
+GNU Classpath 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 2, or (at your option)
+any later version.
+
+GNU Classpath 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 should have received a copy of the GNU General Public License
+along with GNU Classpath; see the file COPYING.  If not, write to the
+Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
+02110-1301 USA.
+
+Linking this library statically or dynamically with other modules is
+making a combined work based on this library.  Thus, the terms and
+conditions of the GNU General Public License cover the whole
+combination.
+
+As a special exception, the copyright holders of this library give you
+permission to link this library with independent modules to produce an
+executable, regardless of the license terms of these independent
+modules, and to copy and distribute the resulting executable under
+terms of your choice, provided that you also meet, for each linked
+independent module, the terms and conditions of the license of that
+module.  An independent module is a module which is not derived from
+or based on this library.  If you modify this library, you may extend
+this exception to your version of the library, but you are not
+obligated to do so.  If you do not wish to do so, delete this
+exception statement from your version. */
+
+package javax.swing;
+
+import java.io.Serializable;
+import java.util.Enumeration;
+import java.util.Vector;
+
+
+/**
+ * Logically groups a set of buttons, so that only one of the buttons in
+ * a <code>ButtonGroup</code> can be selected at the same time. If one
+ * button in a <code>ButtonGroup</code> is selected, all other buttons
+ * are automatically deselected.
+ *
+ * While <code>ButtonGroup</code> can be used for all buttons that are derived
+ * from {@link AbstractButton}, it is normally only used for
+ * {@link JRadioButton}s, {@link JRadioButtonMenuItem}s and
+ * {@link JToggleButton}s.
+ *
+ * You could use it for {@link JCheckBox}es, but for the sake of usability
+ * this is strongly discouraged because the common expectation of checkboxes
+ * is that the user is allowed to make multiple selections.
+ *
+ * It makes no sense to put {@link JButton}s or {@link JMenuItem}s in
+ * a <code>ButtonGroup</code> because they don't implement the
+ * <code>selected</code> semantics.
+ *
+ * @author original author unknown
+ */
+public class ButtonGroup implements Serializable
+{
+  private static final long serialVersionUID = 4259076101881721375L;
+
+  /** Stores references to the buttons added to this button group. */
+  protected Vector<AbstractButton> buttons = new Vector<AbstractButton>();
+
+  /** The currently selected button model. */
+  ButtonModel sel;
+
+  /**
+   * Creates a new button group.
+   */
+  public ButtonGroup()
+  {
+    // Nothing to do here.
+  }
+
+  /**
+   * Adds a button to this group.  If the button is in the selected state, then:
+   * <ul>
+   *   <li>if the group has no current selection, the new button becomes the
+   *     selected button for the group;</li>
+   *   <li>if the group already has a selected button, the new button is set to
+   *     "not selected".</li>
+   * </ul>
+   *
+   * @param b the button to add (<code>null</code> is ignored).
+   */
+  public void add(AbstractButton b)
+  {
+    if (b == null)
+      return;
+    b.getModel().setGroup(this);
+    if (b.isSelected())
+      {
+        if (sel == null)
+          sel = b.getModel();
+        else
+          b.setSelected(false);
+      }
+    buttons.addElement(b);
+  }
+
+  /**
+   * Removes the specified button from this group.  If the button is the
+   * selected button, the current selection is set to <code>null</code>.
+   * The group for the removed button's model is set to <code>null</code>.
+   *
+   * @param b the button to remove (<code>null</code> is ignored).
+   */
+  public void remove(AbstractButton b)
+  {
+    if (b == null)
+      return;
+    b.getModel().setGroup(null);
+    if (b.getModel() == sel)
+      sel = null;
+    buttons.removeElement(b);
+  }
+
+  /**
+   * Returns the currently added buttons.
+   *
+   * @return <code>Enumeration</code> over all added buttons
+   */
+  public Enumeration<AbstractButton> getElements()
+  {
+    return buttons.elements();
+  }
+
+  /**
+   * Returns the currently selected button model.
+   *
+   * @return the currently selected button model, null if none was selected
+   *         yet
+   */
+  public ButtonModel getSelection()
+  {
+    return sel;
+  }
+
+  /**
+   * Returns the button that has the specified model, or <code>null</code> if
+   * there is no such button in the group.
+   *
+   * @param m  the button model.
+   *
+   * @return The button that has the specified model, or <code>null</code>.
+   */
+  AbstractButton findButton(ButtonModel m)
+  {
+    for (int i = 0; i < buttons.size(); i++)
+      {
+        AbstractButton a = (AbstractButton) buttons.get(i);
+        if (a.getModel() == m)
+          return a;
+      }
+    return null;
+  }
+
+  /**
+   * Sets the currently selected button model. Only one button of a group can
+   * be selected at a time.
+   *
+   * @param m the model to select
+   * @param b true if this button is to be selected, false otherwise
+   */
+  public void setSelected(ButtonModel m, boolean b)
+  {
+    if ((sel != m || b) && (! b || sel == m))
+      return;
+
+    if (b && sel != m)
+      {
+        ButtonModel old = sel;
+        sel = m;
+
+        if (old != null)
+          old.setSelected(false);
+
+        if (m != null)
+          sel.setSelected(true);
+
+        AbstractButton button = findButton(old);
+        if (button != null)
+          button.repaint();
+      }
+    else if (!b && sel == m)
+      m.setSelected(true);
+  }
+
+  /**
+   * Checks if the given <code>ButtonModel</code> is selected in this button
+   * group.
+   *
+   * @param m  the button model (<code>null</code> permitted).
+   *
+   * @return <code>true</code> if <code>m</code> is the selected button model
+   *     in this group, and <code>false</code> otherwise.
+   */
+  public boolean isSelected(ButtonModel m)
+  {
+    return m == sel;
+  }
+
+  /**
+   * Return the number of buttons in this button group.
+   *
+   * @return the number of buttons
+   *
+   * @since 1.3
+   */
+  public int getButtonCount()
+  {
+    return buttons.size();
+  }
+}