/* JToggleButton.java -- 
   Copyright (C) 2002, 2004, 2005, 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
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any later version.

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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
General Public License for more details.

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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
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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
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this exception to your version of the library, but you are not
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package javax.swing;

import java.awt.event.ActionEvent;
import java.awt.event.ItemEvent;
import java.awt.event.ItemListener;

import javax.accessibility.Accessible;
import javax.accessibility.AccessibleContext;
import javax.accessibility.AccessibleRole;
import javax.accessibility.AccessibleState;
import javax.swing.plaf.ButtonUI;

/**
 * The <code>JToggleButton</code> component provides a stateful button,
 * which can be either selected or unselected.  This provides the basis
 * for the implementations of radio buttons (<code>JRadioButton</code>)
 * and check boxes (<code>JCheckBox</code>).
 *
 * @author Michael Koch  (konqueror@gmx.de)
 * @author Graydon Hoare  (graydon@redhat.com)
 * @author Andrew John Hughes  (gnu_andrew@member.fsf.org)
 * @see JRadioButton
 * @see JCheckBox
 * @since 1.2
 */
public class JToggleButton extends AbstractButton implements Accessible
{
  /**
   * This class provides accessibility support for the toggle button.
   */
  protected class AccessibleJToggleButton
    extends AccessibleAbstractButton
    implements ItemListener
  {
    private static final long serialVersionUID = -8652952712161229225L;

    /**
     * Constructor for the accessible toggle button.
     */
    public AccessibleJToggleButton()
    {
      super();
      /* Register the accessible toggle button as a listener for item events */
      addItemListener(this);
    }

    /**
     * Returns the accessible role for the toggle button.
     *
     * @return An instance of <code>AccessibleRole</code>, describing
     *         the role of the toggle button.
     */
    public AccessibleRole getAccessibleRole()
    {
      return AccessibleRole.TOGGLE_BUTTON;
    }
    
    /**
     * Monitors the toggle button for state changes and fires accessible
     * property change events when they occur.
     *
     * @param event the event that occurred.
     */
    public void itemStateChanged(ItemEvent event)
    {
        /* Fire a state property change event as the button's state has changed */
        if (event.getStateChange() == ItemEvent.SELECTED)
          {
            /* State has changed from unselected (null) to selected */
            firePropertyChange(ACCESSIBLE_STATE_PROPERTY, null, AccessibleState.SELECTED);
          } 
        else
          {
            /* State has changed from selected to unselected (null) */
            firePropertyChange(ACCESSIBLE_STATE_PROPERTY, AccessibleState.ENABLED, null);
          }
    }
    
  }

  /**
   * The model handles the storage and maintenance of the state of
   * the toggle button.  This follows the same paradigm (the MVC
   * or Model-View-Controller design pattern) employed by
   * other Swing components, where the data associated with a component
   * is stored separately from the display aspects.
   */
  public static class ToggleButtonModel extends DefaultButtonModel
  {
    /**
     * Compatible with Sun's JDK.
     */
    private static final long serialVersionUID = -1589950750899943974L;
    
    /**
     * Sets the pressed state of the button.  The selected state
     * of the button also changes follwing the button being pressed.
     *
     * @param p true if the button is pressed down.
     */
    public void setPressed(boolean p)  
    {
      // cannot change PRESSED state unless button is enabled
      if (! isEnabled())
        return;
      
      // if this call does not represent a CHANGE in state, then return
      if ((p && isPressed()) || (!p && !isPressed()))
        return;

      // The JDK first fires events in the following order:
      // 1. ChangeEvent for selected
      // 2. ChangeEvent for pressed
      // 3. ActionEvent
      // So do we.

      // setPressed(false) == mouse release on us,
      // if we were armed, we flip the selected state.
      if (!p && isArmed())
        {
          setSelected(! isSelected());
        }

      // make the change
      if (p)
        stateMask = stateMask | PRESSED;
      else
        stateMask = stateMask & (~PRESSED);
      
      // notify interested ChangeListeners
      fireStateChanged();

      if (!p && isArmed())
        {
          fireActionPerformed(new ActionEvent(this,
                                              ActionEvent.ACTION_PERFORMED,
                                              actionCommand));
        }
    }
      
      /**
       * Checks if the button is selected.
       * 
       * @return <code>true</code> if the button is selected.
       */
      public boolean isSelected()
      {
        return super.isSelected();
      }
      
      /**
       * Sets the selected state of the button.
       * 
       * @param b true if button is selected
       */
      public void setSelected(boolean b)
      {
        super.setSelected(b);
      }  
  }

  /**
   * Compatible with Sun's JDK.
   */
  private static final long serialVersionUID = -3128248873429850443L;
    
  /**
   * Constructs an unselected toggle button with no text or icon.
   */ 
  public JToggleButton()
  {
    this(null, null, false);
  }

  /**
   * Constructs a toggle button using the labelling, state
   * and icon specified by the supplied action.
   *
   * @param a the action to use to define the properties of the button.
   */
  public JToggleButton(Action a)
  {
    this();
    setAction(a);
  }

  /**
   * Constructs an unselected toggle button with the supplied icon
   * and no text.
   *
   * @param icon the icon to use.
   */
  public JToggleButton(Icon icon)
  { 
    this(null, icon, false);
  }    
  
  /**
   * Constructs a toggle button with the supplied icon and state.
   *
   * @param icon the icon to use.
   * @param selected if true, the toggle button is initially in the
   *        selected state.  Otherwise, the button is unselected.
   */
  public JToggleButton(Icon icon, boolean selected) 
  {
    this(null, icon, selected);
  }
  
  /**
   * Constructs an unselected toggle button using the supplied text
   * and no icon.
   *
   * @param text the text to use.
   */ 
  public JToggleButton(String text)
  {
    this(text, null, false);
  }
      
  /**
   * Constructs a toggle button with the supplied text and state.
   *
   * @param text the text to use.
   * @param selected if true, the toggle button is initially in the
   *        selected state.  Otherwise, the button is unselected.
   */
  public JToggleButton(String text, boolean selected)
  {
    this(text, null, selected);
  }

  /**
   * Constructs an unselected toggle button with the supplied text
   * and icon.
   *
   * @param text the text to use.
   * @param icon the icon to use.
   */
  public JToggleButton(String text, Icon icon)
  {
    this(text, icon, false);
  }

  /**
   * Constructs a toggle button with the supplied text, icon and state.
   *
   * @param text the text to use.
   * @param icon the icon to use.
   * @param selected if true, the toggle button is initially in the
   *        selected state.  Otherwise, the button is unselected.
   */
  public JToggleButton (String text, Icon icon, boolean selected) 
  {
    super();
    setModel(new ToggleButtonModel());  
    init(text, icon);
    model.setSelected(selected);
    setAlignmentX(LEFT_ALIGNMENT);
  }

  /**
   * Gets the AccessibleContext associated with this <code>JToggleButton</code>.
   * The context is created, if necessary.
   *
   * @return the associated context
   */
  public AccessibleContext getAccessibleContext()
  {
    /* Create the context if this is the first request */
    if (accessibleContext == null)
      {
        /* Create the context */
	accessibleContext = new AccessibleJToggleButton();
      }
    return accessibleContext;
  }
  
  /**
   * Returns a string that specifies the name of the Look and Feel
   * class that renders this component.
   *
   * @return The Look and Feel UI class in <code>String</code> form.
   */
  public String getUIClassID()
  {
    return "ToggleButtonUI";
  }
  
  /**
   * Returns a textual representation of this component for debugging.
   * Users should not depend on anything as regards the content or formatting
   * of this string, except for the fact that the returned string may never be
   * null (only empty).
   *
   * @return the component in <code>String</code> form for debugging.
   */
  protected  String paramString()
  {
    return super.paramString();
  }
  
  /**
   * This method resets the toggle button's UI delegate to the default UI for
   * the current look and feel.
   */
  public void updateUI()
  {	
    setUI((ButtonUI)UIManager.getUI(this));
  }

}