/* Checkbox.java -- An AWT checkbox widget   Copyright (C) 1999, 2000, 2001, 2002, 2005  Free Software Foundation, Inc.This file is part of GNU Classpath.GNU Classpath is free software; you can redistribute it and/or modifyit under the terms of the GNU General Public License as published bythe 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, butWITHOUT ANY WARRANTY; without even the implied warranty ofMERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNUGeneral Public License for more details.You should have received a copy of the GNU General Public Licensealong with GNU Classpath; see the file COPYING.  If not, write to theFree Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA02110-1301 USA.Linking this library statically or dynamically with other modules ismaking a combined work based on this library.  Thus, the terms andconditions of the GNU General Public License cover the wholecombination.As a special exception, the copyright holders of this library give youpermission to link this library with independent modules to produce anexecutable, regardless of the license terms of these independentmodules, and to copy and distribute the resulting executable underterms of your choice, provided that you also meet, for each linkedindependent module, the terms and conditions of the license of thatmodule.  An independent module is a module which is not derived fromor based on this library.  If you modify this library, you may extendthis exception to your version of the library, but you are notobligated to do so.  If you do not wish to do so, delete thisexception statement from your version. */package java.awt;import java.awt.event.ItemEvent;import java.awt.event.ItemListener;import java.awt.peer.CheckboxPeer;import java.io.Serializable;import javax.accessibility.Accessible;import javax.accessibility.AccessibleAction;import javax.accessibility.AccessibleContext;import javax.accessibility.AccessibleRole;import javax.accessibility.AccessibleState;import javax.accessibility.AccessibleStateSet;import javax.accessibility.AccessibleValue;/** * This class implements a component which has an on/off state.  Two * or more Checkboxes can be grouped by a CheckboxGroup. * * @author Aaron M. Renn (arenn@urbanophile.com) * @author Tom Tromey (tromey@redhat.com) */public class Checkbox extends Component  implements ItemSelectable, Accessible, Serializable{// FIXME: Need readObject/writeObject for this./* * Static Variables */// Serialization Constantprivate static final long serialVersionUID = 7270714317450821763L;/*************************************************************************//* * Instance Variables *//**  * @serial The checkbox group for this checkbox.  */private CheckboxGroup group;/**  * @serial The label on this checkbox.  */private String label;/**  * @serial The state of this checkbox.  * This is package-private to avoid an accessor method.  */boolean state;// The list of listeners for this object.private transient ItemListener item_listeners;  /*   * The number used to generate the name returned by getName.   */  private static transient long next_checkbox_number;/** * This class provides accessibility support for the * checkbox. * * @author Jerry Quinn  (jlquinn@optonline.net) * @author Andrew John Hughes (gnu_andrew@member.fsf.org) */protected class AccessibleAWTCheckbox  extends AccessibleAWTComponent  implements ItemListener, AccessibleAction, AccessibleValue{  /**   * Serialization constant to match JDK 1.5   */  private static final long serialVersionUID = 7881579233144754107L;  /**   * Default constructor which simply calls the   * super class for generic component accessibility   * handling.   */  public AccessibleAWTCheckbox()  {    super();  }  /**   * Captures changes to the state of the checkbox and   * fires appropriate accessible property change events.   *   * @param event the event fired.   * @see java.awt.event.ItemListener#itemStateChanged(java.awt.event.ItemEvent)   */  public void itemStateChanged(ItemEvent event)  {    firePropertyChange(ACCESSIBLE_STATE_PROPERTY,		       state ? null : AccessibleState.CHECKED,                       state ? AccessibleState.CHECKED : null);  }    /**   * Returns an implementation of the <code>AccessibleAction</code>   * interface for this accessible object.  In this case, the   * current instance is simply returned (with a more appropriate   * type), as it also implements the accessible action as well as   * the context.   *   * @return the accessible action associated with this context.   * @see javax.accessibility.AccessibleAction   */  public AccessibleAction getAccessibleAction()  {    return this;  }    /**   * Returns an implementation of the <code>AccessibleValue</code>   * interface for this accessible object.  In this case, the   * current instance is simply returned (with a more appropriate   * type), as it also implements the accessible value as well as   * the context.   *   * @return the accessible value associated with this context.   * @see javax.accessibility.AccessibleValue   */  public AccessibleValue getAccessibleValue()  {    return this;  }    /*    * The following methods are implemented in the JDK (up to   * 1.5) as stubs.  We do likewise here.   */  /**   * Returns the number of actions associated with this accessible   * object.  This default implementation returns 0.   *   * @return the number of accessible actions available.   * @see javax.accessibility.AccessibleAction#getAccessibleActionCount()   */  public int getAccessibleActionCount()  {    // 1.4.1 and 1.5 do this    return 0;  }  /**   * Returns a description of the action with the supplied id.   * This default implementation always returns null.   *   * @param i the id of the action whose description should be   *          retrieved.   * @return a <code>String</code> describing the action.   * @see javax.accessibility.AccessibleAction#getAccessibleActionDescription(int)   */  public String getAccessibleActionDescription(int i)  {    // 1.5 does this    return null;  }  /**   * Executes the action with the specified id.  This   * default implementation simply returns false.   *   * @param i the id of the action to perform.   * @return true if the action was performed.   * @see javax.accessibility.AccessibleAction#doAccessibleAction(int)   */  public boolean doAccessibleAction(int i)  {    // 1.5 does this    return false;  }  /**   * Returns the current value of this accessible object.   * If no value has been set, null is returned.  This   * default implementation always returns null, regardless.   *   * @return the numeric value of this object, or null if   *         no value has been set.   * @see javax.accessibility.AccessibleValue#getCurrentAccessibleValue()   */  public Number getCurrentAccessibleValue()  {    // 1.5 does this    return null;  }  /**   * Sets the current value of this accessible object   * to that supplied.  In this default implementation,   * the value is never set and the method always returns   * false.   *   * @param number the new accessible value.   * @return true if the value was set.   * @see javax.accessibility.AccessibleValue#setCurrentAccessibleValue(java.lang.Number)   */  public boolean setCurrentAccessibleValue(Number number)  {    // 1.5 does this    return false;  }  /**   * Returns the minimum acceptable accessible value used   * by this object, or null if no minimum value exists.   * This default implementation always returns null.   *   * @return the minimum acceptable accessible value, or null   *         if there is no minimum.   * @see javax.accessibility.AccessibleValue#getMinimumAccessibleValue()   */  public Number getMinimumAccessibleValue()  {    return null;  }  /**   * Returns the maximum acceptable accessible value used   * by this object, or null if no maximum value exists.   * This default implementation always returns null.   *   * @return the maximum acceptable accessible value, or null   *         if there is no maximum.   * @see javax.accessibility.AccessibleValue#getMaximumAccessibleValue()   */  public Number getMaximumAccessibleValue()  {    return null;  }    /**   * Returns the role of this accessible object.   *   * @return the instance of <code>AccessibleRole</code>,   *         which describes this object.   * @see javax.accessibility.AccessibleRole   */  public AccessibleRole getAccessibleRole()   {    return AccessibleRole.CHECK_BOX;  }    /**   * Returns the state set of this accessible object.   *   * @return a set of <code>AccessibleState</code>s   *         which represent the current state of the   *         accessible object.   * @see javax.accessibility.AccessibleState   * @see javax.accessibility.AccessibleStateSet   */  public AccessibleStateSet getAccessibleStateSet()  {    AccessibleStateSet set = super.getAccessibleStateSet();    if (state)      set.add(AccessibleState.CHECKED);    return set;  }}/*************************************************************************//* * Constructors *//**  * Initializes a new instance of <code>Checkbox</code> with no label,  * an initial state of off, and that is not part of any checkbox group.  */public Checkbox(){  this("", false, null);}/*************************************************************************//**