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 * Copyright (c) 1995, 2013, Oracle and/or its affiliates. All rights reserved.
 * ORACLE PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
 *
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package java.awt;

import java.awt.peer.CheckboxMenuItemPeer;
import java.awt.event.*;
import java.util.EventListener;
import java.io.ObjectOutputStream;
import java.io.ObjectInputStream;
import java.io.IOException;
import javax.accessibility.*;
import sun.awt.AWTAccessor;


/**
 * This class represents a check box that can be included in a menu.
 * Selecting the check box in the menu changes its state from
 * "on" to "off" or from "off" to "on."
 * <p>
 * The following picture depicts a menu which contains an instance
 * of <code>CheckBoxMenuItem</code>:
 * <p>
 * <img src="doc-files/MenuBar-1.gif"
 * alt="Menu labeled Examples, containing items Basic, Simple, Check, and More Examples. The Check item is a CheckBoxMenuItem instance, in the off state."
 * style="float:center; margin: 7px 10px;">
 * <p>
 * The item labeled <code>Check</code> shows a check box menu item
 * in its "off" state.
 * <p>
 * When a check box menu item is selected, AWT sends an item event to
 * the item. Since the event is an instance of <code>ItemEvent</code>,
 * the <code>processEvent</code> method examines the event and passes
 * it along to <code>processItemEvent</code>. The latter method redirects
 * the event to any <code>ItemListener</code> objects that have
 * registered an interest in item events generated by this menu item.
 *
 * @author Sami Shaio
 * @see java.awt.event.ItemEvent
 * @see java.awt.event.ItemListener
 * @since JDK1.0
 */
public class CheckboxMenuItem extends MenuItem implements ItemSelectable, Accessible {

 static {
 /* ensure that the necessary native libraries are loaded */
 Toolkit.loadLibraries();
 if (!GraphicsEnvironment.isHeadless()) {
 initIDs();
 }

 AWTAccessor.setCheckboxMenuItemAccessor(
 new AWTAccessor.CheckboxMenuItemAccessor() {
 public boolean getState(CheckboxMenuItem cmi) {
 return cmi.state;
 }
 });
 }

 /**
 * The state of a checkbox menu item
 * @serial
 * @see #getState()
 * @see #setState(boolean)
 */
 boolean state = false;

 transient ItemListener itemListener;

 private static final String base = "chkmenuitem";
 private static int nameCounter = 0;

 /*
 * JDK 1.1 serialVersionUID
 */
 private static final long serialVersionUID = 6190621106981774043L;

 /**
 * Create a check box menu item with an empty label.
 * The item's state is initially set to "off."
 * @exception HeadlessException if GraphicsEnvironment.isHeadless()
 * returns true
 * @see java.awt.GraphicsEnvironment#isHeadless
 * @since JDK1.1
 */
 public CheckboxMenuItem() throws HeadlessException {
 this("", false);
 }

 /**
 * Create a check box menu item with the specified label.
 * The item's state is initially set to "off."

 * @param label a string label for the check box menu item,
 * or <code>null</code> for an unlabeled menu item.
 * @exception HeadlessException if GraphicsEnvironment.isHeadless()
 * returns true
 * @see java.awt.GraphicsEnvironment#isHeadless
 */
 public CheckboxMenuItem(String label) throws HeadlessException {
 this(label, false);
 }

 /**
 * Create a check box menu item with the specified label and state.
 * @param label a string label for the check box menu item,
 * or <code>null</code> for an unlabeled menu item.
 * @param state the initial state of the menu item, where
 * <code>true</code> indicates "on" and
 * <code>false</code> indicates "off."
 * @exception HeadlessException if GraphicsEnvironment.isHeadless()
 * returns true
 * @see java.awt.GraphicsEnvironment#isHeadless
 * @since JDK1.1
 */
 public CheckboxMenuItem(String label, boolean state)
 throws HeadlessException {
 super(label);
 this.state = state;
 }

 /**
 * Construct a name for this MenuComponent. Called by getName() when
 * the name is null.
 */
 String constructComponentName() {
 synchronized (CheckboxMenuItem.class) {
 return base + nameCounter++;
 }
 }

 /**
 * Creates the peer of the checkbox item. This peer allows us to
 * change the look of the checkbox item without changing its
 * functionality.
 * Most applications do not call this method directly.
 * @see java.awt.Toolkit#createCheckboxMenuItem(java.awt.CheckboxMenuItem)
 * @see java.awt.Component#getToolkit()
 */
 public void addNotify() {
 synchronized (getTreeLock()) {
 if (peer == null)
 peer = Toolkit.getDefaultToolkit().createCheckboxMenuItem(this);
 super.addNotify();
 }
 }

 /**
 * Determines whether the state of this check box menu item
 * is "on" or "off."
 *
 * @return the state of this check box menu item, where
 * <code>true</code> indicates "on" and
 * <code>false</code> indicates "off"
 * @see #setState
 */
 public boolean getState() {
 return state;
 }

 /**
 * Sets this check box menu item to the specified state.
 * The boolean value <code>true</code> indicates "on" while
 * <code>false</code> indicates "off."
 *
 * <p>Note that this method should be primarily used to
 * initialize the state of the check box menu item.
 * Programmatically setting the state of the check box
 * menu item will <i>not</i> trigger
 * an <code>ItemEvent</code>. The only way to trigger an
 * <code>ItemEvent</code> is by user interaction.
 *
 * @param b <code>true</code> if the check box
 * menu item is on, otherwise <code>false</code>
 * @see #getState
 */
 public synchronized void setState(boolean b) {
 state = b;
 CheckboxMenuItemPeer peer = (CheckboxMenuItemPeer)this.peer;
 if (peer != null) {
 peer.setState(b);
 }
 }

 /**
 * Returns the an array (length 1) containing the checkbox menu item
 * label or null if the checkbox is not selected.
 * @see ItemSelectable
 */
 public synchronized Object[] getSelectedObjects() {
 if (state) {
 Object[] items = new Object[1];
 items[0] = label;
 return items;
 }
 return null;
 }

 /**
 * Adds the specified item listener to receive item events from
 * this check box menu item. Item events are sent in response to user
 * actions, but not in response to calls to setState().
 * If l is null, no exception is thrown and no action is performed.
 * <p>Refer to <a href="doc-files/AWTThreadIssues.html#ListenersThreads"
 * >AWT Threading Issues</a> for details on AWT's threading model.
 *
 * @param l the item listener
 * @see #removeItemListener
 * @see #getItemListeners
 * @see #setState
 * @see java.awt.event.ItemEvent
 * @see java.awt.event.ItemListener
 * @since JDK1.1
 */
 public synchronized void addItemListener(ItemListener l) {
 if (l == null) {
 return;
 }
 itemListener = AWTEventMulticaster.add(itemListener, l);
 newEventsOnly = true;
 }

 /**
 * Removes the specified item listener so that it no longer receives
 * item events from this check box menu item.
 * If l is null, no exception is thrown and no action is performed.
 * <p>Refer to <a href="doc-files/AWTThreadIssues.html#ListenersThreads"
 * >AWT Threading Issues</a> for details on AWT's threading model.
 *
 * @param l the item listener
 * @see #addItemListener
 * @see #getItemListeners
 * @see java.awt.event.ItemEvent
 * @see java.awt.event.ItemListener
 * @since JDK1.1
 */
 public synchronized void removeItemListener(ItemListener l) {
 if (l == null) {
 return;
 }
 itemListener = AWTEventMulticaster.remove(itemListener, l);
 }

 /**
 * Returns an array of all the item listeners
 * registered on this checkbox menuitem.
 *
 * @return all of this checkbox menuitem's <code>ItemListener</code>s
 * or an empty array if no item
 * listeners are currently registered
 *
 * @see #addItemListener
 * @see #removeItemListener
 * @see java.awt.event.ItemEvent
 * @see java.awt.event.ItemListener
 * @since 1.4
 */
 public synchronized ItemListener[] getItemListeners() {
 return getListeners(ItemListener.class);
 }

 /**
 * Returns an array of all the objects currently registered
 * as <code><em>Foo</em>Listener</code>s
 * upon this <code>CheckboxMenuItem</code>.
 * <code><em>Foo</em>Listener</code>s are registered using the
 * <code>add<em>Foo</em>Listener</code> method.
 *
 * <p>
 * You can specify the <code>listenerType</code> argument
 * with a class literal, such as
 * <code><em>Foo</em>Listener.class</code>.
 * For example, you can query a
 * <code>CheckboxMenuItem</code> <code>c</code>
 * for its item listeners with the following code:
 *
 * <pre>ItemListener[] ils = (ItemListener[])(c.getListeners(ItemListener.class));</pre>
 *
 * If no such listeners exist, this method returns an empty array.
 *
 * @param listenerType the type of listeners requested; this parameter
 * should specify an interface that descends from
 * <code>java.util.EventListener</code>
 * @return an array of all objects registered as
 * <code><em>Foo</em>Listener</code>s on this checkbox menuitem,
 * or an empty array if no such
 * listeners have been added
 * @exception ClassCastException if <code>listenerType</code>
 * doesn't specify a class or interface that implements
 * <code>java.util.EventListener</code>
 *
 * @see #getItemListeners
 * @since 1.3
 */
 public <T extends EventListener> T[] getListeners(Class<T> listenerType) {
 EventListener l = null;
 if (listenerType == ItemListener.class) {
 l = itemListener;
 } else {
 return super.getListeners(listenerType);
 }
 return AWTEventMulticaster.getListeners(l, listenerType);
 }

 // REMIND: remove when filtering is done at lower level
 boolean eventEnabled(AWTEvent e) {
 if (e.id == ItemEvent.ITEM_STATE_CHANGED) {
 if ((eventMask & AWTEvent.ITEM_EVENT_MASK) != 0 ||
 itemListener != null) {
 return true;
 }
 return false;
 }
 return super.eventEnabled(e);
 }

 /**
 * Processes events on this check box menu item.
 * If the event is an instance of <code>ItemEvent</code>,
 * this method invokes the <code>processItemEvent</code> method.
 * If the event is not an item event,
 * it invokes <code>processEvent</code> on the superclass.
 * <p>
 * Check box menu items currently support only item events.
 * <p>Note that if the event parameter is <code>null</code>
 * the behavior is unspecified and may result in an
 * exception.
 *
 * @param e the event
 * @see java.awt.event.ItemEvent
 * @see #processItemEvent
 * @since JDK1.1
 */
 protected void processEvent(AWTEvent e) {
 if (e instanceof ItemEvent) {
 processItemEvent((ItemEvent)e);
 return;
 }
 super.processEvent(e);
 }

 /**
 * Processes item events occurring on this check box menu item by
 * dispatching them to any registered <code>ItemListener</code> objects.
 * <p>
 * This method is not called unless item events are
 * enabled for this menu item. Item events are enabled
 * when one of the following occurs:
 * <ul>
 * <li>An <code>ItemListener</code> object is registered
 * via <code>addItemListener</code>.
 * <li>Item events are enabled via <code>enableEvents</code>.
 * </ul>
 * <p>Note that if the event parameter is <code>null</code>
 * the behavior is unspecified and may result in an
 * exception.
 *
 * @param e the item event
 * @see java.awt.event.ItemEvent
 * @see java.awt.event.ItemListener
 * @see #addItemListener
 * @see java.awt.MenuItem#enableEvents
 * @since JDK1.1
 */
 protected void processItemEvent(ItemEvent e) {
 ItemListener listener = itemListener;
 if (listener != null) {
 listener.itemStateChanged(e);
 }
 }

 /*
 * Post an ItemEvent and toggle state.
 */
 void doMenuEvent(long when, int modifiers) {
 setState(!state);
 Toolkit.getEventQueue().postEvent(
 new ItemEvent(this, ItemEvent.ITEM_STATE_CHANGED,
 getLabel(),
 state ? ItemEvent.SELECTED :
 ItemEvent.DESELECTED));
 }

 /**
 * Returns a string representing the state of this
 * <code>CheckBoxMenuItem</code>. This
 * method is intended to be used only for debugging purposes, and the
 * content and format of the returned string may vary between
 * implementations. The returned string may be empty but may not be
 * <code>null</code>.
 *
 * @return the parameter string of this check box menu item
 */
 public String paramString() {
 return super.paramString() + ",state=" + state;
 }

 /* Serialization support.
 */

 /*
 * Serial Data Version
 * @serial
 */
 private int checkboxMenuItemSerializedDataVersion = 1;

 /**
 * Writes default serializable fields to stream. Writes
 * a list of serializable <code>ItemListeners</code>
 * as optional data. The non-serializable
 * <code>ItemListeners</code> are detected and
 * no attempt is made to serialize them.
 *
 * @param s the <code>ObjectOutputStream</code> to write
 * @serialData <code>null</code> terminated sequence of
 * 0 or more pairs; the pair consists of a <code>String</code>
 * and an <code>Object</code>; the <code>String</code> indicates
 * the type of object and is one of the following:
 * <code>itemListenerK</code> indicating an
 * <code>ItemListener</code> object
 *
 * @see AWTEventMulticaster#save(ObjectOutputStream, String, EventListener)
 * @see java.awt.Component#itemListenerK
 * @see #readObject(ObjectInputStream)
 */
 private void writeObject(ObjectOutputStream s)
 throws java.io.IOException
 {
 s.defaultWriteObject();

 AWTEventMulticaster.save(s, itemListenerK, itemListener);
 s.writeObject(null);
 }

 /*
 * Reads the <code>ObjectInputStream</code> and if it
 * isn't <code>null</code> adds a listener to receive
 * item events fired by the <code>Checkbox</code> menu item.
 * Unrecognized keys or values will be ignored.
 *
 * @param s the <code>ObjectInputStream</code> to read
 * @serial
 * @see removeActionListener()
 * @see addActionListener()
 * @see #writeObject
 */
 private void readObject(ObjectInputStream s)
 throws ClassNotFoundException, IOException
 {
 s.defaultReadObject();

 Object keyOrNull;
 while(null != (keyOrNull = s.readObject())) {
 String key = ((String)keyOrNull).intern();

 if (itemListenerK == key)
 addItemListener((ItemListener)(s.readObject()));

 else // skip value for unrecognized key
 s.readObject();
 }
 }

 /**
 * Initialize JNI field and method IDs
 */
 private static native void initIDs();


/////////////////
// Accessibility support
////////////////

 /**
 * Gets the AccessibleContext associated with this CheckboxMenuItem.
 * For checkbox menu items, the AccessibleContext takes the
 * form of an AccessibleAWTCheckboxMenuItem.
 * A new AccessibleAWTCheckboxMenuItem is created if necessary.
 *
 * @return an AccessibleAWTCheckboxMenuItem that serves as the
 * AccessibleContext of this CheckboxMenuItem
 * @since 1.3
 */
 public AccessibleContext getAccessibleContext() {
 if (accessibleContext == null) {
 accessibleContext = new AccessibleAWTCheckboxMenuItem();
 }
 return accessibleContext;
 }

 /**
 * Inner class of CheckboxMenuItem used to provide default support for
 * accessibility. This class is not meant to be used directly by
 * application developers, but is instead meant only to be
 * subclassed by menu component developers.
 * <p>
 * This class implements accessibility support for the
 * <code>CheckboxMenuItem</code> class. It provides an implementation
 * of the Java Accessibility API appropriate to checkbox menu item
 * user-interface elements.
 * @since 1.3
 */
 protected class AccessibleAWTCheckboxMenuItem extends AccessibleAWTMenuItem
 implements AccessibleAction, AccessibleValue
 {
 /*
 * JDK 1.3 serialVersionUID
 */
 private static final long serialVersionUID = -1122642964303476L;

 /**
 * Get the AccessibleAction associated with this object. In the
 * implementation of the Java Accessibility API for this class,
 * return this object, which is responsible for implementing the
 * AccessibleAction interface on behalf of itself.
 *
 * @return this object
 */
 public AccessibleAction getAccessibleAction() {
 return this;
 }

 /**
 * Get the AccessibleValue associated with this object. In the
 * implementation of the Java Accessibility API for this class,
 * return this object, which is responsible for implementing the
 * AccessibleValue interface on behalf of itself.
 *
 * @return this object
 */
 public AccessibleValue getAccessibleValue() {
 return this;
 }

 /**
 * Returns the number of Actions available in this object.
 * If there is more than one, the first one is the "default"
 * action.
 *
 * @return the number of Actions in this object
 */
 public int getAccessibleActionCount() {
 return 0; // To be fully implemented in a future release
 }

 /**
 * Return a description of the specified action of the object.
 *
 * @param i zero-based index of the actions
 */
 public String getAccessibleActionDescription(int i) {
 return null; // To be fully implemented in a future release
 }

 /**
 * Perform the specified Action on the object
 *
 * @param i zero-based index of actions
 * @return true if the action was performed; otherwise false.
 */
 public boolean doAccessibleAction(int i) {
 return false; // To be fully implemented in a future release
 }

 /**
 * Get the value of this object as a Number. If the value has not been
 * set, the return value will be null.
 *
 * @return value of the object
 * @see #setCurrentAccessibleValue
 */
 public Number getCurrentAccessibleValue() {
 return null; // To be fully implemented in a future release
 }

 /**
 * Set the value of this object as a Number.
 *
 * @return true if the value was set; otherwise false
 * @see #getCurrentAccessibleValue
 */
 public boolean setCurrentAccessibleValue(Number n) {
 return false; // To be fully implemented in a future release
 }

 /**
 * Get the minimum value of this object as a Number.
 *
 * @return Minimum value of the object; null if this object does not
 * have a minimum value
 * @see #getMaximumAccessibleValue
 */
 public Number getMinimumAccessibleValue() {
 return null; // To be fully implemented in a future release
 }

 /**
 * Get the maximum value of this object as a Number.
 *
 * @return Maximum value of the object; null if this object does not
 * have a maximum value
 * @see #getMinimumAccessibleValue
 */
 public Number getMaximumAccessibleValue() {
 return null; // To be fully implemented in a future release
 }

 /**
 * Get the role of this object.
 *
 * @return an instance of AccessibleRole describing the role of the
 * object
 */
 public AccessibleRole getAccessibleRole() {
 return AccessibleRole.CHECK_BOX;
 }

 } // class AccessibleAWTMenuItem

}