642 lines
21 KiB
642 lines
21 KiB
/*
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* Copyright (c) 1995, 2013, Oracle and/or its affiliates. All rights reserved.
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* ORACLE PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
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*
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*
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*
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*
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*
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*
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*
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*
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*
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*
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*
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*
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*
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*
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*
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*
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*
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*
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*
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*/
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package java.awt;
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import java.awt.peer.CheckboxMenuItemPeer;
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import java.awt.event.*;
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import java.util.EventListener;
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import java.io.ObjectOutputStream;
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import java.io.ObjectInputStream;
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import java.io.IOException;
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import javax.accessibility.*;
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import sun.awt.AWTAccessor;
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/**
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* This class represents a check box that can be included in a menu.
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* Selecting the check box in the menu changes its state from
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* "on" to "off" or from "off" to "on."
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* <p>
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* The following picture depicts a menu which contains an instance
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* of <code>CheckBoxMenuItem</code>:
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* <p>
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* <img src="doc-files/MenuBar-1.gif"
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* alt="Menu labeled Examples, containing items Basic, Simple, Check, and More Examples. The Check item is a CheckBoxMenuItem instance, in the off state."
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* style="float:center; margin: 7px 10px;">
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* <p>
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* The item labeled <code>Check</code> shows a check box menu item
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* in its "off" state.
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* <p>
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* When a check box menu item is selected, AWT sends an item event to
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* the item. Since the event is an instance of <code>ItemEvent</code>,
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* the <code>processEvent</code> method examines the event and passes
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* it along to <code>processItemEvent</code>. The latter method redirects
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* the event to any <code>ItemListener</code> objects that have
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* registered an interest in item events generated by this menu item.
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*
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* @author Sami Shaio
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* @see java.awt.event.ItemEvent
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* @see java.awt.event.ItemListener
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* @since JDK1.0
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*/
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public class CheckboxMenuItem extends MenuItem implements ItemSelectable, Accessible {
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static {
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/* ensure that the necessary native libraries are loaded */
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Toolkit.loadLibraries();
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if (!GraphicsEnvironment.isHeadless()) {
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initIDs();
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}
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AWTAccessor.setCheckboxMenuItemAccessor(
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new AWTAccessor.CheckboxMenuItemAccessor() {
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public boolean getState(CheckboxMenuItem cmi) {
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return cmi.state;
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}
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});
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}
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/**
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* The state of a checkbox menu item
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* @serial
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* @see #getState()
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* @see #setState(boolean)
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*/
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boolean state = false;
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transient ItemListener itemListener;
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private static final String base = "chkmenuitem";
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private static int nameCounter = 0;
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/*
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* JDK 1.1 serialVersionUID
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*/
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private static final long serialVersionUID = 6190621106981774043L;
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/**
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* Create a check box menu item with an empty label.
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* The item's state is initially set to "off."
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* @exception HeadlessException if GraphicsEnvironment.isHeadless()
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* returns true
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* @see java.awt.GraphicsEnvironment#isHeadless
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* @since JDK1.1
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*/
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public CheckboxMenuItem() throws HeadlessException {
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this("", false);
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}
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/**
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* Create a check box menu item with the specified label.
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* The item's state is initially set to "off."
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* @param label a string label for the check box menu item,
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* or <code>null</code> for an unlabeled menu item.
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* @exception HeadlessException if GraphicsEnvironment.isHeadless()
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* returns true
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* @see java.awt.GraphicsEnvironment#isHeadless
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*/
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public CheckboxMenuItem(String label) throws HeadlessException {
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this(label, false);
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}
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/**
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* Create a check box menu item with the specified label and state.
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* @param label a string label for the check box menu item,
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* or <code>null</code> for an unlabeled menu item.
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* @param state the initial state of the menu item, where
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* <code>true</code> indicates "on" and
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* <code>false</code> indicates "off."
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* @exception HeadlessException if GraphicsEnvironment.isHeadless()
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* returns true
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* @see java.awt.GraphicsEnvironment#isHeadless
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* @since JDK1.1
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*/
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public CheckboxMenuItem(String label, boolean state)
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throws HeadlessException {
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super(label);
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this.state = state;
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}
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/**
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* Construct a name for this MenuComponent. Called by getName() when
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* the name is null.
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*/
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String constructComponentName() {
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synchronized (CheckboxMenuItem.class) {
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return base + nameCounter++;
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}
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}
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/**
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* Creates the peer of the checkbox item. This peer allows us to
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* change the look of the checkbox item without changing its
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* functionality.
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* Most applications do not call this method directly.
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* @see java.awt.Toolkit#createCheckboxMenuItem(java.awt.CheckboxMenuItem)
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* @see java.awt.Component#getToolkit()
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*/
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public void addNotify() {
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synchronized (getTreeLock()) {
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if (peer == null)
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peer = Toolkit.getDefaultToolkit().createCheckboxMenuItem(this);
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super.addNotify();
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}
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}
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/**
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* Determines whether the state of this check box menu item
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* is "on" or "off."
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*
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* @return the state of this check box menu item, where
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* <code>true</code> indicates "on" and
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* <code>false</code> indicates "off"
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* @see #setState
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*/
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public boolean getState() {
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return state;
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}
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/**
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* Sets this check box menu item to the specified state.
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* The boolean value <code>true</code> indicates "on" while
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* <code>false</code> indicates "off."
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*
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* <p>Note that this method should be primarily used to
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* initialize the state of the check box menu item.
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* Programmatically setting the state of the check box
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* menu item will <i>not</i> trigger
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* an <code>ItemEvent</code>. The only way to trigger an
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* <code>ItemEvent</code> is by user interaction.
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*
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* @param b <code>true</code> if the check box
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* menu item is on, otherwise <code>false</code>
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* @see #getState
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*/
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public synchronized void setState(boolean b) {
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state = b;
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CheckboxMenuItemPeer peer = (CheckboxMenuItemPeer)this.peer;
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if (peer != null) {
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peer.setState(b);
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}
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}
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/**
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* Returns the an array (length 1) containing the checkbox menu item
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* label or null if the checkbox is not selected.
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* @see ItemSelectable
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*/
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public synchronized Object[] getSelectedObjects() {
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if (state) {
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Object[] items = new Object[1];
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items[0] = label;
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return items;
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}
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return null;
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}
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/**
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* Adds the specified item listener to receive item events from
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* this check box menu item. Item events are sent in response to user
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* actions, but not in response to calls to setState().
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* If l is null, no exception is thrown and no action is performed.
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* <p>Refer to <a href="doc-files/AWTThreadIssues.html#ListenersThreads"
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* >AWT Threading Issues</a> for details on AWT's threading model.
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*
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* @param l the item listener
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* @see #removeItemListener
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* @see #getItemListeners
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* @see #setState
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* @see java.awt.event.ItemEvent
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* @see java.awt.event.ItemListener
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* @since JDK1.1
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*/
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public synchronized void addItemListener(ItemListener l) {
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if (l == null) {
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return;
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}
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itemListener = AWTEventMulticaster.add(itemListener, l);
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newEventsOnly = true;
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}
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/**
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* Removes the specified item listener so that it no longer receives
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* item events from this check box menu item.
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* If l is null, no exception is thrown and no action is performed.
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* <p>Refer to <a href="doc-files/AWTThreadIssues.html#ListenersThreads"
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* >AWT Threading Issues</a> for details on AWT's threading model.
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*
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* @param l the item listener
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* @see #addItemListener
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* @see #getItemListeners
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* @see java.awt.event.ItemEvent
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* @see java.awt.event.ItemListener
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* @since JDK1.1
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*/
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public synchronized void removeItemListener(ItemListener l) {
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if (l == null) {
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return;
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}
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itemListener = AWTEventMulticaster.remove(itemListener, l);
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}
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/**
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* Returns an array of all the item listeners
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* registered on this checkbox menuitem.
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*
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* @return all of this checkbox menuitem's <code>ItemListener</code>s
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* or an empty array if no item
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* listeners are currently registered
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*
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* @see #addItemListener
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* @see #removeItemListener
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* @see java.awt.event.ItemEvent
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* @see java.awt.event.ItemListener
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* @since 1.4
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*/
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public synchronized ItemListener[] getItemListeners() {
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return getListeners(ItemListener.class);
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}
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/**
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* Returns an array of all the objects currently registered
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* as <code><em>Foo</em>Listener</code>s
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* upon this <code>CheckboxMenuItem</code>.
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* <code><em>Foo</em>Listener</code>s are registered using the
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* <code>add<em>Foo</em>Listener</code> method.
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*
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* <p>
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* You can specify the <code>listenerType</code> argument
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* with a class literal, such as
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* <code><em>Foo</em>Listener.class</code>.
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* For example, you can query a
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* <code>CheckboxMenuItem</code> <code>c</code>
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* for its item listeners with the following code:
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*
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* <pre>ItemListener[] ils = (ItemListener[])(c.getListeners(ItemListener.class));</pre>
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*
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* If no such listeners exist, this method returns an empty array.
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*
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* @param listenerType the type of listeners requested; this parameter
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* should specify an interface that descends from
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* <code>java.util.EventListener</code>
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* @return an array of all objects registered as
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* <code><em>Foo</em>Listener</code>s on this checkbox menuitem,
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* or an empty array if no such
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* listeners have been added
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* @exception ClassCastException if <code>listenerType</code>
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* doesn't specify a class or interface that implements
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* <code>java.util.EventListener</code>
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*
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* @see #getItemListeners
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* @since 1.3
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*/
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public <T extends EventListener> T[] getListeners(Class<T> listenerType) {
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EventListener l = null;
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if (listenerType == ItemListener.class) {
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l = itemListener;
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} else {
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return super.getListeners(listenerType);
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}
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return AWTEventMulticaster.getListeners(l, listenerType);
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}
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// REMIND: remove when filtering is done at lower level
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boolean eventEnabled(AWTEvent e) {
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if (e.id == ItemEvent.ITEM_STATE_CHANGED) {
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if ((eventMask & AWTEvent.ITEM_EVENT_MASK) != 0 ||
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itemListener != null) {
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return true;
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}
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return false;
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}
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return super.eventEnabled(e);
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}
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/**
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* Processes events on this check box menu item.
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* If the event is an instance of <code>ItemEvent</code>,
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* this method invokes the <code>processItemEvent</code> method.
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* If the event is not an item event,
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* it invokes <code>processEvent</code> on the superclass.
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* <p>
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* Check box menu items currently support only item events.
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* <p>Note that if the event parameter is <code>null</code>
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* the behavior is unspecified and may result in an
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* exception.
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*
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* @param e the event
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* @see java.awt.event.ItemEvent
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* @see #processItemEvent
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* @since JDK1.1
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*/
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protected void processEvent(AWTEvent e) {
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if (e instanceof ItemEvent) {
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processItemEvent((ItemEvent)e);
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return;
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}
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super.processEvent(e);
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}
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/**
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* Processes item events occurring on this check box menu item by
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* dispatching them to any registered <code>ItemListener</code> objects.
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* <p>
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* This method is not called unless item events are
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* enabled for this menu item. Item events are enabled
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* when one of the following occurs:
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* <ul>
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* <li>An <code>ItemListener</code> object is registered
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* via <code>addItemListener</code>.
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* <li>Item events are enabled via <code>enableEvents</code>.
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* </ul>
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* <p>Note that if the event parameter is <code>null</code>
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* the behavior is unspecified and may result in an
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* exception.
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*
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* @param e the item event
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* @see java.awt.event.ItemEvent
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* @see java.awt.event.ItemListener
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* @see #addItemListener
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* @see java.awt.MenuItem#enableEvents
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* @since JDK1.1
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*/
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protected void processItemEvent(ItemEvent e) {
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ItemListener listener = itemListener;
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if (listener != null) {
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listener.itemStateChanged(e);
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}
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}
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/*
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* Post an ItemEvent and toggle state.
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*/
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void doMenuEvent(long when, int modifiers) {
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setState(!state);
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Toolkit.getEventQueue().postEvent(
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new ItemEvent(this, ItemEvent.ITEM_STATE_CHANGED,
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getLabel(),
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state ? ItemEvent.SELECTED :
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ItemEvent.DESELECTED));
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}
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/**
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* Returns a string representing the state of this
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* <code>CheckBoxMenuItem</code>. This
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* method is intended to be used only for debugging purposes, and the
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* content and format of the returned string may vary between
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* implementations. The returned string may be empty but may not be
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* <code>null</code>.
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*
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* @return the parameter string of this check box menu item
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*/
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public String paramString() {
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return super.paramString() + ",state=" + state;
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}
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/* Serialization support.
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*/
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/*
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* Serial Data Version
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* @serial
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*/
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private int checkboxMenuItemSerializedDataVersion = 1;
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/**
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* Writes default serializable fields to stream. Writes
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* a list of serializable <code>ItemListeners</code>
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* as optional data. The non-serializable
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* <code>ItemListeners</code> are detected and
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* no attempt is made to serialize them.
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*
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* @param s the <code>ObjectOutputStream</code> to write
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* @serialData <code>null</code> terminated sequence of
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* 0 or more pairs; the pair consists of a <code>String</code>
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* and an <code>Object</code>; the <code>String</code> indicates
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* the type of object and is one of the following:
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* <code>itemListenerK</code> indicating an
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* <code>ItemListener</code> object
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*
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* @see AWTEventMulticaster#save(ObjectOutputStream, String, EventListener)
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* @see java.awt.Component#itemListenerK
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* @see #readObject(ObjectInputStream)
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*/
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private void writeObject(ObjectOutputStream s)
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throws java.io.IOException
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{
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s.defaultWriteObject();
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AWTEventMulticaster.save(s, itemListenerK, itemListener);
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s.writeObject(null);
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}
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/*
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* Reads the <code>ObjectInputStream</code> and if it
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* isn't <code>null</code> adds a listener to receive
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* item events fired by the <code>Checkbox</code> menu item.
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* Unrecognized keys or values will be ignored.
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*
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* @param s the <code>ObjectInputStream</code> to read
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* @serial
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* @see removeActionListener()
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* @see addActionListener()
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* @see #writeObject
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*/
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private void readObject(ObjectInputStream s)
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throws ClassNotFoundException, IOException
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{
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s.defaultReadObject();
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Object keyOrNull;
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while(null != (keyOrNull = s.readObject())) {
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String key = ((String)keyOrNull).intern();
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if (itemListenerK == key)
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addItemListener((ItemListener)(s.readObject()));
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else // skip value for unrecognized key
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s.readObject();
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}
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}
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/**
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* Initialize JNI field and method IDs
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*/
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private static native void initIDs();
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/////////////////
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// Accessibility support
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////////////////
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/**
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* Gets the AccessibleContext associated with this CheckboxMenuItem.
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* For checkbox menu items, the AccessibleContext takes the
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* form of an AccessibleAWTCheckboxMenuItem.
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* A new AccessibleAWTCheckboxMenuItem is created if necessary.
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*
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* @return an AccessibleAWTCheckboxMenuItem that serves as the
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* AccessibleContext of this CheckboxMenuItem
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* @since 1.3
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*/
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public AccessibleContext getAccessibleContext() {
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if (accessibleContext == null) {
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accessibleContext = new AccessibleAWTCheckboxMenuItem();
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}
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return accessibleContext;
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}
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/**
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* Inner class of CheckboxMenuItem used to provide default support for
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* accessibility. This class is not meant to be used directly by
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* application developers, but is instead meant only to be
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* subclassed by menu component developers.
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* <p>
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* This class implements accessibility support for the
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* <code>CheckboxMenuItem</code> class. It provides an implementation
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* of the Java Accessibility API appropriate to checkbox menu item
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* user-interface elements.
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* @since 1.3
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*/
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protected class AccessibleAWTCheckboxMenuItem extends AccessibleAWTMenuItem
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implements AccessibleAction, AccessibleValue
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{
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/*
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* JDK 1.3 serialVersionUID
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*/
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private static final long serialVersionUID = -1122642964303476L;
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/**
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* Get the AccessibleAction associated with this object. In the
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* implementation of the Java Accessibility API for this class,
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* return this object, which is responsible for implementing the
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* AccessibleAction interface on behalf of itself.
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*
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* @return this object
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*/
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public AccessibleAction getAccessibleAction() {
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return this;
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}
|
|
|
|
/**
|
|
* 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
|
|
|
|
}
|