/*
* @(#)PopupMenu.java 1.29 04/03/16
*
* Copyright 2004 Sun Microsystems, Inc. All rights reserved.
* SUN PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
*/
package java.awt;
import java.awt.peer.PopupMenuPeer;
import javax.accessibility.*;
/**
* A class that implements a menu which can be dynamically popped up
* at a specified position within a component.
* <p>
* As the inheritance hierarchy implies, a <code>PopupMenu</code>
* can be used anywhere a <code>Menu</code> can be used.
* However, if you use a <code>PopupMenu</code> like a <code>Menu</code>
* (e.g., you add it to a <code>MenuBar</code>), then you <b>cannot</b>
* call <code>show</code> on that <code>PopupMenu</code>.
*
* @version 1.29 03/16/04
* @author Amy Fowler
*/
public class PopupMenu extends Menu {
private static final String base = "popup";
static int nameCounter = 0;
/*
* JDK 1.1 serialVersionUID
*/
private static final long serialVersionUID = -4620452533522760060L;
/**
* Creates a new popup menu with an empty name.
* @exception HeadlessException if GraphicsEnvironment.isHeadless()
* returns true.
* @see java.awt.GraphicsEnvironment#isHeadless
*/
public PopupMenu() throws HeadlessException {
this("");
}
/**
* Creates a new popup menu with the specified name.
*
* @param label a non-<code>null</code> string specifying
* the popup menu's label
* @exception HeadlessException if GraphicsEnvironment.isHeadless()
* returns true.
* @see java.awt.GraphicsEnvironment#isHeadless
*/
public PopupMenu(String label) throws HeadlessException {
super(label);
}
/**
* Constructs a name for this <code>MenuComponent</code>.
* Called by <code>getName</code> when the name is <code>null</code>.
*/
String constructComponentName() {
synchronized (getClass()) {
return base + nameCounter++;
}
}
/**
* Creates the popup menu's peer.
* The peer allows us to change the appearance of the popup menu without
* changing any of the popup menu's functionality.
*/
public void addNotify() {
synchronized (getTreeLock()) {
// If our parent is not a Component, then this PopupMenu is
// really just a plain, old Menu.
if (parent != null && !(parent instanceof Component)) {
super.addNotify();
}
else {
if (peer == null)
peer = Toolkit.getDefaultToolkit().createPopupMenu(this);
int nitems = getItemCount();
for (int i = 0 ; i < nitems ; i++) {
MenuItem mi = getItem(i);
mi.parent = this;
mi.addNotify();
}
}
}
}
/**
* Shows the popup menu at the x, y position relative to an origin
* component.
* The origin component must be contained within the component
* hierarchy of the popup menu's parent. Both the origin and the parent
* must be showing on the screen for this method to be valid.
* <p>
* If this <code>PopupMenu</code> is being used as a <code>Menu</code>
* (i.e., it has a non-<code>Component</code> parent),
* then you cannot call this method on the <code>PopupMenu</code>.
*
* @param origin the component which defines the coordinate space
* @param x the x coordinate position to popup the menu
* @param y the y coordinate position to popup the menu
* @exception NullPointerException if the parent is <code>null</code>
* @exception IllegalArgumentException if this <code>PopupMenu</code>
* has a non-<code>Component</code> parent
* @exception IllegalArgumentException if the origin is not in the
* parent's heirarchy
* @exception RuntimeException if the parent is not showing on screen
*/
public void show(Component origin, int x, int y) {
// Use localParent for thread safety.
MenuContainer localParent = parent;
if (localParent == null) {
throw new NullPointerException("parent is null");
}
if (!(localParent instanceof Component)) {
throw new IllegalArgumentException(
"PopupMenus with non-Component parents cannot be shown");
}
Component compParent = (Component)localParent;
if (compParent != origin &&
compParent instanceof Container &&
!((Container)compParent).isAncestorOf(origin)) {
throw new IllegalArgumentException(
"origin not in parent's hierarchy");
}
if (compParent.getPeer() == null || !compParent.isShowing()) {
throw new RuntimeException("parent not showing on screen");
}
if (peer == null) {
addNotify();
}
synchronized (getTreeLock()) {
if (peer != null) {
((PopupMenuPeer)peer).show(
new Event(origin, 0, Event.MOUSE_DOWN, x, y, 0, 0));
}
}
}
/////////////////
// Accessibility support
////////////////
/**
* Gets the <code>AccessibleContext</code> associated with this
* <code>PopupMenu</code>.
*
* @return the <code>AccessibleContext</code> of this
* <code>PopupMenu</code>
*/
public AccessibleContext getAccessibleContext() {
if (accessibleContext == null) {
accessibleContext = new AccessibleAWTPopupMenu();
}
return accessibleContext;
}
/**
* Inner class of PopupMenu 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>
* The class used to obtain the accessible role for this object.
*/
protected class AccessibleAWTPopupMenu extends AccessibleAWTMenu
{
/*
* JDK 1.3 serialVersionUID
*/
private static final long serialVersionUID = -4282044795947239955L;
/**
* Get the role of this object.
*
* @return an instance of AccessibleRole describing the role of the
* object
*/
public AccessibleRole getAccessibleRole() {
return AccessibleRole.POPUP_MENU;
}
} // class AccessibleAWTPopupMenu
}
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