Component to the user, typically
* on top of all the other Components in a particular containment
* hierarchy. Popups have a very small life cycle. Once you
* have obtained a Popup, and hidden it (invoked the
* hide method), you should no longer
* invoke any methods on it. This allows the PopupFactory to cache
* Popups for later use.
*
* The general contract is that if you need to change the size of the
* Component, or location of the Popup, you should
* obtain a new Popup.
*
* Popup does not descend from Component, rather
* implementations of Popup are responsible for creating
* and maintaining their own Components to render the
* requested Component to the user.
*
* You typically do not explicitly create an instance of Popup,
* instead obtain one from a PopupFactory.
*
* @see PopupFactory
*
* @since 1.4
*/
public class Popup {
/**
* The Component representing the Popup.
*/
private Component component;
/**
* Creates a Popup for the Component owner
* containing the Component contents. owner
* is used to determine which Window the new
* Popup will parent the Component the
* Popup creates to.
* A null owner implies there is no valid parent.
* x and
* y specify the preferred initial location to place
* the Popup at. Based on screen size, or other paramaters,
* the Popup may not display at x and
* y.
*
* @param owner Component mouse coordinates are relative to, may be null
* @param contents Contents of the Popup
* @param x Initial x screen coordinate
* @param y Initial y screen coordinate
* @exception IllegalArgumentException if contents is null
*/
protected Popup(Component owner, Component contents, int x, int y) {
this();
if (contents == null) {
throw new IllegalArgumentException("Contents must be non-null");
}
reset(owner, contents, x, y);
}
/**
* Creates a Popup. This is provided for subclasses.
*/
protected Popup() {
}
/**
* Makes the Popup visible. If the Popup is
* currently visible, this has no effect.
*/
@SuppressWarnings("deprecation")
public void show() {
Component component = getComponent();
if (component != null) {
component.show();
}
}
/**
* Hides and disposes of the Popup. Once a Popup
* has been disposed you should no longer invoke methods on it. A
* disposed Popup may be reclaimed and later used
* based on the PopupFactory. As such, if you invoke methods
* on a disposed Popup, indeterminate
* behavior will result.
*/
@SuppressWarnings("deprecation")
public void hide() {
Component component = getComponent();
if (component instanceof JWindow) {
component.hide();
((JWindow)component).getContentPane().removeAll();
}
dispose();
}
/**
* Frees any resources the Popup may be holding onto.
*/
void dispose() {
Component component = getComponent();
Window window = SwingUtilities.getWindowAncestor(component);
if (component instanceof JWindow) {
((Window)component).dispose();
component = null;
}
// If our parent is a DefaultFrame, we need to dispose it, too.
if (window instanceof DefaultFrame) {
window.dispose();
}
}
/**
* Resets the Popup to an initial state.
*/
void reset(Component owner, Component contents, int ownerX, int ownerY) {
if (getComponent() == null) {
component = createComponent(owner);
}
Component c = getComponent();
if (c instanceof JWindow) {
JWindow component = (JWindow)getComponent();
// Sets the proper location, and resets internal state of the window
component.setBounds(ownerX, ownerY, 1, 1);
component.getContentPane().add(contents, BorderLayout.CENTER);
component.invalidate();
component.validate();
if(component.isVisible()) {
// Do not call pack() if window is not visible to
// avoid early native peer creation
pack();
}
}
}
/**
* Causes the Popup to be sized to fit the preferred size
* of the Component it contains.
*/
void pack() {
Component component = getComponent();
if (component instanceof Window) {
((Window)component).pack();
}
}
/**
* Returns the Window to use as the parent of the
* Window created for the Popup. This creates
* a new DefaultFrame, if necessary.
*/
private Window getParentWindow(Component owner) {
Window window = null;
if (owner instanceof Window) {
window = (Window)owner;
}
else if (owner != null) {
window = SwingUtilities.getWindowAncestor(owner);
}
if (window == null) {
window = new DefaultFrame();
}
return window;
}
/**
* Creates the Component to use as the parent of the Popup.
* The default implementation creates a Window, subclasses
* should override.
*/
Component createComponent(Component owner) {
if (GraphicsEnvironment.isHeadless()) {
// Generally not useful, bail.
return null;
}
return new HeavyWeightWindow(getParentWindow(owner));
}
/**
* Returns the Component returned from
* createComponent that will hold the Popup.
*/
Component getComponent() {
return component;
}
/**
* Component used to house window.
*/
@SuppressWarnings("serial") // Superclass is not serializable across versions
static class HeavyWeightWindow extends JWindow implements ModalExclude {
HeavyWeightWindow(Window parent) {
super(parent);
setFocusableWindowState(false);
setType(Window.Type.POPUP);
// Popups are typically transient and most likely won't benefit
// from true double buffering. Turn it off here.
getRootPane().setUseTrueDoubleBuffering(false);
// Try to set "always-on-top" for the popup window.
// Applets usually don't have sufficient permissions to do it.
// In this case simply ignore the exception.
try {
setAlwaysOnTop(true);
} catch (SecurityException se) {
// setAlwaysOnTop is restricted,
// the exception is ignored
}
}
public void update(Graphics g) {
paint(g);
}
@SuppressWarnings("deprecation")
public void show() {
this.pack();
if (getWidth() > 0 && getHeight() > 0) {
super.show();
}
}
}
/**
* Used if no valid Window ancestor of the supplied owner is found.
*
* PopupFactory uses this as a way to know when the Popup shouldn't * be cached based on the Window. */ @SuppressWarnings("serial") // JDK-implementation class static class DefaultFrame extends Frame { } }