JDK14/Java14源码在线阅读
/*
* Copyright (c) 1999, 2018, Oracle and/or its affiliates. All rights reserved.
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
*
* This code is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License version 2 only, as
* published by the Free Software Foundation. Oracle designates this
* particular file as subject to the "Classpath" exception as provided
* by Oracle in the LICENSE file that accompanied this code.
*
* This code is distributed in the hope that it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
* version 2 for more details (a copy is included in the LICENSE file that
* accompanied this code).
*
* You should have received a copy of the GNU General Public License version
* 2 along with this work; if not, write to the Free Software Foundation,
* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
*
* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
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package javax.swing;
import sun.awt.EmbeddedFrame;
import sun.awt.OSInfo;
import sun.swing.SwingAccessor;
import java.applet.Applet;
import java.awt.*;
import java.awt.event.WindowAdapter;
import java.awt.event.WindowEvent;
import java.security.AccessController;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import static javax.swing.ClientPropertyKey.PopupFactory_FORCE_HEAVYWEIGHT_POPUP;
/**
* <code>PopupFactory</code>, as the name implies, is used to obtain
* instances of <code>Popup</code>s. <code>Popup</code>s are used to
* display a <code>Component</code> above all other <code>Component</code>s
* in a particular containment hierarchy. The general contract is that
* once you have obtained a <code>Popup</code> from a
* <code>PopupFactory</code>, you must invoke <code>hide</code> on the
* <code>Popup</code>. The typical usage is:
* <pre>
* PopupFactory factory = PopupFactory.getSharedInstance();
* Popup popup = factory.getPopup(owner, contents, x, y);
* popup.show();
* ...
* popup.hide();
* </pre>
*
* @see Popup
*
* @since 1.4
*/
public class PopupFactory {
static {
SwingAccessor.setPopupFactoryAccessor(new SwingAccessor.PopupFactoryAccessor() {
@Override
public Popup getHeavyWeightPopup(PopupFactory factory, Component owner,
Component contents, int ownerX, int ownerY) {
return factory.getPopup(owner, contents, ownerX, ownerY, HEAVY_WEIGHT_POPUP);
}
});
}
/**
* The shared instanceof <code>PopupFactory</code> is per
* <code>AppContext</code>. This is the key used in the
* <code>AppContext</code> to locate the <code>PopupFactory</code>.
*/
private static final Object SharedInstanceKey =
new StringBuffer("PopupFactory.SharedInstanceKey");
/**
* Max number of items to store in any one particular cache.
*/
private static final int MAX_CACHE_SIZE = 5;
/**
* Key used to indicate a light weight popup should be used.
*/
static final int LIGHT_WEIGHT_POPUP = 0;
/**
* Key used to indicate a medium weight Popup should be used.
*/
static final int MEDIUM_WEIGHT_POPUP = 1;
/*
* Key used to indicate a heavy weight Popup should be used.
*/
static final int HEAVY_WEIGHT_POPUP = 2;
/**
* Default type of Popup to create.
*/
private int popupType = LIGHT_WEIGHT_POPUP;
/**
* Sets the <code>PopupFactory</code> that will be used to obtain
* <code>Popup</code>s.
* This will throw an <code>IllegalArgumentException</code> if
* <code>factory</code> is null.
*
* @param factory Shared PopupFactory
* @exception IllegalArgumentException if <code>factory</code> is null
* @see #getPopup
*/
public static void setSharedInstance(PopupFactory factory) {
if (factory == null) {
throw new IllegalArgumentException("PopupFactory can not be null");
}
SwingUtilities.appContextPut(SharedInstanceKey, factory);
}
/**
* Returns the shared <code>PopupFactory</code> which can be used
* to obtain <code>Popup</code>s.
*
* @return Shared PopupFactory
*/
public static PopupFactory getSharedInstance() {
PopupFactory factory = (PopupFactory)SwingUtilities.appContextGet(
SharedInstanceKey);
if (factory == null) {
factory = new PopupFactory();
setSharedInstance(factory);
}
return factory;
}
/**
* Provides a hint as to the type of <code>Popup</code> that should
* be created.
*/
void setPopupType(int type) {
popupType = type;
}
/**
* Returns the preferred type of Popup to create.
*/
int getPopupType() {
return popupType;
}
/**
* Creates a <code>Popup</code> for the Component <code>owner</code>
* containing the Component <code>contents</code>. <code>owner</code>
* is used to determine which <code>Window</code> the new
* <code>Popup</code> will parent the <code>Component</code> the
* <code>Popup</code> creates to. A null <code>owner</code> implies there
* is no valid parent. <code>x</code> and
* <code>y</code> specify the preferred initial location to place
* the <code>Popup</code> at. Based on screen size, or other paramaters,
* the <code>Popup</code> may not display at <code>x</code> and
* <code>y</code>.
*
* @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
* @return Popup containing Contents
*/
public Popup getPopup(Component owner, Component contents,
int x, int y) throws IllegalArgumentException {
return getPopup(owner, contents, x, y, false);
}
/**
* Creates a {@code Popup} for the Component {@code owner}
* containing the Component {@code contents}.
* The window containing the component {@code owner}
* will be used as the parent window. A null {@code owner} implies there
* is no valid parent. {@code x} and {@code y} specify the preferred
* initial location to place the {@code Popup} at. Based on screen size,
* or other parameters, the {@code Popup} may not display at {@code x} and
* {@code y}. {@code isHeavyWeightPopup} specifies if the {@code Popup}
* will be heavyweight. Passing {@code true} will force the {@code Popup}
* type to be heavyweight, otherwise {@code Popup} type will be selected by
* {@code Popup} factory. Lightweight {@code Popup} windows are more
* efficient than heavyweight (native peer) windows, but lightweight
* and heavyweight components do not mix well in a GUI.
* This method is intended to be used only by PopupFactory sub-classes.
* @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
* @param isHeavyWeightPopup true if Popup should be heavy weight,
* otherwise popup type will be selected by popup factory.
* @throws IllegalArgumentException if contents is null
* @return Popup containing Contents
*/
protected Popup getPopup(Component owner, Component contents, int x, int y,
boolean isHeavyWeightPopup) throws IllegalArgumentException {
if (contents == null) {
throw new IllegalArgumentException(
"Popup.getPopup must be passed non-null contents");
}
if (isHeavyWeightPopup) {
return getPopup(owner, contents, x, y, HEAVY_WEIGHT_POPUP);
}
int popupType = getPopupType(owner, contents, x, y);
Popup popup = getPopup(owner, contents, x, y, popupType);
if (popup == null) {
// Didn't fit, force to heavy.
popup = getPopup(owner, contents, x, y, HEAVY_WEIGHT_POPUP);
}
return popup;
}
/**
* Returns the popup type to use for the specified parameters.
*/
private int getPopupType(Component owner, Component contents,
int ownerX, int ownerY) {
int popupType = getPopupType();
if (owner == null || invokerInHeavyWeightPopup(owner)) {
popupType = HEAVY_WEIGHT_POPUP;
}
else if (popupType == LIGHT_WEIGHT_POPUP &&
!(contents instanceof JToolTip) &&
!(contents instanceof JPopupMenu)) {
popupType = MEDIUM_WEIGHT_POPUP;
}
// Check if the parent component is an option pane. If so we need to
// force a heavy weight popup in order to have event dispatching work
// correctly.
Component c = owner;
while (c != null) {
if (c instanceof JComponent) {
if (((JComponent)c).getClientProperty(
PopupFactory_FORCE_HEAVYWEIGHT_POPUP) == Boolean.TRUE) {
popupType = HEAVY_WEIGHT_POPUP;
break;
}
}
c = c.getParent();
}
return popupType;
}
/**
* Obtains the appropriate <code>Popup</code> based on
* <code>popupType</code>.
*/
@SuppressWarnings("deprecation")
private Popup getPopup(Component owner, Component contents,
int ownerX, int ownerY, int popupType) {
if (GraphicsEnvironment.isHeadless()) {
return getHeadlessPopup(owner, contents, ownerX, ownerY);
}
switch(popupType) {
case LIGHT_WEIGHT_POPUP:
return getLightWeightPopup(owner, contents, ownerX, ownerY);
case MEDIUM_WEIGHT_POPUP:
return getMediumWeightPopup(owner, contents, ownerX, ownerY);
case HEAVY_WEIGHT_POPUP:
Popup popup = getHeavyWeightPopup(owner, contents, ownerX, ownerY);
if ((AccessController.doPrivileged(OSInfo.getOSTypeAction()) ==
OSInfo.OSType.MACOSX) && (owner != null) &&
(EmbeddedFrame.getAppletIfAncestorOf(owner) != null)) {
((HeavyWeightPopup)popup).setCacheEnabled(false);
}
return popup;
}
return null;
}
/**
* Creates a headless popup
*/
private Popup getHeadlessPopup(Component owner, Component contents,
int ownerX, int ownerY) {
return HeadlessPopup.getHeadlessPopup(owner, contents, ownerX, ownerY);
}
/**
* Creates a light weight popup.
*/
private Popup getLightWeightPopup(Component owner, Component contents,
int ownerX, int ownerY) {
return LightWeightPopup.getLightWeightPopup(owner, contents, ownerX,
ownerY);
}
/**
* Creates a medium weight popup.
*/
private Popup getMediumWeightPopup(Component owner, Component contents,
int ownerX, int ownerY) {
return MediumWeightPopup.getMediumWeightPopup(owner, contents,
ownerX, ownerY);
}
/**
* Creates a heavy weight popup.
*/
private Popup getHeavyWeightPopup(Component owner, Component contents,
int ownerX, int ownerY) {
if (GraphicsEnvironment.isHeadless()) {
return getMediumWeightPopup(owner, contents, ownerX, ownerY);
}
return HeavyWeightPopup.getHeavyWeightPopup(owner, contents, ownerX,
ownerY);
}
/**
* Returns true if the Component <code>i</code> inside a heavy weight
* <code>Popup</code>.
*/
private boolean invokerInHeavyWeightPopup(Component i) {
if (i != null) {
Container parent;
for(parent = i.getParent() ; parent != null ; parent =
parent.getParent()) {
if (parent instanceof Popup.HeavyWeightWindow) {
return true;
}
}
}
return false;
}
/**
* Popup implementation that uses a Window as the popup.
*/
private static class HeavyWeightPopup extends Popup {
private static final Object heavyWeightPopupCacheKey =
new StringBuffer("PopupFactory.heavyWeightPopupCache");
private volatile boolean isCacheEnabled = true;
/**
* Returns either a new or recycled <code>Popup</code> containing
* the specified children.
*/
static Popup getHeavyWeightPopup(Component owner, Component contents,
int ownerX, int ownerY) {
Window window = (owner != null) ? SwingUtilities.
getWindowAncestor(owner) : null;
HeavyWeightPopup popup = null;
if (window != null) {
popup = getRecycledHeavyWeightPopup(window);
}
boolean focusPopup = false;
if(contents != null && contents.isFocusable()) {
if(contents instanceof JPopupMenu) {
JPopupMenu jpm = (JPopupMenu) contents;
Component[] popComps = jpm.getComponents();
for (Component popComp : popComps) {
if (!(popComp instanceof MenuElement) &&
!(popComp instanceof JSeparator)) {
focusPopup = true;
break;
}
}
}
}
if (popup == null ||
((JWindow) popup.getComponent())
.getFocusableWindowState() != focusPopup) {
if(popup != null) {
// The recycled popup can't serve us well
// dispose it and create new one
popup._dispose();
}
popup = new HeavyWeightPopup();
}
popup.reset(owner, contents, ownerX, ownerY);
if(focusPopup) {
JWindow wnd = (JWindow) popup.getComponent();
wnd.setFocusableWindowState(true);
// Set window name. We need this in BasicPopupMenuUI
// to identify focusable popup window.
wnd.setName("###focusableSwingPopup###");
}
return popup;
}
/**
* Returns a previously disposed heavy weight <code>Popup</code>
* associated with <code>window</code>. This will return null if
* there is no <code>HeavyWeightPopup</code> associated with
* <code>window</code>.
*/
private static HeavyWeightPopup getRecycledHeavyWeightPopup(Window w) {
synchronized (HeavyWeightPopup.class) {
List<HeavyWeightPopup> cache;
Map<Window, List<HeavyWeightPopup>> heavyPopupCache = getHeavyWeightPopupCache();
if (heavyPopupCache.containsKey(w)) {
cache = heavyPopupCache.get(w);
} else {
return null;
}
if (cache.size() > 0) {
HeavyWeightPopup r = cache.get(0);
cache.remove(0);
return r;
}
return null;
}
}
/**
* Returns the cache to use for heavy weight popups. Maps from
* <code>Window</code> to a <code>List</code> of
* <code>HeavyWeightPopup</code>s.
*/
@SuppressWarnings("unchecked")
private static Map<Window, List<HeavyWeightPopup>> getHeavyWeightPopupCache() {
synchronized (HeavyWeightPopup.class) {
Map<Window, List<HeavyWeightPopup>> cache = (Map<Window, List<HeavyWeightPopup>>)SwingUtilities.appContextGet(
heavyWeightPopupCacheKey);
if (cache == null) {
cache = new HashMap<>(2);
SwingUtilities.appContextPut(heavyWeightPopupCacheKey,
cache);
}
return cache;
}
}
/**
* Recycles the passed in <code>HeavyWeightPopup</code>.
*/
private static void recycleHeavyWeightPopup(HeavyWeightPopup popup) {
synchronized (HeavyWeightPopup.class) {
List<HeavyWeightPopup> cache;
Window window = SwingUtilities.getWindowAncestor(
popup.getComponent());
Map<Window, List<HeavyWeightPopup>> heavyPopupCache = getHeavyWeightPopupCache();
if (window instanceof Popup.DefaultFrame ||
!window.isVisible()) {
// If the Window isn't visible, we don't cache it as we
// likely won't ever get a windowClosed event to clean up.
// We also don't cache DefaultFrames as this indicates
// there wasn't a valid Window parent, and thus we don't
// know when to clean up.
popup._dispose();
return;
} else if (heavyPopupCache.containsKey(window)) {
cache = heavyPopupCache.get(window);
} else {
cache = new ArrayList<HeavyWeightPopup>();
heavyPopupCache.put(window, cache);
// Clean up if the Window is closed
final Window w = window;
w.addWindowListener(new WindowAdapter() {
public void windowClosed(WindowEvent e) {
List<HeavyWeightPopup> popups;
synchronized(HeavyWeightPopup.class) {
Map<Window, List<HeavyWeightPopup>> heavyPopupCache2 =
getHeavyWeightPopupCache();
popups = heavyPopupCache2.remove(w);
}
if (popups != null) {
for (int counter = popups.size() - 1;
counter >= 0; counter--) {
popups.get(counter)._dispose();
}
}
}
});
}
if(cache.size() < MAX_CACHE_SIZE) {
cache.add(popup);
} else {
popup._dispose();
}
}
}
/**
* Enables or disables cache for current object.
*/
void setCacheEnabled(boolean enable) {
isCacheEnabled = enable;
}
//
// Popup methods
//
public void hide() {
super.hide();
if (isCacheEnabled) {
recycleHeavyWeightPopup(this);
} else {
this._dispose();
}
}
/**
* As we recycle the <code>Window</code>, we don't want to dispose it,
* thus this method does nothing, instead use <code>_dipose</code>
* which will handle the disposing.
*/
void dispose() {
}
void _dispose() {
super.dispose();
}
}
/**
* ContainerPopup consolidates the common code used in the light/medium
* weight implementations of <code>Popup</code>.
*/
private static class ContainerPopup extends Popup {
/** Component we are to be added to. */
Component owner;
/** Desired x location. */
int x;
/** Desired y location. */
int y;
public void hide() {
Component component = getComponent();
if (component != null) {
Container parent = component.getParent();
if (parent != null) {
Rectangle bounds = component.getBounds();
parent.remove(component);
parent.repaint(bounds.x, bounds.y, bounds.width,
bounds.height);
}
}
owner = null;
}
public void pack() {
Component component = getComponent();
if (component != null) {
component.setSize(component.getPreferredSize());
}
}
void reset(Component owner, Component contents, int ownerX,
int ownerY) {
if ((owner instanceof JFrame) || (owner instanceof JDialog) ||
(owner instanceof JWindow)) {
// Force the content to be added to the layered pane, otherwise
// we'll get an exception when adding to the RootPaneContainer.
owner = ((RootPaneContainer)owner).getLayeredPane();
}
super.reset(owner, contents, ownerX, ownerY);
x = ownerX;
y = ownerY;
this.owner = owner;
}
boolean overlappedByOwnedWindow() {
Component component = getComponent();
if(owner != null && component != null) {
Window w = SwingUtilities.getWindowAncestor(owner);
if (w == null) {
return false;
}
Window[] ownedWindows = w.getOwnedWindows();
if(ownedWindows != null) {
Rectangle bnd = component.getBounds();
for (Window window : ownedWindows) {
if (window.isVisible() &&
bnd.intersects(window.getBounds())) {
return true;
}
}
}
}
return false;
}
/**
* Returns true if popup can fit the screen and the owner's top parent.
* It determines can popup be lightweight or mediumweight.
*/
@SuppressWarnings("deprecation")
boolean fitsOnScreen() {
boolean result = false;
Component component = getComponent();
if (owner != null && component != null) {
int popupWidth = component.getWidth();
int popupHeight = component.getHeight();
Container parent = (Container) SwingUtilities.getRoot(owner);
if (parent instanceof JFrame ||
parent instanceof JDialog ||
parent instanceof JWindow) {
Rectangle parentBounds = parent.getBounds();
Insets i = parent.getInsets();
parentBounds.x += i.left;
parentBounds.y += i.top;
parentBounds.width -= i.left + i.right;
parentBounds.height -= i.top + i.bottom;
if (JPopupMenu.canPopupOverlapTaskBar()) {
GraphicsConfiguration gc =
parent.getGraphicsConfiguration();
Rectangle popupArea = getContainerPopupArea(gc);
result = parentBounds.intersection(popupArea)
.contains(x, y, popupWidth, popupHeight);
} else {
result = parentBounds
.contains(x, y, popupWidth, popupHeight);
}
} else if (parent instanceof JApplet) {
Rectangle parentBounds = parent.getBounds();
Point p = parent.getLocationOnScreen();
parentBounds.x = p.x;
parentBounds.y = p.y;
result = parentBounds.contains(x, y, popupWidth, popupHeight);
}
}
return result;
}
Rectangle getContainerPopupArea(GraphicsConfiguration gc) {
Rectangle screenBounds;
Toolkit toolkit = Toolkit.getDefaultToolkit();
Insets insets;
if(gc != null) {
// If we have GraphicsConfiguration use it
// to get screen bounds
screenBounds = gc.getBounds();
insets = toolkit.getScreenInsets(gc);
} else {
// If we don't have GraphicsConfiguration use primary screen
screenBounds = new Rectangle(toolkit.getScreenSize());
insets = new Insets(0, 0, 0, 0);
}
// Take insets into account
screenBounds.x += insets.left;
screenBounds.y += insets.top;
screenBounds.width -= (insets.left + insets.right);
screenBounds.height -= (insets.top + insets.bottom);
return screenBounds;
}
}
/**
* Popup implementation that is used in headless environment.
*/
private static class HeadlessPopup extends ContainerPopup {
static Popup getHeadlessPopup(Component owner, Component contents,
int ownerX, int ownerY) {
HeadlessPopup popup = new HeadlessPopup();
popup.reset(owner, contents, ownerX, ownerY);
return popup;
}
Component createComponent(Component owner) {
return new Panel(new BorderLayout());
}
public void show() {
}
public void hide() {
}
}
/**
* Popup implementation that uses a JPanel as the popup.
*/
private static class LightWeightPopup extends ContainerPopup {
private static final Object lightWeightPopupCacheKey =
new StringBuffer("PopupFactory.lightPopupCache");
/**
* Returns a light weight <code>Popup</code> implementation. If
* the <code>Popup</code> needs more space that in available in
* <code>owner</code>, this will return null.
*/
static Popup getLightWeightPopup(Component owner, Component contents,
int ownerX, int ownerY) {
LightWeightPopup popup = getRecycledLightWeightPopup();
if (popup == null) {
popup = new LightWeightPopup();
}
popup.reset(owner, contents, ownerX, ownerY);
if (!popup.fitsOnScreen() ||
popup.overlappedByOwnedWindow()) {
popup.hide();
return null;
}
return popup;
}
/**
* Returns the cache to use for heavy weight popups.
*/
@SuppressWarnings("unchecked")
private static List<LightWeightPopup> getLightWeightPopupCache() {
List<LightWeightPopup> cache = (List<LightWeightPopup>)SwingUtilities.appContextGet(
lightWeightPopupCacheKey);
if (cache == null) {
cache = new ArrayList<>();
SwingUtilities.appContextPut(lightWeightPopupCacheKey, cache);
}
return cache;
}
/**
* Recycles the LightWeightPopup <code>popup</code>.
*/
private static void recycleLightWeightPopup(LightWeightPopup popup) {
synchronized (LightWeightPopup.class) {
List<LightWeightPopup> lightPopupCache = getLightWeightPopupCache();
if (lightPopupCache.size() < MAX_CACHE_SIZE) {
lightPopupCache.add(popup);
}
}
}
/**
* Returns a previously used <code>LightWeightPopup</code>, or null
* if none of the popups have been recycled.
*/
private static LightWeightPopup getRecycledLightWeightPopup() {
synchronized (LightWeightPopup.class) {
List<LightWeightPopup> lightPopupCache = getLightWeightPopupCache();
if (lightPopupCache.size() > 0) {
LightWeightPopup r = lightPopupCache.get(0);
lightPopupCache.remove(0);
return r;
}
return null;
}
}
//
// Popup methods
//
public void hide() {
super.hide();
Container component = (Container)getComponent();
component.removeAll();
recycleLightWeightPopup(this);
}
@SuppressWarnings("deprecation")
public void show() {
Container parent = null;
if (owner != null) {
parent = (owner instanceof Container? (Container)owner : owner.getParent());
}
// Try to find a JLayeredPane and Window to add
for (Container p = parent; p != null; p = p.getParent()) {
if (p instanceof JRootPane) {
if (p.getParent() instanceof JInternalFrame) {
continue;
}
parent = ((JRootPane)p).getLayeredPane();
// Continue, so that if there is a higher JRootPane, we'll
// pick it up.
} else if(p instanceof Window) {
if (parent == null) {
parent = p;
}
break;
} else if (p instanceof JApplet) {
// Painting code stops at Applets, we don't want
// to add to a Component above an Applet otherwise
// you'll never see it painted.
break;
}
}
Point p = SwingUtilities.convertScreenLocationToParent(parent, x,
y);
Component component = getComponent();
component.setLocation(p.x, p.y);
if (parent instanceof JLayeredPane) {
parent.add(component, JLayeredPane.POPUP_LAYER, 0);
} else {
parent.add(component);
}
}
Component createComponent(Component owner) {
JComponent component = new JPanel(new BorderLayout(), true);
component.setOpaque(true);
return component;
}
//
// Local methods
//
/**
* Resets the <code>Popup</code> to an initial state.
*/
void reset(Component owner, Component contents, int ownerX,
int ownerY) {
super.reset(owner, contents, ownerX, ownerY);
JComponent component = (JComponent)getComponent();
component.setOpaque(contents.isOpaque());
component.setLocation(ownerX, ownerY);
component.add(contents, BorderLayout.CENTER);
contents.invalidate();
pack();
}
}
/**
* Popup implementation that uses a Panel as the popup.
*/
private static class MediumWeightPopup extends ContainerPopup {
private static final Object mediumWeightPopupCacheKey =
new StringBuffer("PopupFactory.mediumPopupCache");
/** Child of the panel. The contents are added to this. */
private JRootPane rootPane;
/**
* Returns a medium weight <code>Popup</code> implementation. If
* the <code>Popup</code> needs more space that in available in
* <code>owner</code>, this will return null.
*/
static Popup getMediumWeightPopup(Component owner, Component contents,
int ownerX, int ownerY) {
MediumWeightPopup popup = getRecycledMediumWeightPopup();
if (popup == null) {
popup = new MediumWeightPopup();
}
popup.reset(owner, contents, ownerX, ownerY);
if (!popup.fitsOnScreen() ||
popup.overlappedByOwnedWindow()) {
popup.hide();
return null;
}
return popup;
}
/**
* Returns the cache to use for medium weight popups.
*/
@SuppressWarnings("unchecked")
private static List<MediumWeightPopup> getMediumWeightPopupCache() {
List<MediumWeightPopup> cache = (List<MediumWeightPopup>)SwingUtilities.appContextGet(
mediumWeightPopupCacheKey);
if (cache == null) {
cache = new ArrayList<>();
SwingUtilities.appContextPut(mediumWeightPopupCacheKey, cache);
}
return cache;
}
/**
* Recycles the MediumWeightPopup <code>popup</code>.
*/
private static void recycleMediumWeightPopup(MediumWeightPopup popup) {
synchronized (MediumWeightPopup.class) {
List<MediumWeightPopup> mediumPopupCache = getMediumWeightPopupCache();
if (mediumPopupCache.size() < MAX_CACHE_SIZE) {
mediumPopupCache.add(popup);
}
}
}
/**
* Returns a previously used <code>MediumWeightPopup</code>, or null
* if none of the popups have been recycled.
*/
private static MediumWeightPopup getRecycledMediumWeightPopup() {
synchronized (MediumWeightPopup.class) {
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