Java example source code file (EmbeddedFrame.java)
The EmbeddedFrame.java Java example source code
/*
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* 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.
*
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package sun.awt;
import java.awt.*;
import java.awt.event.*;
import java.awt.image.*;
import java.awt.peer.*;
import java.beans.PropertyChangeListener;
import java.beans.PropertyChangeEvent;
import java.util.Set;
import java.awt.AWTKeyStroke;
import java.applet.Applet;
import sun.applet.AppletPanel;
/**
* A generic container used for embedding Java components, usually applets.
* An EmbeddedFrame has two related uses:
*
* . Within a Java-based application, an EmbeddedFrame serves as a sort of
* firewall, preventing the contained components or applets from using
* getParent() to find parent components, such as menubars.
*
* . Within a C-based application, an EmbeddedFrame contains a window handle
* which was created by the application, which serves as the top-level
* Java window. EmbeddedFrames created for this purpose are passed-in a
* handle of an existing window created by the application. The window
* handle should be of the appropriate native type for a specific
* platform, as stored in the pData field of the ComponentPeer.
*
* @author Thomas Ball
*/
public abstract class EmbeddedFrame extends Frame
implements KeyEventDispatcher, PropertyChangeListener {
private boolean isCursorAllowed = true;
private boolean supportsXEmbed = false;
private KeyboardFocusManager appletKFM;
// JDK 1.1 compatibility
private static final long serialVersionUID = 2967042741780317130L;
/*
* The constants define focus traversal directions.
* Use them in {@code traverseIn}, {@code traverseOut} methods.
*/
protected static final boolean FORWARD = true;
protected static final boolean BACKWARD = false;
public boolean supportsXEmbed() {
return supportsXEmbed && SunToolkit.needsXEmbed();
}
protected EmbeddedFrame(boolean supportsXEmbed) {
this((long)0, supportsXEmbed);
}
protected EmbeddedFrame() {
this((long)0);
}
/**
* @deprecated This constructor will be removed in 1.5
*/
@Deprecated
protected EmbeddedFrame(int handle) {
this((long)handle);
}
protected EmbeddedFrame(long handle) {
this(handle, false);
}
protected EmbeddedFrame(long handle, boolean supportsXEmbed) {
this.supportsXEmbed = supportsXEmbed;
registerListeners();
}
/**
* Block introspection of a parent window by this child.
*/
public Container getParent() {
return null;
}
/**
* Needed to track which KeyboardFocusManager is current. We want to avoid memory
* leaks, so when KFM stops being current, we remove ourselves as listeners.
*/
public void propertyChange(PropertyChangeEvent evt) {
// We don't handle any other properties. Skip it.
if (!evt.getPropertyName().equals("managingFocus")) {
return;
}
// We only do it if it stops being current. Technically, we should
// never get an event about KFM starting being current.
if (evt.getNewValue() == Boolean.TRUE) {
return;
}
// should be the same as appletKFM
removeTraversingOutListeners((KeyboardFocusManager)evt.getSource());
appletKFM = KeyboardFocusManager.getCurrentKeyboardFocusManager();
if (isVisible()) {
addTraversingOutListeners(appletKFM);
}
}
/**
* Register us as KeyEventDispatcher and property "managingFocus" listeners.
*/
private void addTraversingOutListeners(KeyboardFocusManager kfm) {
kfm.addKeyEventDispatcher(this);
kfm.addPropertyChangeListener("managingFocus", this);
}
/**
* Deregister us as KeyEventDispatcher and property "managingFocus" listeners.
*/
private void removeTraversingOutListeners(KeyboardFocusManager kfm) {
kfm.removeKeyEventDispatcher(this);
kfm.removePropertyChangeListener("managingFocus", this);
}
/**
* Because there may be many AppContexts, and we can't be sure where this
* EmbeddedFrame is first created or shown, we can't automatically determine
* the correct KeyboardFocusManager to attach to as KeyEventDispatcher.
* Those who want to use the functionality of traversing out of the EmbeddedFrame
* must call this method on the Applet's AppContext. After that, all the changes
* can be handled automatically, including possible replacement of
* KeyboardFocusManager.
*/
public void registerListeners() {
if (appletKFM != null) {
removeTraversingOutListeners(appletKFM);
}
appletKFM = KeyboardFocusManager.getCurrentKeyboardFocusManager();
if (isVisible()) {
addTraversingOutListeners(appletKFM);
}
}
/**
* Needed to avoid memory leak: we register this EmbeddedFrame as a listener with
* KeyboardFocusManager of applet's AppContext. We don't want the KFM to keep
* reference to our EmbeddedFrame forever if the Frame is no longer in use, so we
* add listeners in show() and remove them in hide().
*/
@SuppressWarnings("deprecation")
public void show() {
if (appletKFM != null) {
addTraversingOutListeners(appletKFM);
}
super.show();
}
/**
* Needed to avoid memory leak: we register this EmbeddedFrame as a listener with
* KeyboardFocusManager of applet's AppContext. We don't want the KFM to keep
* reference to our EmbeddedFrame forever if the Frame is no longer in use, so we
* add listeners in show() and remove them in hide().
*/
@SuppressWarnings("deprecation")
public void hide() {
if (appletKFM != null) {
removeTraversingOutListeners(appletKFM);
}
super.hide();
}
/**
* Need this method to detect when the focus may have chance to leave the
* focus cycle root which is EmbeddedFrame. Mostly, the code here is copied
* from DefaultKeyboardFocusManager.processKeyEvent with some minor
* modifications.
*/
public boolean dispatchKeyEvent(KeyEvent e) {
Container currentRoot = AWTAccessor.getKeyboardFocusManagerAccessor()
.getCurrentFocusCycleRoot();
// if we are not in EmbeddedFrame's cycle, we should not try to leave.
if (this != currentRoot) {
return false;
}
// KEY_TYPED events cannot be focus traversal keys
if (e.getID() == KeyEvent.KEY_TYPED) {
return false;
}
if (!getFocusTraversalKeysEnabled() || e.isConsumed()) {
return false;
}
AWTKeyStroke stroke = AWTKeyStroke.getAWTKeyStrokeForEvent(e);
Set<AWTKeyStroke> toTest;
Component currentFocused = e.getComponent();
toTest = getFocusTraversalKeys(KeyboardFocusManager.FORWARD_TRAVERSAL_KEYS);
if (toTest.contains(stroke)) {
// 6581899: performance improvement for SortingFocusTraversalPolicy
Component last = getFocusTraversalPolicy().getLastComponent(this);
if (currentFocused == last || last == null) {
if (traverseOut(FORWARD)) {
e.consume();
return true;
}
}
}
toTest = getFocusTraversalKeys(KeyboardFocusManager.BACKWARD_TRAVERSAL_KEYS);
if (toTest.contains(stroke)) {
// 6581899: performance improvement for SortingFocusTraversalPolicy
Component first = getFocusTraversalPolicy().getFirstComponent(this);
if (currentFocused == first || first == null) {
if (traverseOut(BACKWARD)) {
e.consume();
return true;
}
}
}
return false;
}
/**
* This method is called by the embedder when we should receive focus as element
* of the traversal chain. The method requests focus on:
* 1. the first Component of this EmbeddedFrame if user moves focus forward
* in the focus traversal cycle.
* 2. the last Component of this EmbeddedFrame if user moves focus backward
* in the focus traversal cycle.
*
* The direction parameter specifies which of the two mentioned cases is
* happening. Use FORWARD and BACKWARD constants defined in the EmbeddedFrame class
* to avoid confusing boolean values.
*
* A concrete implementation of this method is defined in the platform-dependent
* subclasses.
*
* @param direction FORWARD or BACKWARD
* @return true, if the EmbeddedFrame wants to get focus, false otherwise.
*/
public boolean traverseIn(boolean direction) {
Component comp = null;
if (direction == FORWARD) {
comp = getFocusTraversalPolicy().getFirstComponent(this);
} else {
comp = getFocusTraversalPolicy().getLastComponent(this);
}
if (comp != null) {
// comp.requestFocus(); - Leads to a hung.
AWTAccessor.getKeyboardFocusManagerAccessor().setMostRecentFocusOwner(this, comp);
synthesizeWindowActivation(true);
}
return (null != comp);
}
/**
* This method is called from dispatchKeyEvent in the following two cases:
* 1. The focus is on the first Component of this EmbeddedFrame and we are
* about to transfer the focus backward.
* 2. The focus in on the last Component of this EmbeddedFrame and we are
* about to transfer the focus forward.
* This is needed to give the opportuity for keyboard focus to leave the
* EmbeddedFrame. Override this method, initiate focus transfer in it and
* return true if you want the focus to leave EmbeddedFrame's cycle.
* The direction parameter specifies which of the two mentioned cases is
* happening. Use FORWARD and BACKWARD constants defined in EmbeddedFrame
* to avoid confusing boolean values.
*
* @param direction FORWARD or BACKWARD
* @return true, if EmbeddedFrame wants the focus to leave it,
* false otherwise.
*/
protected boolean traverseOut(boolean direction) {
return false;
}
/**
* Block modifying any frame attributes, since they aren't applicable
* for EmbeddedFrames.
*/
public void setTitle(String title) {}
public void setIconImage(Image image) {}
public void setIconImages(java.util.List<? extends Image> icons) {}
public void setMenuBar(MenuBar mb) {}
public void setResizable(boolean resizable) {}
public void remove(MenuComponent m) {}
public boolean isResizable() {
return true;
}
@SuppressWarnings("deprecation")
public void addNotify() {
synchronized (getTreeLock()) {
if (getPeer() == null) {
setPeer(new NullEmbeddedFramePeer());
}
super.addNotify();
}
}
// These three functions consitute RFE 4100710. Do not remove.
@SuppressWarnings("deprecation")
public void setCursorAllowed(boolean isCursorAllowed) {
this.isCursorAllowed = isCursorAllowed;
getPeer().updateCursorImmediately();
}
public boolean isCursorAllowed() {
return isCursorAllowed;
}
public Cursor getCursor() {
return (isCursorAllowed)
? super.getCursor()
: Cursor.getPredefinedCursor(Cursor.DEFAULT_CURSOR);
}
@SuppressWarnings("deprecation")
protected void setPeer(final ComponentPeer p){
AWTAccessor.getComponentAccessor().setPeer(EmbeddedFrame.this, p);
};
/**
* Synthesize native message to activate or deactivate EmbeddedFrame window
* depending on the value of parameter <code>b.
* Peers should override this method if they are to implement
* this functionality.
* @param doActivate if <code>true, activates the window;
* otherwise, deactivates the window
*/
public void synthesizeWindowActivation(boolean doActivate) {}
/**
* Moves this embedded frame to a new location. The top-left corner of
* the new location is specified by the <code>x and
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