/*
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* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
*
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* 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 javax.swing;
import java.awt.FocusTraversalPolicy;
import java.awt.Component;
import java.awt.Container;
import java.awt.Window;
import java.util.HashMap;
import java.util.HashSet;
import java.io.*;
/**
* A FocusTraversalPolicy which provides support for legacy applications which
* handle focus traversal via JComponent.setNextFocusableComponent or by
* installing a custom DefaultFocusManager. If a specific traversal has not
* been hard coded, then that traversal is provided either by the custom
* DefaultFocusManager, or by a wrapped FocusTraversalPolicy instance.
*
* @author David Mendenhall
*/
@SuppressWarnings("serial") // JDK-implementation class
final class LegacyGlueFocusTraversalPolicy extends FocusTraversalPolicy
implements Serializable
{
private transient FocusTraversalPolicy delegatePolicy;
private transient DefaultFocusManager delegateManager;
private HashMap<Component, Component> forwardMap = new HashMap<Component, Component>(),
backwardMap = new HashMap<Component, Component>();
LegacyGlueFocusTraversalPolicy(FocusTraversalPolicy delegatePolicy) {
this.delegatePolicy = delegatePolicy;
}
LegacyGlueFocusTraversalPolicy(DefaultFocusManager delegateManager) {
this.delegateManager = delegateManager;
}
void setNextFocusableComponent(Component left, Component right) {
forwardMap.put(left, right);
backwardMap.put(right, left);
}
void unsetNextFocusableComponent(Component left, Component right) {
forwardMap.remove(left);
backwardMap.remove(right);
}
public Component getComponentAfter(Container focusCycleRoot,
Component aComponent) {
Component hardCoded = aComponent, prevHardCoded;
HashSet<Component> sanity = new HashSet<Component>();
do {
prevHardCoded = hardCoded;
hardCoded = forwardMap.get(hardCoded);
if (hardCoded == null) {
if (delegatePolicy != null &&
prevHardCoded.isFocusCycleRoot(focusCycleRoot)) {
return delegatePolicy.getComponentAfter(focusCycleRoot,
prevHardCoded);
} else if (delegateManager != null) {
return delegateManager.
getComponentAfter(focusCycleRoot, aComponent);
} else {
return null;
}
}
if (sanity.contains(hardCoded)) {
// cycle detected; bail
return null;
}
sanity.add(hardCoded);
} while (!accept(hardCoded));
return hardCoded;
}
public Component getComponentBefore(Container focusCycleRoot,
Component aComponent) {
Component hardCoded = aComponent, prevHardCoded;
HashSet<Component> sanity = new HashSet<Component>();
do {
prevHardCoded = hardCoded;
hardCoded = backwardMap.get(hardCoded);
if (hardCoded == null) {
if (delegatePolicy != null &&
prevHardCoded.isFocusCycleRoot(focusCycleRoot)) {
return delegatePolicy.getComponentBefore(focusCycleRoot,
prevHardCoded);
} else if (delegateManager != null) {
return delegateManager.
getComponentBefore(focusCycleRoot, aComponent);
} else {
return null;
}
}
if (sanity.contains(hardCoded)) {
// cycle detected; bail
return null;
}
sanity.add(hardCoded);
} while (!accept(hardCoded));
return hardCoded;
}
public Component getFirstComponent(Container focusCycleRoot) {
if (delegatePolicy != null) {
return delegatePolicy.getFirstComponent(focusCycleRoot);
} else if (delegateManager != null) {
return delegateManager.getFirstComponent(focusCycleRoot);
} else {
return null;
}
}
public Component getLastComponent(Container focusCycleRoot) {
if (delegatePolicy != null) {
return delegatePolicy.getLastComponent(focusCycleRoot);
} else if (delegateManager != null) {
return delegateManager.getLastComponent(focusCycleRoot);
} else {
return null;
}
}
public Component getDefaultComponent(Container focusCycleRoot) {
if (delegatePolicy != null) {
return delegatePolicy.getDefaultComponent(focusCycleRoot);
} else {
return getFirstComponent(focusCycleRoot);
}
}
private boolean accept(Component aComponent) {
if (!(aComponent.isVisible() && aComponent.isDisplayable() &&
aComponent.isFocusable() && aComponent.isEnabled())) {
return false;
}
// Verify that the Component is recursively enabled. Disabling a
// heavyweight Container disables its children, whereas disabling
// a lightweight Container does not.
if (!(aComponent instanceof Window)) {
for (Container enableTest = aComponent.getParent();
enableTest != null;
enableTest = enableTest.getParent())
{
if (!(enableTest.isEnabled() || enableTest.isLightweight())) {
return false;
}
if (enableTest instanceof Window) {
break;
}
}
}
return true;
}
private void writeObject(ObjectOutputStream out) throws IOException {
out.defaultWriteObject();
if (delegatePolicy instanceof Serializable) {
out.writeObject(delegatePolicy);
} else {
out.writeObject(null);
}
if (delegateManager instanceof Serializable) {
out.writeObject(delegateManager);
} else {
out.writeObject(null);
}
}
private void readObject(ObjectInputStream in)
throws IOException, ClassNotFoundException
{
ObjectInputStream.GetField f = in.readFields();
@SuppressWarnings("unchecked")
HashMap<Component, Component> newForwardMap =
(HashMap<Component, Component> ) f.get("forwardMap", null);
if (newForwardMap == null) {
throw new InvalidObjectException("Null forwardMap");
}
forwardMap = newForwardMap;
@SuppressWarnings("unchecked")
HashMap<Component, Component> newBackwardMap =
(HashMap<Component, Component>) f.get("backwardMap", null);
if (newBackwardMap == null) {
throw new InvalidObjectException("Null backwardMap");
}
backwardMap = newBackwardMap;
delegatePolicy = (FocusTraversalPolicy)in.readObject();
delegateManager = (DefaultFocusManager)in.readObject();
}
}