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	/*
	* Copyright (c) 2000, 2008, 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
	* or visit www.oracle.com if you need additional information or have any
	* questions.
	*/
	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
	*/
	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
	{
	in.defaultReadObject();
	delegatePolicy = (FocusTraversalPolicy)in.readObject();
	delegateManager = (DefaultFocusManager)in.readObject();
	}
	}

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