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 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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 * published by the Free Software Foundation.  Oracle designates this
 * particular file as subject to the "Classpath" exception as provided
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 * 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).
 *
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 * 2 along with this work; if not, write to the Free Software Foundation,
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 *
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package javax.swing;

import java.awt.Component;
import java.awt.Container;
import java.awt.FocusTraversalPolicy;
import java.util.Comparator;


This class has been obsoleted by the 1.4 focus APIs. While client code may
still use this class, developers are strongly encouraged to use
java.awt.KeyboardFocusManager and
java.awt.DefaultKeyboardFocusManager instead.

Please see

How to Use the Focus Subsystem,
a section in The Java Tutorial, and the
Focus Specification
for more information.
Author:
Arnaud Weber, David Mendenhall
Since:
1.2/**
 * This class has been obsoleted by the 1.4 focus APIs. While client code may
 * still use this class, developers are strongly encouraged to use
 * <code>java.awt.KeyboardFocusManager</code> and
 * <code>java.awt.DefaultKeyboardFocusManager</code> instead.
 * <p>
 * Please see
 * <a href="https://docs.oracle.com/javase/tutorial/uiswing/misc/focus.html">
 * How to Use the Focus Subsystem</a>,
 * a section in <em>The Java Tutorial</em>, and the
 * <a href="../../java/awt/doc-files/FocusSpec.html">Focus Specification</a>
 * for more information.
 *
 * @author Arnaud Weber
 * @author David Mendenhall
 * @since 1.2
 */
@SuppressWarnings("serial") // Obsolete class
public class DefaultFocusManager extends FocusManager {

    final FocusTraversalPolicy gluePolicy =
        new LegacyGlueFocusTraversalPolicy(this);
    private final FocusTraversalPolicy layoutPolicy =
        new LegacyLayoutFocusTraversalPolicy(this);
    private final LayoutComparator comparator =
        new LayoutComparator();

    
Constructs a DefaultFocusManager. /**
     * Constructs a {@code DefaultFocusManager}.
     */
    public DefaultFocusManager() {
        setDefaultFocusTraversalPolicy(gluePolicy);
    }

    
Returns the component after.
Params:
aContainer – a container
aComponent – a component
Returns:
the component after/**
     * Returns the component after.
     * @return the component after
     * @param aContainer a container
     * @param aComponent a component
     */
    public Component getComponentAfter(Container aContainer,
                                       Component aComponent)
    {
        Container root = (aContainer.isFocusCycleRoot())
            ? aContainer
            : aContainer.getFocusCycleRootAncestor();

        // Support for mixed 1.4/pre-1.4 focus APIs. If a particular root's
        // traversal policy is non-legacy, then honor it.
        if (root != null) {
            FocusTraversalPolicy policy = root.getFocusTraversalPolicy();
            if (policy != gluePolicy) {
                return policy.getComponentAfter(root, aComponent);
            }

            comparator.setComponentOrientation(root.getComponentOrientation());
            return layoutPolicy.getComponentAfter(root, aComponent);
        }

        return null;
    }

    
Returns the component before.
Params:
aContainer – a container
aComponent – a component
Returns:
the component before/**
     * Returns the component before.
     * @return the component before
     * @param aContainer a container
     * @param aComponent a component
     */
    public Component getComponentBefore(Container aContainer,
                                        Component aComponent)
    {
        Container root = (aContainer.isFocusCycleRoot())
            ? aContainer
            : aContainer.getFocusCycleRootAncestor();

        // Support for mixed 1.4/pre-1.4 focus APIs. If a particular root's
        // traversal policy is non-legacy, then honor it.
        if (root != null) {
            FocusTraversalPolicy policy = root.getFocusTraversalPolicy();
            if (policy != gluePolicy) {
                return policy.getComponentBefore(root, aComponent);
            }

            comparator.setComponentOrientation(root.getComponentOrientation());
            return layoutPolicy.getComponentBefore(root, aComponent);
        }

        return null;
    }

    
Returns the first component.
Params:
aContainer – a container
Returns:
the first component/**
     * Returns the first component.
     * @return the first component
     * @param aContainer a container
     */
    public Component getFirstComponent(Container aContainer) {
        Container root = (aContainer.isFocusCycleRoot())
            ? aContainer
            : aContainer.getFocusCycleRootAncestor();

        // Support for mixed 1.4/pre-1.4 focus APIs. If a particular root's
        // traversal policy is non-legacy, then honor it.
        if (root != null) {
            FocusTraversalPolicy policy = root.getFocusTraversalPolicy();
            if (policy != gluePolicy) {
                return policy.getFirstComponent(root);
            }

            comparator.setComponentOrientation(root.getComponentOrientation());
            return layoutPolicy.getFirstComponent(root);
        }

        return null;
    }

    
Returns the last component.
Params:
aContainer – a container
Returns:
the last component/**
     * Returns the last component.
     * @return the last component
     * @param aContainer a container
     */
    public Component getLastComponent(Container aContainer) {
        Container root = (aContainer.isFocusCycleRoot())
            ? aContainer
            : aContainer.getFocusCycleRootAncestor();

        // Support for mixed 1.4/pre-1.4 focus APIs. If a particular root's
        // traversal policy is non-legacy, then honor it.
        if (root != null) {
            FocusTraversalPolicy policy = root.getFocusTraversalPolicy();
            if (policy != gluePolicy) {
                return policy.getLastComponent(root);
            }

            comparator.setComponentOrientation(root.getComponentOrientation());
            return layoutPolicy.getLastComponent(root);
        }

        return null;
    }

    
Compares the components by their focus traversal cycle order.
Params:
a – the first component
b – the second component
Returns:
a comparison of the components by their focus traversal cycle order/**
     * Compares the components by their focus traversal cycle order.
     * @param a the first component
     * @param b the second component
     * @return a comparison of the components by their focus traversal cycle order
     */
    public boolean compareTabOrder(Component a, Component b) {
        return (comparator.compare(a, b) < 0);
    }
}

@SuppressWarnings("serial") // JDK-implementation class
final class LegacyLayoutFocusTraversalPolicy
    extends LayoutFocusTraversalPolicy
{
    LegacyLayoutFocusTraversalPolicy(DefaultFocusManager defaultFocusManager) {
        super(new CompareTabOrderComparator(defaultFocusManager));
    }
}

final class CompareTabOrderComparator implements Comparator<Component> {
    private final DefaultFocusManager defaultFocusManager;

    CompareTabOrderComparator(DefaultFocusManager defaultFocusManager) {
        this.defaultFocusManager = defaultFocusManager;
    }

    public int compare(Component o1, Component o2) {
        if (o1 == o2) {
            return 0;
        }
        return (defaultFocusManager.compareTabOrder(o1, o2)) ? -1 : 1;
    }
}