META-INF.modules.java.desktop.classes.javax.swing.LayoutFocusTraversalPolicy Maven / Gradle / Ivy
/*
* Copyright (c) 2000, 2016, 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.Component;
import java.awt.Container;
import java.util.Comparator;
import java.io.*;
import java.util.Enumeration;
import sun.awt.SunToolkit;
/**
* A SortingFocusTraversalPolicy which sorts Components based on their size,
* position, and orientation. Based on their size and position, Components are
* roughly categorized into rows and columns. For a Container with horizontal
* orientation, columns run left-to-right or right-to-left, and rows run top-
* to-bottom. For a Container with vertical orientation, columns run top-to-
* bottom and rows run left-to-right or right-to-left. See
* ComponentOrientation for more information. All columns in a
* row are fully traversed before proceeding to the next row.
*
* @author David Mendenhall
*
* @see java.awt.ComponentOrientation
* @since 1.4
*/
@SuppressWarnings("serial") // Parts of superclass are not serializable across versions
public class LayoutFocusTraversalPolicy extends SortingFocusTraversalPolicy
implements Serializable
{
// Delegate most of our fitness test to Default so that we only have to
// code the algorithm once.
private static final SwingDefaultFocusTraversalPolicy fitnessTestPolicy =
new SwingDefaultFocusTraversalPolicy();
/**
* Constructs a LayoutFocusTraversalPolicy.
*/
public LayoutFocusTraversalPolicy() {
super(new LayoutComparator());
}
/**
* Constructs a LayoutFocusTraversalPolicy with the passed in
* Comparator.
*/
LayoutFocusTraversalPolicy(Comparator c) {
super(c);
}
/**
* Returns the Component that should receive the focus after aComponent.
* aContainer must be a focus cycle root of aComponent.
*
* By default, LayoutFocusTraversalPolicy implicitly transfers focus down-
* cycle. That is, during normal focus traversal, the Component
* traversed after a focus cycle root will be the focus-cycle-root's
* default Component to focus. This behavior can be disabled using the
* setImplicitDownCycleTraversal method.
*
* If aContainer is focus
* traversal policy provider, the focus is always transferred down-cycle.
*
* @param aContainer a focus cycle root of aComponent or a focus traversal policy provider
* @param aComponent a (possibly indirect) child of aContainer, or
* aContainer itself
* @return the Component that should receive the focus after aComponent, or
* null if no suitable Component can be found
* @throws IllegalArgumentException if aContainer is not a focus cycle
* root of aComponent or a focus traversal policy provider, or if either aContainer or
* aComponent is null
*/
public Component getComponentAfter(Container aContainer,
Component aComponent) {
if (aContainer == null || aComponent == null) {
throw new IllegalArgumentException("aContainer and aComponent cannot be null");
}
Comparator comparator = getComparator();
if (comparator instanceof LayoutComparator) {
((LayoutComparator)comparator).
setComponentOrientation(aContainer.
getComponentOrientation());
}
return super.getComponentAfter(aContainer, aComponent);
}
/**
* Returns the Component that should receive the focus before aComponent.
* aContainer must be a focus cycle root of aComponent.
*
* By default, LayoutFocusTraversalPolicy implicitly transfers focus down-
* cycle. That is, during normal focus traversal, the Component
* traversed after a focus cycle root will be the focus-cycle-root's
* default Component to focus. This behavior can be disabled using the
* setImplicitDownCycleTraversal method.
*
* If aContainer is focus
* traversal policy provider, the focus is always transferred down-cycle.
*
* @param aContainer a focus cycle root of aComponent or a focus traversal policy provider
* @param aComponent a (possibly indirect) child of aContainer, or
* aContainer itself
* @return the Component that should receive the focus before aComponent,
* or null if no suitable Component can be found
* @throws IllegalArgumentException if aContainer is not a focus cycle
* root of aComponent or a focus traversal policy provider, or if either aContainer or
* aComponent is null
*/
public Component getComponentBefore(Container aContainer,
Component aComponent) {
if (aContainer == null || aComponent == null) {
throw new IllegalArgumentException("aContainer and aComponent cannot be null");
}
Comparator comparator = getComparator();
if (comparator instanceof LayoutComparator) {
((LayoutComparator)comparator).
setComponentOrientation(aContainer.
getComponentOrientation());
}
return super.getComponentBefore(aContainer, aComponent);
}
/**
* Returns the first Component in the traversal cycle. This method is used
* to determine the next Component to focus when traversal wraps in the
* forward direction.
*
* @param aContainer a focus cycle root of aComponent or a focus traversal policy provider whose
* first Component is to be returned
* @return the first Component in the traversal cycle of aContainer,
* or null if no suitable Component can be found
* @throws IllegalArgumentException if aContainer is null
*/
public Component getFirstComponent(Container aContainer) {
if (aContainer == null) {
throw new IllegalArgumentException("aContainer cannot be null");
}
Comparator comparator = getComparator();
if (comparator instanceof LayoutComparator) {
((LayoutComparator)comparator).
setComponentOrientation(aContainer.
getComponentOrientation());
}
return super.getFirstComponent(aContainer);
}
/**
* Returns the last Component in the traversal cycle. This method is used
* to determine the next Component to focus when traversal wraps in the
* reverse direction.
*
* @param aContainer a focus cycle root of aComponent or a focus traversal policy provider whose
* last Component is to be returned
* @return the last Component in the traversal cycle of aContainer,
* or null if no suitable Component can be found
* @throws IllegalArgumentException if aContainer is null
*/
public Component getLastComponent(Container aContainer) {
if (aContainer == null) {
throw new IllegalArgumentException("aContainer cannot be null");
}
Comparator comparator = getComparator();
if (comparator instanceof LayoutComparator) {
((LayoutComparator)comparator).
setComponentOrientation(aContainer.
getComponentOrientation());
}
return super.getLastComponent(aContainer);
}
/**
* Determines whether the specified Component
* is an acceptable choice as the new focus owner.
* This method performs the following sequence of operations:
*
* - Checks whether
aComponent is visible, displayable,
* enabled, and focusable. If any of these properties is
* false, this method returns false.
* - If
aComponent is an instance of JTable,
* returns true.
* - If
aComponent is an instance of JComboBox,
* then returns the value of
* aComponent.getUI().isFocusTraversable(aComponent).
* - If
aComponent is a JComponent
* with a JComponent.WHEN_FOCUSED
* InputMap that is neither null
* nor empty, returns true.
* - Returns the value of
*
DefaultFocusTraversalPolicy.accept(aComponent).
*
*
* @param aComponent the Component whose fitness
* as a focus owner is to be tested
* @see java.awt.Component#isVisible
* @see java.awt.Component#isDisplayable
* @see java.awt.Component#isEnabled
* @see java.awt.Component#isFocusable
* @see javax.swing.plaf.ComboBoxUI#isFocusTraversable
* @see javax.swing.JComponent#getInputMap
* @see java.awt.DefaultFocusTraversalPolicy#accept
* @return true if aComponent is a valid choice
* for a focus owner;
* otherwise false
*/
protected boolean accept(Component aComponent) {
if (!super.accept(aComponent)) {
return false;
} else if (SunToolkit.isInstanceOf(aComponent, "javax.swing.JTable")) {
// JTable only has ancestor focus bindings, we thus force it
// to be focusable by returning true here.
return true;
} else if (SunToolkit.isInstanceOf(aComponent, "javax.swing.JComboBox")) {
JComboBox box = (JComboBox)aComponent;
return box.getUI().isFocusTraversable(box);
} else if (aComponent instanceof JComponent) {
if (SunToolkit.isInstanceOf(aComponent,
"javax.swing.JToggleButton")) {
ButtonModel model = ((JToggleButton)aComponent).getModel();
if (model != null) {
ButtonGroup group = model.getGroup();
if (group != null) {
Enumeration elements =
group.getElements();
int idx = 0;
while (elements.hasMoreElements()) {
AbstractButton member = elements.nextElement();
if (member instanceof JToggleButton &&
member.isVisible() && member.isDisplayable() &&
member.isEnabled() && member.isFocusable()) {
if (member == aComponent) {
return idx == 0;
}
idx++;
}
}
}
}
}
JComponent jComponent = (JComponent)aComponent;
InputMap inputMap = jComponent.getInputMap(JComponent.WHEN_FOCUSED,
false);
while (inputMap != null && inputMap.size() == 0) {
inputMap = inputMap.getParent();
}
if (inputMap != null) {
return true;
}
// Delegate to the fitnessTestPolicy, this will test for the
// case where the developer has overriden isFocusTraversable to
// return true.
}
return fitnessTestPolicy.accept(aComponent);
}
private void writeObject(ObjectOutputStream out) throws IOException {
out.writeObject(getComparator());
out.writeBoolean(getImplicitDownCycleTraversal());
}
@SuppressWarnings("unchecked") // Cast to (Comparator)
private void readObject(ObjectInputStream in)
throws IOException, ClassNotFoundException
{
setComparator((Comparator)in.readObject());
setImplicitDownCycleTraversal(in.readBoolean());
}
}
// Create our own subclass and change accept to public so that we can call
// accept.
@SuppressWarnings("serial") // JDK-implementation class
class SwingDefaultFocusTraversalPolicy
extends java.awt.DefaultFocusTraversalPolicy
{
public boolean accept(Component aComponent) {
return super.accept(aComponent);
}
}