/*
* @(#)ContainerOrderFocusTraversalPolicy.java 1.8 03/12/19
*
* Copyright 2004 Sun Microsystems, Inc. All rights reserved.
* SUN PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
*/
package java.awt;
import java.util.logging.*;
/**
* A FocusTraversalPolicy that determines traversal order based on the order
* of child Components in a Container. From a particular focus cycle root, the
* policy makes a pre-order traversal of the Component hierarchy, and traverses
* a Container's children according to the ordering of the array returned by
* <code>Container.getComponents()</code>. Portions of the hierarchy that are
* not visible and displayable will not be searched.
* <p>
* By default, ContainerOrderFocusTraversalPolicy implicitly transfers focus
* down-cycle. That is, during normal forward 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
* <code>setImplicitDownCycleTraversal</code> method.
* <p>
* By default, methods of this class with return a Component only if it is
* visible, displayable, enabled, and focusable. Subclasses can modify this
* behavior by overriding the <code>accept</code> method.
* <p>
* This policy takes into account <a
* href="doc-files/FocusSpec.html#FocusTraversalPolicyProviders">focus traversal
* policy providers</a>. When searching for first/last/next/previous Component,
* if a focus traversal policy provider is encountered, its focus traversal
* policy is used to perform the search operation.
*
* @author David Mendenhall
* @version 1.8, 12/19/03
*
* @see Container#getComponents
* @since 1.4
*/
public class ContainerOrderFocusTraversalPolicy extends FocusTraversalPolicy
implements java.io.Serializable
{
private static final MutableBoolean found = new MutableBoolean();
private static final Logger log = Logger.getLogger("java.awt.ContainerOrderFocusTraversalPolicy");
/*
* JDK 1.4 serialVersionUID
*/
private static final long serialVersionUID = 486933713763926351L;
private boolean implicitDownCycleTraversal = true;
/**
* Returns the Component that should receive the focus after aComponent.
* aContainer must be a focus cycle root of aComponent or a focus traversal policy provider.
* <p>
* By default, ContainerOrderFocusTraversalPolicy implicitly transfers
* focus down-cycle. That is, during normal forward 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 <code>setImplicitDownCycleTraversal</code> method.
* <p>
* If aContainer is <a href="doc-files/FocusSpec.html#FocusTraversalPolicyProviders">focus
* traversal policy provider</a>, 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 focus traversal policy provider, or if either aContainer or
* aComponent is null
*/
public Component getComponentAfter(Container aContainer,
Component aComponent) {
if (log.isLoggable(Level.FINE)) log.fine("Looking for next component in " + aContainer + " for " + aComponent);
if (aContainer == null || aComponent == null) {
throw new IllegalArgumentException("aContainer and aComponent cannot be null");
}
if (!aContainer.isFocusTraversalPolicyProvider() && !aContainer.isFocusCycleRoot()) {
throw new IllegalArgumentException("aContainer should be focus cycle root or focus traversal policy provider");
} else if (aContainer.isFocusCycleRoot() && !aComponent.isFocusCycleRoot(aContainer)) {
throw new IllegalArgumentException("aContainer is not a focus cycle root of aComponent");
}
synchronized(aContainer.getTreeLock()) {
found.value = false;
Component retval = getComponentAfter(aContainer, aComponent,
found);
if (retval != null) {
if (log.isLoggable(Level.FINE)) log.fine("After component is " + retval);
return retval;
} else if (found.value) {
if (log.isLoggable(Level.FINE)) log.fine("Didn't find next component in " + aContainer + " - falling back to the first ");
return getFirstComponent(aContainer);
} else {
if (log.isLoggable(Level.FINE)) log.fine("After component is null");
return null;
}
}
}
private Component getComponentAfter(Container aContainer,
Component aComponent,
MutableBoolean found) {
if (!(aContainer.isVisible() && aContainer.isDisplayable())) {
return null;
}
if (found.value) {
if (accept(aContainer)) {
return aContainer;
}
} else if (aContainer == aComponent) {
found.value = true;
}
for (int i = 0; i < aContainer.ncomponents; i++) {
Component comp = aContainer.component[i];
if ((comp instanceof Container) &&
!((Container)comp).isFocusCycleRoot()) {
Component retval = null;
if (((Container)comp).isFocusTraversalPolicyProvider()) {
if (log.isLoggable(Level.FINE)) log.fine("Entering FTP " + comp);
Container cont = (Container) comp;
FocusTraversalPolicy policy = cont.getFocusTraversalPolicy();
if (log.isLoggable(Level.FINE)) log.fine("FTP contains " + aComponent + ": " + cont.isAncestorOf(aComponent));
if (found.value) {
retval = policy.getDefaultComponent(cont);
if (log.isLoggable(Level.FINE)) log.fine("Used FTP for getting default component: " + retval);
} else {
found.value = cont.isAncestorOf(aComponent);
if (found.value) {
if (aComponent == policy.getLastComponent(cont)) {
// Reached last component, going to wrap - should switch to next provider
retval = null;
} else {
retval = policy.getComponentAfter(cont, aComponent);
if (log.isLoggable(Level.FINE)) log.fine("FTP found next for the component : " + retval);
}
}
}
} else {
retval = getComponentAfter((Container)comp,
aComponent,
found);
}
if (retval != null) {
return retval;
}
} else if (found.value) {
if (accept(comp)) {
return comp;
}
} else if (comp == aComponent) {
found.value = true;
}
if (found.value &&
getImplicitDownCycleTraversal() &&
(comp instanceof Container) &&
((Container)comp).isFocusCycleRoot())
{
Container cont = (Container)comp;
Component retval = cont.getFocusTraversalPolicy().
getDefaultComponent(cont);
if (retval != null) {
return retval;
}
}
}
return null;
}
/**
* Returns the Component that should receive the focus before aComponent.
* aContainer must be a focus cycle root of aComponent or a <a
* href="doc-files/FocusSpec.html#FocusTraversalPolicyProviders">focus traversal policy
* provider</a>.
*
* @param aContainer a focus cycle root of aComponent or 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 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");
}
if (!aContainer.isFocusTraversalPolicyProvider() && !aContainer.isFocusCycleRoot()) {
throw new IllegalArgumentException("aContainer should be focus cycle root or focus traversal policy provider");
} else if (aContainer.isFocusCycleRoot() && !aComponent.isFocusCycleRoot(aContainer)) {
throw new IllegalArgumentException("aContainer is not a focus cycle root of aComponent");
}
synchronized(aContainer.getTreeLock()) {
found.value = false;
Component retval = getComponentBefore(aContainer, aComponent,
found);
if (retval != null) {
if (log.isLoggable(Level.FINE)) log.fine("Before component is " + retval);
return retval;
} else if (found.value) {
if (log.isLoggable(Level.FINE)) log.fine("Didn't find before component in " + aContainer + " - falling back to the first ");
return getLastComponent(aContainer);
} else {
if (log.isLoggable(Level.FINE)) log.fine("Before component is null");
return null;
}
}
}
private Component getComponentBefore(Container aContainer,
Component aComponent,
MutableBoolean found) {
if (!(aContainer.isVisible() && aContainer.isDisplayable())) {
return null;
}
for (int i = aContainer.ncomponents - 1; i >= 0; i--) {
Component comp = aContainer.component[i];
if (comp == aComponent) {
found.value = true;
} else if ((comp instanceof Container) &&
!((Container)comp).isFocusCycleRoot()) {
Component retval = null;
if (((Container)comp).isFocusTraversalPolicyProvider()) {
if (log.isLoggable(Level.FINE)) log.fine("Entering FTP " + comp);
Container cont = (Container) comp;
FocusTraversalPolicy policy = cont.getFocusTraversalPolicy();
if (log.isLoggable(Level.FINE)) log.fine("FTP contains " + aComponent + ": " + cont.isAncestorOf(aComponent));
if (found.value) {
retval = policy.getLastComponent(cont);
if (log.isLoggable(Level.FINE)) log.fine("Used FTP for getting last component: " + retval);
} else {
found.value = cont.isAncestorOf(aComponent);
if (found.value) {
if (aComponent == policy.getFirstComponent(cont)) {
retval = null;
} else {
retval = policy.getComponentBefore(cont, aComponent);
if (log.isLoggable(Level.FINE)) log.fine("FTP found previous for the component : " + retval);
}
}
}
} else {
retval = getComponentBefore((Container)comp,
aComponent,
found);
}
if (retval != null) {
return retval;
}
} else if (found.value) {
if (accept(comp)) {
return comp;
}
}
}
if (found.value) {
if (accept(aContainer)) {
return aContainer;
}
} else if (aContainer == aComponent) {
found.value = true;
}
return null;
}
/**
* 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 the focus cycle root or 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");
}
synchronized(aContainer.getTreeLock()) {
if (!(aContainer.isVisible() &&
aContainer.isDisplayable()))
{
return null;
}
if (accept(aContainer)) {
return aContainer;
}
for (int i = 0; i < aContainer.ncomponents; i++) {
Component comp = aContainer.component[i];
if (comp instanceof Container &&
!((Container)comp).isFocusCycleRoot())
{
Component retval = null;
Container cont = (Container)comp;
if (cont.isFocusTraversalPolicyProvider()) {
FocusTraversalPolicy policy = cont.getFocusTraversalPolicy();
retval = policy.getDefaultComponent(cont);
} else {
retval = getFirstComponent((Container)comp);
}
if (retval != null) {
return retval;
}
} else if (accept(comp)) {
return comp;
}
}
}
return null;
}
/**
* 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 the focus cycle root or 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");
}
if (log.isLoggable(Level.FINE)) log.fine("Looking for the last component in " + aContainer);
synchronized(aContainer.getTreeLock()) {
if (!(aContainer.isVisible() &&
aContainer.isDisplayable()))
{
return null;
}
for (int i = aContainer.ncomponents - 1; i >= 0; i--) {
Component comp = aContainer.component[i];
if (comp instanceof Container &&
!((Container)comp).isFocusCycleRoot())
{
Component retval = null;
Container cont = (Container)comp;
if (cont.isFocusTraversalPolicyProvider()) {
if (log.isLoggable(Level.FINE)) log.fine("\tEntering FTP " + cont);
FocusTraversalPolicy policy = cont.getFocusTraversalPolicy();
retval = policy.getLastComponent(cont);
} else {
if (log.isLoggable(Level.FINE)) log.fine("\tEntering sub-container");
retval = getLastComponent((Container)comp);
}
if (retval != null) {
if (log.isLoggable(Level.FINE)) log.fine("\tFound last component : " + retval);
return retval;
}
} else if (accept(comp)) {
return comp;
}
}
if (accept(aContainer)) {
return aContainer;
}
}
return null;
}
/**
* Returns the default Component to focus. This Component will be the first
* to receive focus when traversing down into a new focus traversal cycle
* rooted at aContainer. The default implementation of this method
* returns the same Component as <code>getFirstComponent</code>.
*
* @param aContainer the focus cycle root or focus traversal policy provider whose default
* Component is to be returned
* @return the default Component in the traversal cycle of aContainer,
* or null if no suitable Component can be found
* @see #getFirstComponent
* @throws IllegalArgumentException if aContainer is null
*/
public Component getDefaultComponent(Container aContainer) {
return getFirstComponent(aContainer);
}
/**
* Sets whether this ContainerOrderFocusTraversalPolicy transfers focus
* down-cycle implicitly. If <code>true</code>, during normal forward focus
* traversal, the Component traversed after a focus cycle root will be the
* focus-cycle-root's default Component to focus. If <code>false</code>,
* the next Component in the focus traversal cycle rooted at the specified
* focus cycle root will be traversed instead. The default value for this
* property is <code>true</code>.
*
* @param implicitDownCycleTraversal whether this
* ContainerOrderFocusTraversalPolicy transfers focus down-cycle
* implicitly
* @see #getImplicitDownCycleTraversal
* @see #getFirstComponent
*/
public void setImplicitDownCycleTraversal(boolean
implicitDownCycleTraversal) {
this.implicitDownCycleTraversal = implicitDownCycleTraversal;
}
/**
* Returns whether this ContainerOrderFocusTraversalPolicy transfers focus
* down-cycle implicitly. If <code>true</code>, during normal forward focus
* traversal, the Component traversed after a focus cycle root will be the
* focus-cycle-root's default Component to focus. If <code>false</code>,
* the next Component in the focus traversal cycle rooted at the specified
* focus cycle root will be traversed instead.
*
* @return whether this ContainerOrderFocusTraversalPolicy transfers focus
* down-cycle implicitly
* @see #setImplicitDownCycleTraversal
* @see #getFirstComponent
*/
public boolean getImplicitDownCycleTraversal() {
return implicitDownCycleTraversal;
}
/**
* Determines whether a Component is an acceptable choice as the new
* focus owner. By default, this method will accept a Component if and
* only if it is visible, displayable, enabled, and focusable.
*
* @param aComponent the Component whose fitness as a focus owner is to
* be tested
* @return <code>true</code> if aComponent is visible, displayable,
* enabled, and focusable; <code>false</code> otherwise
*/
protected 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;
}
}
class MutableBoolean {
boolean value = false;
}
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