| /* | |
| * Copyright (c) 2000, 2025, 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 java.awt; | |
| import java.io.Serial; | |
| import java.util.ArrayList; | |
| import java.util.List; | |
| import sun.util.logging.PlatformLogger; | |
| /** | |
| * 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()}. 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} method. | |
| * <p> | |
| * By default, methods of this class will return a Component only if it is | |
| * visible, displayable, enabled, and focusable. Subclasses can modify this | |
| * behavior by overriding the {@code accept} 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 | |
| * | |
| * @see Container#getComponents | |
| * @since 1.4 | |
| */ | |
| public class ContainerOrderFocusTraversalPolicy extends FocusTraversalPolicy | |
| implements java.io.Serializable | |
| { | |
| private static final PlatformLogger log = PlatformLogger.getLogger("java.awt.ContainerOrderFocusTraversalPolicy"); | |
| /** | |
| * @serial This constant is used when the forward focus traversal order is active. | |
| */ | |
| private final int FORWARD_TRAVERSAL = 0; | |
| /** | |
| * @serial This constant is used when the backward focus traversal order is active. | |
| */ | |
| private final int BACKWARD_TRAVERSAL = 1; | |
| /** | |
| * Use serialVersionUID from JDK 1.4 for interoperability. | |
| */ | |
| @Serial | |
| private static final long serialVersionUID = 486933713763926351L; | |
| /** | |
| * @serial Whether this {@code ContainerOrderFocusTraversalPolicy} transfers focus | |
| * down-cycle implicitly. | |
| */ | |
| private boolean implicitDownCycleTraversal = true; | |
| /** | |
| * Used by getComponentAfter and getComponentBefore for efficiency. In | |
| * order to maintain compliance with the specification of | |
| * FocusTraversalPolicy, if traversal wraps, we should invoke | |
| * getFirstComponent or getLastComponent. These methods may be overridden in | |
| * subclasses to behave in a non-generic way. However, in the generic case, | |
| * these methods will simply return the first or last Components of the | |
| * sorted list, respectively. Since getComponentAfter and | |
| * getComponentBefore have already built the list before determining | |
| * that they need to invoke getFirstComponent or getLastComponent, the | |
| * list should be reused if possible. | |
| */ | |
| private transient Container cachedRoot; | |
| private transient List<Component> cachedCycle; | |
| /** | |
| * Constructs a {@code ContainerOrderFocusTraversalPolicy}. | |
| */ | |
| public ContainerOrderFocusTraversalPolicy() {} | |
| /* | |
| * We suppose to use getFocusTraversalCycle & getComponentIndex methods in order | |
| * to divide the policy into two parts: | |
| * 1) Making the focus traversal cycle. | |
| * 2) Traversing the cycle. | |
| * The 1st point assumes producing a list of components representing the focus | |
| * traversal cycle. The two methods mentioned above should implement this logic. | |
| * The 2nd point assumes implementing the common concepts of operating on the | |
| * cycle: traversing back and forth, retrieving the initial/default/first/last | |
| * component. These concepts are described in the AWT Focus Spec and they are | |
| * applied to the FocusTraversalPolicy in general. | |
| * Thus, a descendant of this policy may wish to not reimplement the logic of | |
| * the 2nd point but just override the implementation of the 1st one. | |
| * A striking example of such a descendant is the javax.swing.SortingFocusTraversalPolicy. | |
| */ | |
| /*protected*/ private List<Component> getFocusTraversalCycle(Container aContainer) { | |
| List<Component> cycle = new ArrayList<Component>(); | |
| enumerateCycle(aContainer, cycle); | |
| return cycle; | |
| } | |
| /*protected*/ private int getComponentIndex(List<Component> cycle, Component aComponent) { | |
| return cycle.indexOf(aComponent); | |
| } | |
| private void enumerateCycle(Container container, List<Component> cycle) { | |
| if (!(container.isVisible() && container.isDisplayable())) { | |
| return; | |
| } | |
| cycle.add(container); | |
| Component[] components = container.getComponents(); | |
| for (int i = 0; i < components.length; i++) { | |
| Component comp = components[i]; | |
| if (comp instanceof Container) { | |
| Container cont = (Container)comp; | |
| if (!cont.isFocusCycleRoot() && !cont.isFocusTraversalPolicyProvider()) { | |
| enumerateCycle(cont, cycle); | |
| continue; | |
| } | |
| } | |
| cycle.add(comp); | |
| } | |
| } | |
| private Container getTopmostProvider(Container focusCycleRoot, Component aComponent) { | |
| Container aCont = aComponent.getParent(); | |
| Container ftp = null; | |
| while (aCont != focusCycleRoot && aCont != null) { | |
| if (aCont.isFocusTraversalPolicyProvider()) { | |
| ftp = aCont; | |
| } | |
| aCont = aCont.getParent(); | |
| } | |
| if (aCont == null) { | |
| return null; | |
| } | |
| return ftp; | |
| } | |
| /* | |
| * Checks if a new focus cycle takes place and returns a Component to traverse focus to. | |
| * @param comp a possible focus cycle root or policy provider | |
| * @param traversalDirection the direction of the traversal | |
| * @return a Component to traverse focus to if {@code comp} is a root or provider | |
| * and implicit down-cycle is set, otherwise {@code null} | |
| */ | |
| private Component getComponentDownCycle(Component comp, int traversalDirection) { | |
| Component retComp = null; | |
| if (comp instanceof Container) { | |
| Container cont = (Container)comp; | |
| if (cont.isFocusCycleRoot()) { | |
| if (getImplicitDownCycleTraversal()) { | |
| retComp = cont.getFocusTraversalPolicy().getDefaultComponent(cont); | |
| if (retComp != null && log.isLoggable(PlatformLogger.Level.FINE)) { | |
| log.fine("### Transferred focus down-cycle to " + retComp + | |
| " in the focus cycle root " + cont); | |
| } | |
| } else { | |
| return null; | |
| } | |
| } else if (cont.isFocusTraversalPolicyProvider()) { | |
| retComp = (traversalDirection == FORWARD_TRAVERSAL ? | |
| cont.getFocusTraversalPolicy().getDefaultComponent(cont) : | |
| cont.getFocusTraversalPolicy().getLastComponent(cont)); | |
| if (retComp != null && log.isLoggable(PlatformLogger.Level.FINE)) { | |
| log.fine("### Transferred focus to " + retComp + " in the FTP provider " + cont); | |
| } | |
| } | |
| } | |
| return retComp; | |
| } | |
| /** | |
| * 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} 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(PlatformLogger.Level.FINE)) { | |
| log.fine("### Searching in " + aContainer + " for component after " + 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()) { | |
| if (!(aContainer.isVisible() && aContainer.isDisplayable())) { | |
| return null; | |
| } | |
| // Before all the checks below we first see if it's an FTP provider or a focus cycle root. | |
| // If it's the case just go down cycle (if it's set to "implicit"). | |
| Component comp = getComponentDownCycle(aComponent, FORWARD_TRAVERSAL); | |
| // Check if aComponent is focus-cycle-root's default Component, i.e. | |
| // focus cycle root & focus-cycle-root's default Component is same. | |
| if (comp != null && comp != aComponent) { | |
| return comp; | |
| } | |
| // See if the component is inside of policy provider. | |
| Container provider = getTopmostProvider(aContainer, aComponent); | |
| if (provider != null) { | |
| if (log.isLoggable(PlatformLogger.Level.FINE)) { | |
| log.fine("### Asking FTP " + provider + " for component after " + aComponent); | |
| } | |
| // FTP knows how to find component after the given. We don't. | |
| FocusTraversalPolicy policy = provider.getFocusTraversalPolicy(); | |
| Component afterComp = policy.getComponentAfter(provider, aComponent); | |
| // Null result means that we overstepped the limit of the FTP's cycle. | |
| // In that case we must quit the cycle, otherwise return the component found. | |
| if (afterComp != null) { | |
| if (log.isLoggable(PlatformLogger.Level.FINE)) { | |
| log.fine("### FTP returned " + afterComp); | |
| } | |
| return afterComp; | |
| } | |
| aComponent = provider; | |
| } | |
| List<Component> cycle = getFocusTraversalCycle(aContainer); | |
| if (log.isLoggable(PlatformLogger.Level.FINE)) { | |
| log.fine("### Cycle is " + cycle + ", component is " + aComponent); | |
| } | |
| int index = getComponentIndex(cycle, aComponent); | |
| if (index < 0) { | |
| if (log.isLoggable(PlatformLogger.Level.FINE)) { | |
| log.fine("### Didn't find component " + aComponent + " in a cycle " + aContainer); | |
| } | |
| return getFirstComponent(aContainer); | |
| } | |
| for (index++; index < cycle.size(); index++) { | |
| comp = cycle.get(index); | |
| if (accept(comp)) { | |
| return comp; | |
| } else if ((comp = getComponentDownCycle(comp, FORWARD_TRAVERSAL)) != null) { | |
| return comp; | |
| } | |
| } | |
| if (aContainer.isFocusCycleRoot()) { | |
| this.cachedRoot = aContainer; | |
| this.cachedCycle = cycle; | |
| comp = getFirstComponent(aContainer); | |
| this.cachedRoot = null; | |
| this.cachedCycle = null; | |
| return comp; | |
| } | |
| } | |
| 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()) { | |
| if (!(aContainer.isVisible() && aContainer.isDisplayable())) { | |
| return null; | |
| } | |
| // See if the component is inside of policy provider. | |
| Container provider = getTopmostProvider(aContainer, aComponent); | |
| if (provider != null) { | |
| if (log.isLoggable(PlatformLogger.Level.FINE)) { | |
| log.fine("### Asking FTP " + provider + " for component after " + aComponent); | |
| } | |
| // FTP knows how to find component after the given. We don't. | |
| FocusTraversalPolicy policy = provider.getFocusTraversalPolicy(); | |
| Component beforeComp = policy.getComponentBefore(provider, aComponent); | |
| // Null result means that we overstepped the limit of the FTP's cycle. | |
| // In that case we must quit the cycle, otherwise return the component found. | |
| if (beforeComp != null) { | |
| if (log.isLoggable(PlatformLogger.Level.FINE)) { | |
| log.fine("### FTP returned " + beforeComp); | |
| } | |
| return beforeComp; | |
| } | |
| aComponent = provider; | |
| // If the provider is traversable it's returned. | |
| if (accept(aComponent)) { | |
| return aComponent; | |
| } | |
| } | |
| List<Component> cycle = getFocusTraversalCycle(aContainer); | |
| if (log.isLoggable(PlatformLogger.Level.FINE)) { | |
| log.fine("### Cycle is " + cycle + ", component is " + aComponent); | |
| } | |
| int index = getComponentIndex(cycle, aComponent); | |
| if (index < 0) { | |
| if (log.isLoggable(PlatformLogger.Level.FINE)) { | |
| log.fine("### Didn't find component " + aComponent + " in a cycle " + aContainer); | |
| } | |
| return getLastComponent(aContainer); | |
| } | |
| Component comp = null; | |
| Component tryComp = null; | |
| for (index--; index>=0; index--) { | |
| comp = cycle.get(index); | |
| if (comp != aContainer && (tryComp = getComponentDownCycle(comp, BACKWARD_TRAVERSAL)) != null) { | |
| return tryComp; | |
| } else if (accept(comp)) { | |
| return comp; | |
| } | |
| } | |
| if (aContainer.isFocusCycleRoot()) { | |
| this.cachedRoot = aContainer; | |
| this.cachedCycle = cycle; | |
| comp = getLastComponent(aContainer); | |
| this.cachedRoot = null; | |
| this.cachedCycle = null; | |
| return comp; | |
| } | |
| } | |
| 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) { | |
| List<Component> cycle; | |
| if (log.isLoggable(PlatformLogger.Level.FINE)) { | |
| log.fine("### Getting first component in " + aContainer); | |
| } | |
| if (aContainer == null) { | |
| throw new IllegalArgumentException("aContainer cannot be null"); | |
| } | |
| synchronized(aContainer.getTreeLock()) { | |
| if (!(aContainer.isVisible() && aContainer.isDisplayable())) { | |
| return null; | |
| } | |
| if (this.cachedRoot == aContainer) { | |
| cycle = this.cachedCycle; | |
| } else { | |
| cycle = getFocusTraversalCycle(aContainer); | |
| } | |
| if (cycle.size() == 0) { | |
| if (log.isLoggable(PlatformLogger.Level.FINE)) { | |
| log.fine("### Cycle is empty"); | |
| } | |
| return null; | |
| } | |
| if (log.isLoggable(PlatformLogger.Level.FINE)) { | |
| log.fine("### Cycle is " + cycle); | |
| } | |
| for (Component comp : cycle) { | |
| if (accept(comp)) { | |
| return comp; | |
| } else if (comp != aContainer && | |
| (comp = getComponentDownCycle(comp, FORWARD_TRAVERSAL)) != null) | |
| { | |
| 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) { | |
| List<Component> cycle; | |
| if (log.isLoggable(PlatformLogger.Level.FINE)) { | |
| log.fine("### Getting last component in " + aContainer); | |
| } | |
| if (aContainer == null) { | |
| throw new IllegalArgumentException("aContainer cannot be null"); | |
| } | |
| synchronized(aContainer.getTreeLock()) { | |
| if (!(aContainer.isVisible() && aContainer.isDisplayable())) { | |
| return null; | |
| } | |
| if (this.cachedRoot == aContainer) { | |
| cycle = this.cachedCycle; | |
| } else { | |
| cycle = getFocusTraversalCycle(aContainer); | |
| } | |
| if (cycle.size() == 0) { | |
| if (log.isLoggable(PlatformLogger.Level.FINE)) { | |
| log.fine("### Cycle is empty"); | |
| } | |
| return null; | |
| } | |
| if (log.isLoggable(PlatformLogger.Level.FINE)) { | |
| log.fine("### Cycle is " + cycle); | |
| } | |
| for (int i= cycle.size() - 1; i >= 0; i--) { | |
| Component comp = cycle.get(i); | |
| if (accept(comp)) { | |
| return comp; | |
| } else if (comp instanceof Container && comp != aContainer) { | |
| Container cont = (Container)comp; | |
| if (cont.isFocusTraversalPolicyProvider()) { | |
| Component retComp = cont.getFocusTraversalPolicy().getLastComponent(cont); | |
| if (retComp != null) { | |
| return retComp; | |
| } | |
| } | |
| } | |
| } | |
| } | |
| 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}. | |
| * | |
| * @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}, 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}, | |
| * 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}. | |
| * | |
| * @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}, 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}, | |
| * 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} if aComponent is visible, displayable, | |
| * enabled, and focusable; {@code false} otherwise | |
| */ | |
| protected boolean accept(Component aComponent) { | |
| if (!aComponent.canBeFocusOwner()) { | |
| 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; | |
| } | |
| } |