jdk/src/share/classes/javax/swing/SortingFocusTraversalPolicy.java
changeset 2 90ce3da70b43
child 1301 15e81207e1f2
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/jdk/src/share/classes/javax/swing/SortingFocusTraversalPolicy.java	Sat Dec 01 00:00:00 2007 +0000
@@ -0,0 +1,599 @@
+/*
+ * Copyright 2000-2007 Sun Microsystems, Inc.  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.  Sun designates this
+ * particular file as subject to the "Classpath" exception as provided
+ * by Sun 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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
+ * CA 95054 USA or visit www.sun.com if you need additional information or
+ * have any questions.
+ */
+package javax.swing;
+
+import java.awt.Component;
+import java.awt.Container;
+import java.awt.Window;
+import java.util.*;
+import java.awt.FocusTraversalPolicy;
+import java.util.logging.*;
+
+/**
+ * A FocusTraversalPolicy that determines traversal order by sorting the
+ * Components of a focus traversal cycle based on a given Comparator. Portions
+ * of the Component hierarchy that are not visible and displayable will not be
+ * included.
+ * <p>
+ * By default, SortingFocusTraversalPolicy 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
+ * <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="../../java/awt/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 java.util.Comparator
+ * @since 1.4
+ */
+public class SortingFocusTraversalPolicy
+    extends InternalFrameFocusTraversalPolicy
+{
+    private Comparator<? super Component> comparator;
+    private boolean implicitDownCycleTraversal = true;
+
+    private Logger log = Logger.getLogger("javax.swing.SortingFocusTraversalPolicy");
+
+    /**
+     * 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 overriden 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 sorted list before determining
+     * that they need to invoke getFirstComponent or getLastComponent, the
+     * sorted list should be reused if possible.
+     */
+    transient private Container cachedRoot;
+    transient private List cachedCycle;
+
+    // Delegate our fitness test to ContainerOrder so that we only have to
+    // code the algorithm once.
+    private static final SwingContainerOrderFocusTraversalPolicy
+        fitnessTestPolicy = new SwingContainerOrderFocusTraversalPolicy();
+
+    final private int FORWARD_TRAVERSAL = 0;
+    final private int BACKWARD_TRAVERSAL = 1;
+
+    /**
+     * Constructs a SortingFocusTraversalPolicy without a Comparator.
+     * Subclasses must set the Comparator using <code>setComparator</code>
+     * before installing this FocusTraversalPolicy on a focus cycle root or
+     * KeyboardFocusManager.
+     */
+    protected SortingFocusTraversalPolicy() {
+    }
+
+    /**
+     * Constructs a SortingFocusTraversalPolicy with the specified Comparator.
+     */
+    public SortingFocusTraversalPolicy(Comparator<? super Component> comparator) {
+        this.comparator = comparator;
+    }
+
+    private List<Component> getFocusTraversalCycle(Container aContainer) {
+        List<Component> cycle = new ArrayList<Component>();
+        enumerateAndSortCycle(aContainer, cycle);
+        return cycle;
+    }
+    private int getComponentIndex(List<Component> cycle, Component aComponent) {
+        int index = 0;
+        try {
+            index = Collections.binarySearch(cycle, aComponent, comparator);
+        } catch (ClassCastException e) {
+            if (log.isLoggable(Level.FINE)) {
+                log.log(Level.FINE, "### During the binary search for " + aComponent + " the exception occured: ", e);
+            }
+            return -1;
+        }
+        if (index < 0) {
+            // Fix for 5070991.
+            // A workaround for a transitivity problem caused by ROW_TOLERANCE,
+            // because of that the component may be missed in the binary search.
+            // Try to search it again directly.
+            index = cycle.indexOf(aComponent);
+        }
+        return index;
+    }
+
+    private void enumerateAndSortCycle(Container focusCycleRoot, List cycle) {
+        if (focusCycleRoot.isShowing()) {
+            enumerateCycle(focusCycleRoot, cycle);
+            Collections.sort(cycle, comparator);
+        }
+    }
+
+    private void enumerateCycle(Container container, List 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() &&
+                    !((cont instanceof JComponent) && ((JComponent)cont).isManagingFocus()))
+                {
+                    enumerateCycle(cont, cycle);
+                    continue;
+                }
+            }
+            cycle.add(comp);
+        }
+    }
+
+    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(Level.FINE)) {
+                        log.fine("### Transfered 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(Level.FINE)) {
+                    log.fine("### Transfered 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, SortingFocusTraversalPolicy 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
+     * <code>setImplicitDownCycleTraversal</code> method.
+     * <p>
+     * If aContainer is <a href="../../java/awt/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 a 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("### 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");
+        }
+
+        // Before all the ckecks 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);
+        if (comp != null) {
+            return comp;
+        }
+
+        // See if the component is inside of policy provider.
+        Container provider = getTopmostProvider(aContainer, aComponent);
+        if (provider != null) {
+            if (log.isLoggable(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(Level.FINE)) log.fine("### FTP returned " + afterComp);
+                return afterComp;
+            }
+            aComponent = provider;
+        }
+
+        List<Component> cycle = getFocusTraversalCycle(aContainer);
+
+        if (log.isLoggable(Level.FINE)) log.fine("### Cycle is " + cycle + ", component is " + aComponent);
+
+        int index = getComponentIndex(cycle, aComponent);
+
+        if (index < 0) {
+            if (log.isLoggable(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 focus traversal policy provider.
+     * <p>
+     * By default, SortingFocusTraversalPolicy 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
+     * <code>setImplicitDownCycleTraversal</code> method.
+     * <p>
+     * If aContainer is <a href="../../java/awt/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 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");
+        }
+        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");
+        }
+
+        // See if the component is inside of policy provider.
+        Container provider = getTopmostProvider(aContainer, aComponent);
+        if (provider != null) {
+            if (log.isLoggable(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(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(Level.FINE)) log.fine("### Cycle is " + cycle + ", component is " + aComponent);
+
+        int index = getComponentIndex(cycle, aComponent);
+
+        if (index < 0) {
+            if (log.isLoggable(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 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) {
+        List<Component> cycle;
+
+        if (log.isLoggable(Level.FINE)) log.fine("### Getting first component in " + aContainer);
+        if (aContainer == null) {
+            throw new IllegalArgumentException("aContainer cannot be null");
+        }
+
+        if (this.cachedRoot == aContainer) {
+            cycle = this.cachedCycle;
+        } else {
+            cycle = getFocusTraversalCycle(aContainer);
+        }
+
+        if (cycle.size() == 0) {
+            if (log.isLoggable(Level.FINE)) log.fine("### Cycle is empty");
+            return null;
+        }
+        if (log.isLoggable(Level.FINE)) log.fine("### Cycle is " + cycle);
+
+        for (int i = 0; i < cycle.size(); 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()) {
+                    return cont.getFocusTraversalPolicy().getDefaultComponent(cont);
+                }
+            }
+        }
+        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 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) {
+        List<Component> cycle;
+        if (log.isLoggable(Level.FINE)) log.fine("### Getting last component in " + aContainer);
+
+        if (aContainer == null) {
+            throw new IllegalArgumentException("aContainer cannot be null");
+        }
+
+        if (this.cachedRoot == aContainer) {
+            cycle = this.cachedCycle;
+        } else {
+            cycle = getFocusTraversalCycle(aContainer);
+        }
+
+        if (cycle.size() == 0) {
+            if (log.isLoggable(Level.FINE)) log.fine("### Cycle is empty");
+            return null;
+        }
+        if (log.isLoggable(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()) {
+                    return cont.getFocusTraversalPolicy().getLastComponent(cont);
+                }
+            }
+        }
+        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 a focus cycle root of aComponent or a 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 SortingFocusTraversalPolicy transfers focus down-cycle
+     * implicitly. If <code>true</code>, during normal 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
+     *        SortingFocusTraversalPolicy transfers focus down-cycle implicitly
+     * @see #getImplicitDownCycleTraversal
+     * @see #getFirstComponent
+     */
+    public void setImplicitDownCycleTraversal(boolean implicitDownCycleTraversal) {
+        this.implicitDownCycleTraversal = implicitDownCycleTraversal;
+    }
+
+    /**
+     * Returns whether this SortingFocusTraversalPolicy transfers focus down-
+     * cycle implicitly. If <code>true</code>, during normal 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 SortingFocusTraversalPolicy transfers focus down-
+     *         cycle implicitly
+     * @see #setImplicitDownCycleTraversal
+     * @see #getFirstComponent
+     */
+    public boolean getImplicitDownCycleTraversal() {
+        return implicitDownCycleTraversal;
+    }
+
+    /**
+     * Sets the Comparator which will be used to sort the Components in a
+     * focus traversal cycle.
+     *
+     * @param comparator the Comparator which will be used for sorting
+     */
+    protected void setComparator(Comparator<? super Component> comparator) {
+        this.comparator = comparator;
+    }
+
+    /**
+     * Returns the Comparator which will be used to sort the Components in a
+     * focus traversal cycle.
+     *
+     * @return the Comparator which will be used for sorting
+     */
+    protected Comparator<? super Component> getComparator() {
+        return comparator;
+    }
+
+    /**
+     * 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) {
+        return fitnessTestPolicy.accept(aComponent);
+    }
+}
+
+// Create our own subclass and change accept to public so that we can call
+// accept.
+class SwingContainerOrderFocusTraversalPolicy
+    extends java.awt.ContainerOrderFocusTraversalPolicy
+{
+    public boolean accept(Component aComponent) {
+        return super.accept(aComponent);
+    }
+}