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From-SVN: r102074

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diff --git a/libjava/classpath/java/awt/ContainerOrderFocusTraversalPolicy.java b/libjava/classpath/java/awt/ContainerOrderFocusTraversalPolicy.java
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+/* ContainerOrderFocusTraversalPolicy.java -- 
+   Copyright (C) 2002, 2005  Free Software Foundation, Inc.
+
+This file is part of GNU Classpath.
+
+GNU Classpath is free software; you can redistribute it and/or modify
+it under the terms of the GNU General Public License as published by
+the Free Software Foundation; either version 2, or (at your option)
+any later version.
+
+GNU Classpath 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 for more details.
+
+You should have received a copy of the GNU General Public License
+along with GNU Classpath; see the file COPYING.  If not, write to the
+Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
+02110-1301 USA.
+
+Linking this library statically or dynamically with other modules is
+making a combined work based on this library.  Thus, the terms and
+conditions of the GNU General Public License cover the whole
+combination.
+
+As a special exception, the copyright holders of this library give you
+permission to link this library with independent modules to produce an
+executable, regardless of the license terms of these independent
+modules, and to copy and distribute the resulting executable under
+terms of your choice, provided that you also meet, for each linked
+independent module, the terms and conditions of the license of that
+module.  An independent module is a module which is not derived from
+or based on this library.  If you modify this library, you may extend
+this exception to your version of the library, but you are not
+obligated to do so.  If you do not wish to do so, delete this
+exception statement from your version. */
+
+
+package java.awt;
+
+import java.io.Serializable;
+
+/**
+ * ContainerOrderFocusTraversalPolicy defines a focus traversal order
+ * based on the order in which Components were packed in a Container.
+ * This policy performs a pre-order traversal of the Component
+ * hierarchy starting from a given focus cycle root.  Portions of the
+ * hierarchy that are not visible and displayable are skipped.
+ *
+ * By default, this policy transfers focus down-cycle implicitly.
+ * That is, if a forward traversal is requested on a focus cycle root
+ * and the focus cycle root has focusable children, the focus will
+ * automatically be transfered down to the lower focus cycle.
+ *
+ * The default implementation of accept accepts only Components that
+ * are visible, displayable, enabled and focusable.  Derived classes
+ * can override these acceptance criteria by overriding accept.
+ *
+ * @author Michael Koch
+ * @author Thomas Fitzsimmons (fitzsim@redhat.com)
+ * @since 1.4
+ */
+public class ContainerOrderFocusTraversalPolicy extends FocusTraversalPolicy
+  implements Serializable
+{
+  /**
+   * Compatible to JDK 1.4+
+   */
+  static final long serialVersionUID = 486933713763926351L;
+
+  /**
+   * True if implicit down cycling is enabled.
+   */
+  private boolean implicitDownCycleTraversal = true;
+
+  /**
+   * Creates the <code>ContainerOrderFocusTraversalPolicy</code> object.
+   */
+  public ContainerOrderFocusTraversalPolicy ()
+  {
+    // Nothing to do here
+  }
+
+  /**
+   * Returns the Component that should receive the focus after current.
+   * root must be a focus cycle root of current.
+   *
+   * @param root a focus cycle root of current
+   * @param current a (possibly indirect) child of root, or root itself
+   *
+   * @return the next Component in the focus traversal order for root,
+   * or null if no acceptable Component exists.
+   *
+   * @exception IllegalArgumentException If root is not a focus cycle
+   * root of current, or if either root or current is null.
+   */
+  public Component getComponentAfter (Container root, Component current)
+  {
+    if (root == null)
+      throw new IllegalArgumentException ("focus cycle root is null");
+    if (current == null)
+      throw new IllegalArgumentException ("current component is null");
+
+    if (!root.isFocusCycleRoot ())
+      throw new IllegalArgumentException ("root is not a focus cycle root");
+
+    Container ancestor = current.getFocusCycleRootAncestor ();
+    Container prevAncestor = ancestor;
+    while (ancestor != root)
+      {
+	ancestor = current.getFocusCycleRootAncestor ();
+	if (ancestor == prevAncestor)
+	  {
+	    // We've reached the top focus cycle root ancestor.  Check
+	    // if it is root.
+	    if (ancestor != root)
+	      throw new IllegalArgumentException ("the given container is not"
+						  + " a focus cycle root of the"
+						  + " current component");
+	    else
+	      break;
+	  }
+	prevAncestor = ancestor;
+      }
+
+    // FIXME: is this the right thing to do here? It moves the context
+    // for traversal up one focus traversal cycle.  We'll need a test
+    // for this.
+    if ((Component) root == current)
+      root = current.getFocusCycleRootAncestor ();
+
+    // Check if we've reached the top of the component hierarchy.  If
+    // so then we want to loop around to the first component in the
+    // focus traversal cycle.
+    if (current instanceof Window)
+      return getFirstComponent ((Container) current);
+
+    Container parent = current.getParent ();
+
+    synchronized (parent.getTreeLock ())
+      {
+        Component[] components = parent.getComponents ();
+        int componentIndex = 0;
+        int numComponents = parent.getComponentCount ();
+
+        // Find component's index.
+        for (int i = 0; i < numComponents; i++)
+          {
+            if (components[i] == current)
+              componentIndex = i;
+          }
+
+        // Search forward for the next acceptable component.
+        for (int i = componentIndex + 1; i < numComponents; i++)
+          {
+            if (accept (components[i]))
+              return components[i];
+
+            if (components[i] instanceof Container)
+              {
+                Component result = getFirstComponent ((Container) components[i]);
+
+                if (result != null
+                    && implicitDownCycleTraversal)
+                  return result;
+              }
+          }
+
+        // No focusable components after current in its Container.  So go
+        // to the next Component after current's Container (parent).
+        Component result = getComponentAfter (root, parent);
+
+        return result;
+      }
+  }
+
+  /**
+   * Returns the Component that should receive the focus before
+   * <code>current</code>.  <code>root</code> must be a focus cycle
+   * root of current.
+   *
+   * @param root a focus cycle root of current
+   * @param current a (possibly indirect) child of root, or root itself
+   *
+   * @return the previous Component in the focus traversal order for
+   * root, or null if no acceptable Component exists.
+   *
+   * @exception IllegalArgumentException If root is not a focus cycle
+   * root of current, or if either root or current is null.
+   */
+  public Component getComponentBefore (Container root, Component current)
+  {
+    if (root == null)
+      throw new IllegalArgumentException ("focus cycle root is null");
+    if (current == null)
+      throw new IllegalArgumentException ("current component is null");
+
+    if (!root.isFocusCycleRoot ())
+      throw new IllegalArgumentException ("root is not a focus cycle root");
+
+    Container ancestor = current.getFocusCycleRootAncestor ();
+    Container prevAncestor = ancestor;
+    while (ancestor != root)
+      {
+	ancestor = current.getFocusCycleRootAncestor ();
+	if (ancestor == prevAncestor)
+	  {
+	    // We've reached the top focus cycle root ancestor.  Check
+	    // if it is root.
+	    if (ancestor != root)
+	      throw new IllegalArgumentException ("the given container is not"
+						  + " a focus cycle root of the"
+						  + " current component");
+	    else
+	      break;
+	  }
+	prevAncestor = ancestor;
+      }
+
+    // FIXME: is this the right thing to do here? It moves the context
+    // for traversal up one focus traversal cycle.  We'll need a test
+    // for this.
+    if ((Component) root == current)
+      root = current.getFocusCycleRootAncestor ();
+
+    // Check if we've reached the top of the component hierarchy.  If
+    // so then we want to loop around to the last component in the
+    // focus traversal cycle.
+    if (current instanceof Window)
+      return getLastComponent ((Container) current);
+
+    Container parent = current.getParent ();
+
+    synchronized (parent.getTreeLock ())
+      {
+        Component[] components = parent.getComponents ();
+        int componentIndex = 0;
+        int numComponents = parent.getComponentCount ();
+
+        // Find component's index.
+        for (int i = 0; i < numComponents; i++)
+          {
+            if (components[i] == current)
+              componentIndex = i;
+          }
+
+        // Search backward for the next acceptable component.
+        for (int i = componentIndex - 1; i >= 0; i--)
+          {
+            if (accept (components[i]))
+              return components[i];
+
+            if (components[i] instanceof Container)
+              {
+                Component result = getLastComponent ((Container) components[i]);
+
+                if (result != null)
+                  return result;
+              }
+          }
+
+        // No focusable components before current in its Container.  So go
+        // to the previous Component before current's Container (parent).
+        Component result = getComponentBefore (root, parent);
+
+        return result;
+      }
+  }
+
+  /**
+   * Returns the first Component of root that should receive the focus.
+   *
+   * @param root a focus cycle root
+   *
+   * @return the first Component in the focus traversal order for
+   * root, or null if no acceptable Component exists.
+   *
+   * @exception IllegalArgumentException If root is null.
+   */
+  public Component getFirstComponent(Container root)
+  {
+    if (root == null)
+      throw new IllegalArgumentException ();
+
+    if (!root.isVisible ()
+        || !root.isDisplayable ())
+      return null;
+
+    if (accept (root))
+      return root;
+
+    Component[] componentArray = root.getComponents ();
+    
+    for (int i = 0; i < componentArray.length; i++)
+      {
+        Component component = componentArray [i];
+	
+	if (accept (component))
+	  return component;
+
+        if (component instanceof Container)
+          {
+            Component result = getFirstComponent ((Container) component);
+
+            if (result != null)
+              return result;
+          }
+      }
+
+    return null;
+  }
+
+  /**
+   * Returns the last Component of root that should receive the focus.
+   *
+   * @param root a focus cycle root
+   *
+   * @return the last Component in the focus traversal order for
+   * root, or null if no acceptable Component exists.
+   *
+   * @exception IllegalArgumentException If root is null.
+   */
+  public Component getLastComponent (Container root)
+  {
+    if (root == null)
+      throw new IllegalArgumentException ();
+
+    if (!root.isVisible ()
+        || !root.isDisplayable ())
+      return null;
+
+    if (accept (root))
+      return root;
+
+    Component[] componentArray = root.getComponents ();
+    
+    for (int i = componentArray.length - 1; i >= 0; i--)
+      {
+        Component component = componentArray [i];
+	
+	if (accept (component))
+	  return component;
+
+        if (component instanceof Container)
+          {
+            Component result = getLastComponent ((Container) component);
+
+            if (result != null)
+              return result;
+          }
+      }
+
+    return null;
+  }
+
+  /**
+   * Returns the default Component of root that should receive the focus.
+   *
+   * @param root a focus cycle root
+   *
+   * @return the default Component in the focus traversal order for
+   * root, or null if no acceptable Component exists.
+   *
+   * @exception IllegalArgumentException If root is null.
+   */
+  public Component getDefaultComponent (Container root)
+  {
+    return getFirstComponent (root);
+  }
+
+  /**
+   * Set whether or not implicit down cycling is enabled.  If it is,
+   * then initiating a forward focus traversal operation onto a focus
+   * cycle root, the focus will be implicitly transferred into the
+   * root container's focus cycle.
+   *
+   * @param value the setting for implicit down cycling
+   */
+  public void setImplicitDownCycleTraversal (boolean value)
+  {
+    implicitDownCycleTraversal = value;
+  }
+
+  /**
+   * Check whether or not implicit down cycling is enabled.  If it is,
+   * then initiating a forward focus traversal operation onto a focus
+   * cycle root, the focus will be implicitly transferred into the
+   * root container's focus cycle.
+   *
+   * @return true if the focus will be transferred down-cycle
+   * implicitly
+   */
+  public boolean getImplicitDownCycleTraversal ()
+  {
+    return implicitDownCycleTraversal;
+  }
+
+  /**
+   * Check whether the given Component is an acceptable target for the
+   * keyboard input focus.
+   *
+   * @param current the Component to check
+   *
+   * @return true if current is acceptable, false otherwise
+   */
+  protected boolean accept (Component current)
+  {
+    return (current.visible
+            && current.isDisplayable ()
+            && current.enabled
+            && current.focusable);
+  }
+}