2362N/A * Copyright (c) 2000, 2005, Oracle and/or its affiliates. All rights reserved. 0N/A * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. 0N/A * This code is free software; you can redistribute it and/or modify it 0N/A * under the terms of the GNU General Public License version 2 only, as 2362N/A * published by the Free Software Foundation. Oracle designates this 0N/A * particular file as subject to the "Classpath" exception as provided 2362N/A * by Oracle in the LICENSE file that accompanied this code. 0N/A * This code is distributed in the hope that it will be useful, but WITHOUT 0N/A * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 0N/A * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 0N/A * version 2 for more details (a copy is included in the LICENSE file that 0N/A * accompanied this code). 0N/A * You should have received a copy of the GNU General Public License version 0N/A * 2 along with this work; if not, write to the Free Software Foundation, 0N/A * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. 2362N/A * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA 2362N/A * or visit www.oracle.com if you need additional information or have any 0N/A * A FocusTraversalPolicy defines the order in which Components with a 0N/A * particular focus cycle root are traversed. Instances can apply the policy to 0N/A * arbitrary focus cycle roots, allowing themselves to be shared across 0N/A * Containers. They do not need to be reinitialized when the focus cycle roots 0N/A * of a Component hierarchy change. 0N/A * The core responsibility of a FocusTraversalPolicy is to provide algorithms 0N/A * determining the next and previous Components to focus when traversing 0N/A * forward or backward in a UI. Each FocusTraversalPolicy must also provide 0N/A * algorithms for determining the first, last, and default Components in a 0N/A * traversal cycle. First and last Components are used when normal forward and 0N/A * backward traversal, respectively, wraps. The default Component is the first 0N/A * to receive focus when traversing down into a new focus traversal cycle. 0N/A * A FocusTraversalPolicy can optionally provide an algorithm for determining 0N/A * a Window's initial Component. The initial Component is the first to receive 0N/A * focus when a Window is first made visible. 0N/A * FocusTraversalPolicy takes into account <a 0N/A * if a focus traversal policy provider is encountered, its focus traversal 0N/A * policy is used to perform the search operation. 0N/A * How to Use the Focus Subsystem</a>, 0N/A * a section in <em>The Java Tutorial</em>, and the 0N/A * for more information. 0N/A * @author David Mendenhall 0N/A * @see Container#setFocusTraversalPolicy 0N/A * @see Container#getFocusTraversalPolicy 0N/A * @see Container#setFocusCycleRoot 0N/A * @see Container#isFocusCycleRoot 0N/A * @see Container#setFocusTraversalPolicyProvider 0N/A * @see Container#isFocusTraversalPolicyProvider 0N/A * @see KeyboardFocusManager#setDefaultFocusTraversalPolicy 0N/A * @see KeyboardFocusManager#getDefaultFocusTraversalPolicy 0N/A * Returns the Component that should receive the focus after aComponent. 0N/A * aContainer must be a focus cycle root of aComponent or a focus traversal 0N/A * @param aContainer a focus cycle root of aComponent or focus traversal 0N/A * @param aComponent a (possibly indirect) child of aContainer, or 0N/A * @return the Component that should receive the focus after aComponent, or 0N/A * null if no suitable Component can be found 0N/A * @throws IllegalArgumentException if aContainer is not a focus cycle 0N/A * root of aComponent or a focus traversal policy provider, or if 0N/A * either aContainer or aComponent is null 0N/A * Returns the Component that should receive the focus before aComponent. 0N/A * aContainer must be a focus cycle root of aComponent or a focus traversal 0N/A * @param aContainer a focus cycle root of aComponent or focus traversal 0N/A * @param aComponent a (possibly indirect) child of aContainer, or 0N/A * @return the Component that should receive the focus before aComponent, 0N/A * or null if no suitable Component can be found 0N/A * @throws IllegalArgumentException if aContainer is not a focus cycle 0N/A * root of aComponent or a focus traversal policy provider, or if 0N/A * either aContainer or aComponent is null 0N/A * Returns the first Component in the traversal cycle. This method is used 0N/A * to determine the next Component to focus when traversal wraps in the 0N/A * forward direction. 0N/A * @param aContainer the focus cycle root or focus traversal policy provider 0N/A * whose first Component is to be returned 0N/A * @return the first Component in the traversal cycle of aContainer, 0N/A * or null if no suitable Component can be found 0N/A * @throws IllegalArgumentException if aContainer is null 0N/A * Returns the last Component in the traversal cycle. This method is used 0N/A * to determine the next Component to focus when traversal wraps in the 0N/A * reverse direction. 0N/A * @param aContainer the focus cycle root or focus traversal policy 0N/A * provider whose last Component is to be returned 0N/A * @return the last Component in the traversal cycle of aContainer, 0N/A * or null if no suitable Component can be found 0N/A * @throws IllegalArgumentException if aContainer is null 0N/A * Returns the default Component to focus. This Component will be the first 0N/A * to receive focus when traversing down into a new focus traversal cycle 0N/A * rooted at aContainer. 0N/A * @param aContainer the focus cycle root or focus traversal policy 0N/A * provider whose default Component is to be returned 0N/A * @return the default Component in the traversal cycle of aContainer, 0N/A * or null if no suitable Component can be found 0N/A * @throws IllegalArgumentException if aContainer is null 0N/A * Returns the Component that should receive the focus when a Window is 0N/A * made visible for the first time. Once the Window has been made visible 0N/A * by a call to <code>show()</code> or <code>setVisible(true)</code>, the 0N/A * initial Component will not be used again. Instead, if the Window loses 0N/A * and subsequently regains focus, or is made invisible or undisplayable 0N/A * and subsequently made visible and displayable, the Window's most 0N/A * recently focused Component will become the focus owner. The default 0N/A * implementation of this method returns the default Component. 0N/A * @param window the Window whose initial Component is to be returned 0N/A * @return the Component that should receive the focus when window is made 0N/A * visible for the first time, or null if no suitable Component can 0N/A * @see #getDefaultComponent 0N/A * @see Window#getMostRecentFocusOwner 0N/A * @throws IllegalArgumentException if window is null