001 /* FocusTraversalPolicy.java -- 002 Copyright (C) 2002 Free Software Foundation, Inc. 003 004 This file is part of GNU Classpath. 005 006 GNU Classpath is free software; you can redistribute it and/or modify 007 it under the terms of the GNU General Public License as published by 008 the Free Software Foundation; either version 2, or (at your option) 009 any later version. 010 011 GNU Classpath is distributed in the hope that it will be useful, but 012 WITHOUT ANY WARRANTY; without even the implied warranty of 013 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 014 General Public License for more details. 015 016 You should have received a copy of the GNU General Public License 017 along with GNU Classpath; see the file COPYING. If not, write to the 018 Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 019 02110-1301 USA. 020 021 Linking this library statically or dynamically with other modules is 022 making a combined work based on this library. Thus, the terms and 023 conditions of the GNU General Public License cover the whole 024 combination. 025 026 As a special exception, the copyright holders of this library give you 027 permission to link this library with independent modules to produce an 028 executable, regardless of the license terms of these independent 029 modules, and to copy and distribute the resulting executable under 030 terms of your choice, provided that you also meet, for each linked 031 independent module, the terms and conditions of the license of that 032 module. An independent module is a module which is not derived from 033 or based on this library. If you modify this library, you may extend 034 this exception to your version of the library, but you are not 035 obligated to do so. If you do not wish to do so, delete this 036 exception statement from your version. */ 037 038 039 package java.awt; 040 041 /** 042 * @since 1.4 043 */ 044 public abstract class FocusTraversalPolicy 045 { 046 /** 047 * Creates a <code>FocusTraversalPolicy</code> object. 048 */ 049 public FocusTraversalPolicy() 050 { 051 // Do nothing in here. 052 } 053 054 /** 055 * Returns the Component that should receive the focus after a Component. 056 * 057 * @exception IllegalArgumentException If root or current is null, 058 * or if root is not a focus cycle root of current. 059 */ 060 public abstract Component getComponentAfter(Container root, 061 Component current); 062 063 /** 064 * Returns the Component that should receive the focus before a Component. 065 * 066 * @exception IllegalArgumentException If root or current is null, 067 * or if root is not a focus cycle root of current. 068 */ 069 public abstract Component getComponentBefore(Container root, 070 Component current); 071 072 /** 073 * Returns the first Component in the traversal cycle. 074 * 075 * @exception IllegalArgumentException If root is null. 076 */ 077 public abstract Component getFirstComponent(Container root); 078 079 /** 080 * Returns the last Component in the traversal cycle. 081 * 082 * @exception IllegalArgumentException If root is null. 083 */ 084 public abstract Component getLastComponent(Container root); 085 086 /** 087 * Returns the default Component to focus. 088 * 089 * @exception IllegalArgumentException If root is null. 090 */ 091 public abstract Component getDefaultComponent(Container root); 092 093 /** 094 * Returns the Component that should receive the focus when a Window is made 095 * visible for the first time. 096 * 097 * @exception IllegalArgumentException If window is null. 098 */ 099 public Component getInitialComponent(Window window) 100 { 101 return getDefaultComponent(window); 102 } 103 } // class FocusTraversalPolicy