Source for java.awt.FocusTraversalPolicy

   1: /* FocusTraversalPolicy.java -- 
   2:    Copyright (C) 2002 Free Software Foundation, Inc.
   3: 
   4: This file is part of GNU Classpath.
   5: 
   6: GNU Classpath is free software; you can redistribute it and/or modify
   7: it under the terms of the GNU General Public License as published by
   8: the Free Software Foundation; either version 2, or (at your option)
   9: any later version.
  10: 
  11: GNU Classpath is distributed in the hope that it will be useful, but
  12: WITHOUT ANY WARRANTY; without even the implied warranty of
  13: MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  14: General Public License for more details.
  15: 
  16: You should have received a copy of the GNU General Public License
  17: along with GNU Classpath; see the file COPYING.  If not, write to the
  18: Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
  19: 02110-1301 USA.
  20: 
  21: Linking this library statically or dynamically with other modules is
  22: making a combined work based on this library.  Thus, the terms and
  23: conditions of the GNU General Public License cover the whole
  24: combination.
  25: 
  26: As a special exception, the copyright holders of this library give you
  27: permission to link this library with independent modules to produce an
  28: executable, regardless of the license terms of these independent
  29: modules, and to copy and distribute the resulting executable under
  30: terms of your choice, provided that you also meet, for each linked
  31: independent module, the terms and conditions of the license of that
  32: module.  An independent module is a module which is not derived from
  33: or based on this library.  If you modify this library, you may extend
  34: this exception to your version of the library, but you are not
  35: obligated to do so.  If you do not wish to do so, delete this
  36: exception statement from your version. */
  37: 
  38: 
  39: package java.awt;
  40: 
  41: /**
  42:  * @since 1.4
  43:  */
  44: public abstract class FocusTraversalPolicy
  45: {
  46:   /**
  47:    * Creates a <code>FocusTraversalPolicy</code> object.
  48:    */
  49:   public FocusTraversalPolicy()
  50:   {
  51:     // Do nothing in here.
  52:   }
  53: 
  54:   /**
  55:    * Returns the Component that should receive the focus after a Component.
  56:    *
  57:    * @exception IllegalArgumentException If root or current is null,
  58:    * or if root is not a focus cycle root of current.
  59:    */
  60:   public abstract Component getComponentAfter(Container root,
  61:                                               Component current);
  62: 
  63:   /**
  64:    * Returns the Component that should receive the focus before a Component.
  65:    *
  66:    * @exception IllegalArgumentException If root or current is null,
  67:    * or if root is not a focus cycle root of current.
  68:    */
  69:   public abstract Component getComponentBefore(Container root,
  70:                                                Component current);
  71: 
  72:   /**
  73:    * Returns the first Component in the traversal cycle.
  74:    *
  75:    * @exception IllegalArgumentException If root is null.
  76:    */
  77:   public abstract Component getFirstComponent(Container root);
  78: 
  79:   /**
  80:    * Returns the last Component in the traversal cycle.
  81:    *
  82:    * @exception IllegalArgumentException If root is null.
  83:    */
  84:   public abstract Component getLastComponent(Container root);
  85: 
  86:   /**
  87:    * Returns the default Component to focus.
  88:    *
  89:    * @exception IllegalArgumentException If root is null.
  90:    */
  91:   public abstract Component getDefaultComponent(Container root);
  92: 
  93:   /**
  94:    * Returns the Component that should receive the focus when a Window is made
  95:    * visible for the first time.
  96:    *
  97:    * @exception IllegalArgumentException If window is null.
  98:    */
  99:   public Component getInitialComponent(Window window)
 100:   {
 101:     return getDefaultComponent(window);
 102:   }
 103: } // class FocusTraversalPolicy