Source for javax.swing.undo.StateEditable

   1: /* StateEditable.java -- Interface for collaborating with StateEdit.
   2:    Copyright (C) 2002, 2003, 2006, 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: package javax.swing.undo;
  39: 
  40: import java.util.Hashtable;
  41: 
  42: 
  43: /**
  44:  * The interface for objects whose state can be undone or redone by a
  45:  * {@link StateEdit} action.
  46:  *
  47:  * <p>The following example shows how to write a class that implements
  48:  * this interface.
  49:  *
  50:  * <pre> class Foo
  51:  *   implements StateEditable
  52:  * {
  53:  *   private String name;
  54:  *
  55:  *   public void setName(String n) { name = n; }
  56:  *
  57:  *   public void restoreState(Hashtable h)
  58:  *   {
  59:  *     if (h.containsKey("name"))
  60:  *       setName((String) h.get("name"));
  61:  *   }
  62:  *
  63:  *   public void storeState(Hashtable s)
  64:  *   {
  65:  *     s.put("name", name);
  66:  *   }
  67:  * }</pre>
  68:  *
  69:  * @see StateEdit
  70:  *
  71:  * @author Andrew Selkirk (aselkirk@sympatico.ca)
  72:  * @author Sascha Brawer (brawer@dandelis.ch)
  73:  */
  74: public interface StateEditable
  75: {
  76:   /**
  77:    * The ID of the Java source file in Sun&#x2019;s Revision Control
  78:    * System (RCS).  This certainly should not be part of the API
  79:    * specification. But in order to be API-compatible with
  80:    * Sun&#x2019;s reference implementation, GNU Classpath also has to
  81:    * provide this field and match its value. The value used here has
  82:    * been in every JDK release at least from 1.2 to 1.5.
  83:    */
  84:   String RCSID = "$" +
  85:     "Id: StateEditable.java,v 1.2 1997/09/08 19:39:08 marklin Exp $";
  86: 
  87: 
  88:   /**
  89:    * Performs an edit action, taking any editable state information
  90:    * from the specified hash table.
  91:    *
  92:    * <p><b>Note to implementors of this interface:</b> To increase
  93:    * efficiency, the <code>StateEdit</code> class {@link
  94:    * StateEdit#removeRedundantState()} removes redundant state
  95:    * information. Therefore, implementations of this interface must be
  96:    * prepared for the case where certain keys were stored into the
  97:    * table by {@link #storeState}, but are not present anymore
  98:    * when the <code>restoreState</code> method gets called.
  99:    *
 100:    * @param state a hash table containing the relevant state
 101:    * information.
 102:    */
 103:   void restoreState(Hashtable<?, ?> state);
 104: 
 105: 
 106:   /**
 107:    * Stores any editable state information into the specified hash
 108:    * table.
 109:    *
 110:    * @param state a hash table for storing relevant state
 111:    * information.
 112:    */
 113:   void storeState(Hashtable<Object, Object> state);
 114: }