toolchain/gcc/libjava/javax/swing/undo/StateEditable.java

   1 /* StateEditable.java -- Interface for collaborating with StateEdit.
   2    Copyright (C) 2002, 2003 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., 59 Temple Place, Suite 330, Boston, MA
  19 02111-1307 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. However, we do not try to match its value.
  82    */
  83   String RCSID = "";
  84
  85
  86   /**
  87    * Performs an edit action, taking any editable state information
  88    * from the specified hash table.
  89    *
  90    * <p><b>Note to implementors of this interface:</b> To increase
  91    * efficiency, the <code>StateEdit</code> class {@linkplan
  92    * StateEdit#removeRedundantState() removes redundant state
  93    * information}. Therefore, implementations of this interface must be
  94    * prepared for the case where certain keys were stored into the
  95    * table by {@link #storeState}, but are not present anymore
  96    * when the <code>restoreState</code> method gets called.
  97    *
  98    * @param state a hash table containing the relevant state
  99    * information.
 100    */
 101   void restoreState(Hashtable state);
 102
 103
 104   /**
 105    * Stores any editable state information into the specified hash
 106    * table.
 107    *
 108    * @param state a hash table for storing relevant state
 109    * information.
 110    */
 111   void storeState(Hashtable state);
 112 }