001 /* StateEditable.java -- Interface for collaborating with StateEdit.
002 Copyright (C) 2002, 2003, 2006, 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
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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
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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 package javax.swing.undo;
039
040 import java.util.Hashtable;
041
042
043 /**
044 * The interface for objects whose state can be undone or redone by a
045 * {@link StateEdit} action.
046 *
047 * <p>The following example shows how to write a class that implements
048 * this interface.
049 *
050 * <pre> class Foo
051 * implements StateEditable
052 * {
053 * private String name;
054 *
055 * public void setName(String n) { name = n; }
056 *
057 * public void restoreState(Hashtable h)
058 * {
059 * if (h.containsKey("name"))
060 * setName((String) h.get("name"));
061 * }
062 *
063 * public void storeState(Hashtable s)
064 * {
065 * s.put("name", name);
066 * }
067 * }</pre>
068 *
069 * @see StateEdit
070 *
071 * @author Andrew Selkirk (aselkirk@sympatico.ca)
072 * @author Sascha Brawer (brawer@dandelis.ch)
073 */
074 public interface StateEditable
075 {
076 /**
077 * The ID of the Java source file in Sun’s Revision Control
078 * System (RCS). This certainly should not be part of the API
079 * specification. But in order to be API-compatible with
080 * Sun’s reference implementation, GNU Classpath also has to
081 * provide this field and match its value. The value used here has
082 * been in every JDK release at least from 1.2 to 1.5.
083 */
084 String RCSID = "$" +
085 "Id: StateEditable.java,v 1.2 1997/09/08 19:39:08 marklin Exp $";
086
087
088 /**
089 * Performs an edit action, taking any editable state information
090 * from the specified hash table.
091 *
092 * <p><b>Note to implementors of this interface:</b> To increase
093 * efficiency, the <code>StateEdit</code> class {@link
094 * StateEdit#removeRedundantState()} removes redundant state
095 * information. Therefore, implementations of this interface must be
096 * prepared for the case where certain keys were stored into the
097 * table by {@link #storeState}, but are not present anymore
098 * when the <code>restoreState</code> method gets called.
099 *
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 }