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. 010 011 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 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 }