001/* StateEditable.java -- Interface for collaborating with StateEdit. 002 Copyright (C) 2002, 2003, 2006, Free Software Foundation, Inc. 003 004This file is part of GNU Classpath. 005 006GNU Classpath is free software; you can redistribute it and/or modify 007it under the terms of the GNU General Public License as published by 008the Free Software Foundation; either version 2, or (at your option) 009any later version. 010 011GNU Classpath is distributed in the hope that it will be useful, but 012WITHOUT ANY WARRANTY; without even the implied warranty of 013MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 014General Public License for more details. 015 016You should have received a copy of the GNU General Public License 017along with GNU Classpath; see the file COPYING. If not, write to the 018Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 01902110-1301 USA. 020 021Linking this library statically or dynamically with other modules is 022making a combined work based on this library. Thus, the terms and 023conditions of the GNU General Public License cover the whole 024combination. 025 026As a special exception, the copyright holders of this library give you 027permission to link this library with independent modules to produce an 028executable, regardless of the license terms of these independent 029modules, and to copy and distribute the resulting executable under 030terms of your choice, provided that you also meet, for each linked 031independent module, the terms and conditions of the license of that 032module. An independent module is a module which is not derived from 033or based on this library. If you modify this library, you may extend 034this exception to your version of the library, but you are not 035obligated to do so. If you do not wish to do so, delete this 036exception statement from your version. */ 037 038package javax.swing.undo; 039 040import 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 */ 074public 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}