001 // This file is part of the program FRYSK.
002 //
003 // Copyright 2005, Red Hat Inc.
004 //
005 // FRYSK is free software; you can redistribute it and/or modify it
006 // under the terms of the GNU General Public License as published by
007 // the Free Software Foundation; version 2 of the License.
008 //
009 // FRYSK is distributed in the hope that it will be useful, but
010 // WITHOUT ANY WARRANTY; without even the implied warranty of
011 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
012 // General Public License for more details.
013 //
014 // You should have received a copy of the GNU General Public License
015 // along with FRYSK; if not, write to the Free Software Foundation,
016 // Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA.
017 //
018 // In addition, as a special exception, Red Hat, Inc. gives You the
019 // additional right to link the code of FRYSK with code not covered
020 // under the GNU General Public License ("Non-GPL Code") and to
021 // distribute linked combinations including the two, subject to the
022 // limitations in this paragraph. Non-GPL Code permitted under this
023 // exception must only link to the code of FRYSK through those well
024 // defined interfaces identified in the file named EXCEPTION found in
025 // the source code files (the "Approved Interfaces"). The files of
026 // Non-GPL Code may instantiate templates or use macros or inline
027 // functions from the Approved Interfaces without causing the
028 // resulting work to be covered by the GNU General Public
029 // License. Only Red Hat, Inc. may make changes or additions to the
030 // list of Approved Interfaces. You must obey the GNU General Public
031 // License in all respects for all of the FRYSK code and other code
032 // used in conjunction with FRYSK except the Non-GPL Code covered by
033 // this exception. If you modify this file, you may extend this
034 // exception to your version of the file, but you are not obligated to
035 // do so. If you do not wish to provide this exception without
036 // modification, you must delete this exception statement from your
037 // version and license this file solely under the GPL without
038 // exception.
039
040 package frysk.gui.prefs;
041
042 import java.util.Iterator;
043 import java.util.LinkedList;
044 import java.util.prefs.Preferences;
045
046 /**
047 * BoleanPreference models a boolean-valued preference within Frysk
048 *
049 */
050 public class BooleanPreference extends FryskPreference {
051
052 public interface BooleanPreferenceListener{
053 void preferenceChanged(String prefName, boolean newValue);
054 }
055
056 protected boolean value;
057 protected boolean fallback;
058
059 protected LinkedList listeners;
060
061 /**
062 * Creates a new BooleanPreference
063 * @param name The name of the preference
064 * @param fallback The default value of the preference
065 */
066 public BooleanPreference(String name, boolean fallback) {
067 this.name = name;
068 this.fallback = fallback;
069 this.listeners = new LinkedList();
070 }
071
072 /**
073 *
074 * @return The current value of the preference
075 */
076 public boolean getCurrentValue() {
077 return this.value;
078 }
079
080 /**
081 * Sets the value of the preference. Note that this is not saved
082 * in the preferences model permanently until {@see #save(Preferences)}
083 * is called.
084 * @param val The new value
085 */
086 public void setCurrentValue(boolean val) {
087 value = val;
088 }
089
090 /**
091 * Saves the value into the model and notifies the attached
092 * listeners.
093 */
094 public void save(Preferences prefs) {
095 this.model.putBoolean(name, value);
096
097 Iterator it = this.listeners.iterator();
098 while(it.hasNext())
099 ((BooleanPreferenceListener) it.next()).preferenceChanged(this.name, this.value);
100 }
101
102 /**
103 * Sets the preference to use the provided model and loads the value from it
104 */
105 public void load(Preferences prefs) {
106 this.model = prefs;
107 this.revert();
108 }
109
110 /**
111 * Adds a listener that will be notified whenever the value
112 * of the preference is changed
113 * @param listener The object to notify
114 */
115 public void addListener(BooleanPreferenceListener listener){
116 this.listeners.add(listener);
117 listener.preferenceChanged(this.name, this.value);
118 }
119
120 /**
121 * Restores the preference from the value in the model.
122 */
123 public void revert() {
124 this.value = this.model.getBoolean(name, this.fallback);
125 }
126 }