001 /* ChoiceCallback.java -- callback for a choice of values.
002 Copyright (C) 2003, 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
039 package javax.security.auth.callback;
040
041 import java.io.Serializable;
042
043 /**
044 * Underlying security services instantiate and pass a
045 * <code>ChoiceCallback</code> to the <code>handle()</code> method of a
046 * {@link CallbackHandler} to display a list of choices and to retrieve the
047 * selected choice(s).
048 *
049 * @see CallbackHandler
050 */
051 public class ChoiceCallback implements Callback, Serializable
052 {
053
054 // Constants and variables
055 // -------------------------------------------------------------------------
056
057 /**
058 * @serial
059 * @since 1.4
060 */
061 private String prompt;
062
063 /**
064 * @serial the list of choices.
065 * @since 1.4
066 */
067 private String[] choices;
068
069 /**
070 * @serial the choice to be used as the default choice.
071 * @since 1.4
072 */
073 private int defaultChoice;
074
075 /**
076 * @serial whether multiple selections are allowed from the list of choices.
077 * @since 1.4
078 */
079 private boolean multipleSelectionsAllowed;
080
081 /**
082 * @serial the selected choices, represented as indexes into the choices list.
083 * @since 1.4
084 */
085 private int[] selections;
086
087 // Constructor(s)
088 //--------------------------------------------------------------------------
089
090 /**
091 * Construct a <code>ChoiceCallback</code> with a prompt, a list of choices,
092 * a default choice, and a boolean specifying whether or not multiple
093 * selections from the list of choices are allowed.
094 *
095 * @param prompt the prompt used to describe the list of choices.
096 * @param choices the list of choices.
097 * @param defaultChoice the choice to be used as the default choice when the
098 * list of choices are displayed. This value is represented as an index into
099 * the <code>choices</code> array.
100 * @param multipleSelectionsAllowed boolean specifying whether or not
101 * multiple selections can be made from the list of choices.
102 * @throws IllegalArgumentException if <code>prompt</code> is <code>null</code>,
103 * if <code>prompt</code> has a length of <code>0</code>, if <code>choices</code>
104 * is <code>null</code>, if <code>choices</code> has a length of <code>0</code>,
105 * if any element from <code>choices</code> is <code>null</code>, if any
106 * element from <code>choices</code> has a length of <code>0</code> or if
107 * <code>defaultChoice</code> does not fall within the array boundaries of
108 * <code>choices</code>.
109 */
110 public ChoiceCallback(String prompt, String[] choices, int defaultChoice,
111 boolean multipleSelectionsAllowed)
112 {
113 super();
114
115 setPrompt(prompt);
116 setChoices(choices);
117 if (defaultChoice < 0 || defaultChoice >= this.choices.length)
118 {
119 throw new IllegalArgumentException("default choice is out of bounds");
120 }
121 this.defaultChoice = defaultChoice;
122 this.multipleSelectionsAllowed = multipleSelectionsAllowed;
123 }
124
125 // Instance methods
126 // -------------------------------------------------------------------------
127
128 /**
129 * Get the prompt.
130 *
131 * @return the prompt.
132 */
133 public String getPrompt()
134 {
135 return prompt;
136 }
137
138 /**
139 * Get the list of choices.
140 *
141 * @return the list of choices.
142 */
143 public String[] getChoices()
144 {
145 return choices;
146 }
147
148 /**
149 * Get the defaultChoice.
150 *
151 * @return the defaultChoice, represented as an index into the choices list.
152 */
153 public int getDefaultChoice()
154 {
155 return defaultChoice;
156 }
157
158 /**
159 * Get the boolean determining whether multiple selections from the choices
160 * list are allowed.
161 *
162 * @return whether multiple selections are allowed.
163 */
164 public boolean allowMultipleSelections()
165 {
166 return multipleSelectionsAllowed;
167 }
168
169 /**
170 * Set the selected choice.
171 *
172 * @param selection the selection represented as an index into the choices
173 * list.
174 * @see #getSelectedIndexes()
175 */
176 public void setSelectedIndex(int selection)
177 {
178 this.selections = new int[1];
179 this.selections[0] = selection;
180 }
181
182 /**
183 * Set the selected choices.
184 *
185 * @param selections the selections represented as indexes into the choices
186 * list.
187 * @throws UnsupportedOperationException if multiple selections are not
188 * allowed, as determined by <code>allowMultipleSelections</code>.
189 * @see #getSelectedIndexes()
190 */
191 public void setSelectedIndexes(int[] selections)
192 {
193 if (!multipleSelectionsAllowed)
194 {
195 throw new UnsupportedOperationException("not allowed");
196 }
197
198 this.selections = selections;
199 }
200
201 /**
202 * Get the selected choices.
203 *
204 * @return the selected choices, represented as indexes into the choices list.
205 * @see #setSelectedIndexes(int[])
206 */
207 public int[] getSelectedIndexes()
208 {
209 return selections;
210 }
211
212 private void setPrompt(String prompt) throws IllegalArgumentException
213 {
214 if ((prompt == null) || (prompt.length() == 0))
215 {
216 throw new IllegalArgumentException("invalid prompt");
217 }
218 this.prompt = prompt;
219 }
220
221 private void setChoices(String[] choices) throws IllegalArgumentException
222 {
223 if (choices == null || choices.length == 0)
224 {
225 throw new IllegalArgumentException("invalid choices");
226 }
227 for (int i = 0; i < choices.length; i++)
228 {
229 if (choices[i] == null || choices[i].length() == 0)
230 {
231 throw new IllegalArgumentException("invalid choice at index #"+i);
232 }
233 }
234 this.choices = choices;
235 }
236 }