001/* ChoiceCallback.java -- callback for a choice of values.
002   Copyright (C) 2003, 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
038
039package javax.security.auth.callback;
040
041import 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 */
051public 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}