libjava/javax/security/auth/callback/ChoiceCallback.java

   1 /* ChoiceCallback.java -- callback for a choice of values.
   2    Copyright (C) 2003, Free Software Foundation, Inc.
   3
   4 This file is part of GNU Classpath.
   5
   6 GNU Classpath is free software; you can redistribute it and/or modify
   7 it under the terms of the GNU General Public License as published by
   8 the Free Software Foundation; either version 2, or (at your option)
   9 any later version.
  10
  11 GNU Classpath is distributed in the hope that it will be useful, but
  12 WITHOUT ANY WARRANTY; without even the implied warranty of
  13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  14 General Public License for more details.
  15
  16 You should have received a copy of the GNU General Public License
  17 along with GNU Classpath; see the file COPYING.  If not, write to the
  18 Free Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
  19 02111-1307 USA.
  20
  21 Linking this library statically or dynamically with other modules is
  22 making a combined work based on this library.  Thus, the terms and
  23 conditions of the GNU General Public License cover the whole
  24 combination.
  25
  26 As a special exception, the copyright holders of this library give you
  27 permission to link this library with independent modules to produce an
  28 executable, regardless of the license terms of these independent
  29 modules, and to copy and distribute the resulting executable under
  30 terms of your choice, provided that you also meet, for each linked
  31 independent module, the terms and conditions of the license of that
  32 module.  An independent module is a module which is not derived from
  33 or based on this library.  If you modify this library, you may extend
  34 this exception to your version of the library, but you are not
  35 obligated to do so.  If you do not wish to do so, delete this
  36 exception statement from your version. */
  37
  38
  39 package javax.security.auth.callback;
  40
  41 import java.io.Serializable;
  42
  43 /**
  44  * Underlying security services instantiate and pass a
  45  * <code>ChoiceCallback</code> to the <code>handle()</code> method of a
  46  * {@link CallbackHandler} to display a list of choices and to retrieve the
  47  * selected choice(s).
  48  *
  49  * @see CallbackHandler
  50  */
  51 public class ChoiceCallback implements Callback, Serializable
  52 {
  53
  54   // Constants and variables
  55   // -------------------------------------------------------------------------
  56
  57   /**
  58    * @serial
  59    * @since 1.4
  60    */
  61   private String prompt;
  62
  63   /**
  64    * @serial the list of choices.
  65    * @since 1.4
  66    */
  67   private String[] choices;
  68
  69   /**
  70    * @serial the choice to be used as the default choice.
  71    * @since 1.4
  72    */
  73   private int defaultChoice;
  74
  75   /**
  76    * @serial whether multiple selections are allowed from the list of choices.
  77    * @since 1.4
  78    */
  79   private boolean multipleSelectionsAllowed;
  80
  81   /**
  82    * @serial the selected choices, represented as indexes into the choices list.
  83    * @since 1.4
  84    */
  85   private int[] selections;
  86
  87   // Constructor(s)
  88   //--------------------------------------------------------------------------
  89
  90   /**
  91    * Construct a <code>ChoiceCallback</code> with a prompt, a list of choices,
  92    * a default choice, and a boolean specifying whether or not multiple
  93    * selections from the list of choices are allowed.
  94    *
  95    * @param prompt the prompt used to describe the list of choices.
  96    * @param choices the list of choices.
  97    * @param defaultChoice the choice to be used as the default choice when the
  98    * list of choices are displayed. This value is represented as an index into
  99    * 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 }