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

   1 /* PasswordCallback.java -- callback for passwords.
   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 <code>PasswordCallback</code>
  45  * to the <code>handle()</code> method of a {@link CallbackHandler} to retrieve
  46  * password information.
  47  *
  48  * @see CallbackHandler,
  49  */
  50 public class PasswordCallback implements Callback, Serializable
  51 {
  52
  53   // Constants and variables
  54   // -------------------------------------------------------------------------
  55
  56   /**
  57    * @serial
  58    * @since 1.4
  59    */
  60   private String prompt;
  61
  62   /**
  63    * @serial
  64    * @since 1.4
  65    */
  66   private boolean echoOn;
  67
  68   /**
  69    * @serial
  70    * @since 1.4
  71    */
  72   private char[] inputPassword;
  73
  74   // Constructor(s)
  75   // -------------------------------------------------------------------------
  76
  77   /**
  78    * Construct a <code>PasswordCallback</code> with a prompt and a boolean
  79    * specifying whether the password should be displayed as it is being typed.
  80    *
  81    * @param prompt the prompt used to request the password.
  82    * @param echoOn <code>true</code> if the password should be displayed as it
  83    * is being typed.
  84    * @throws IllegalArgumentException if <code>prompt</code> is <code>null</code>
  85    * or if <code>prompt</code> has a length of <code>0</code>.
  86    */
  87   public PasswordCallback(String prompt, boolean echoOn)
  88   {
  89     super();
  90
  91     setPrompt(prompt);
  92     this.echoOn = echoOn;
  93   }
  94
  95   // Class methods
  96   // -------------------------------------------------------------------------
  97
  98   // Instance methods
  99   // -------------------------------------------------------------------------
 100
 101   /**
 102    * Get the prompt.
 103    *
 104    * @return the prompt.
 105    */
 106   public String getPrompt()
 107   {
 108     return prompt;
 109   }
 110
 111   /**
 112    * Return whether the password should be displayed as it is being typed.
 113    *
 114    * @return the whether the password should be displayed as it is being typed.
 115    */
 116   public boolean isEchoOn()
 117   {
 118     return echoOn;
 119   }
 120
 121   /**
 122    * <p>Set the retrieved password.</p>
 123    *
 124    * <p>This method makes a copy of the input password before storing it.</p>
 125    *
 126    * @param password the retrieved password, which may be <code>null</code>.
 127    * @see #getPassword()
 128    */
 129   public void setPassword(char[] password)
 130   {
 131     inputPassword = (password == null ? null : (char[]) password.clone());
 132   }
 133
 134   /**
 135    * <p>Get the retrieved password.</p>
 136    *
 137    * <p>This method returns a copy of the retrieved password.</p>
 138    *
 139    * @return the retrieved password, which may be <code>null</code>.
 140    * @see #setPassword(char[])
 141    */
 142   public char[] getPassword()
 143   {
 144     return (inputPassword == null ? null : (char[]) inputPassword.clone());
 145   }
 146
 147   /** Clear the retrieved password. */
 148   public void clearPassword()
 149   {
 150     if (inputPassword != null)
 151       {
 152         for (int i = 0; i < inputPassword.length; i++)
 153           {
 154             inputPassword[i] = '\0';
 155           }
 156         inputPassword = null;
 157       }
 158   }
 159
 160   private void setPrompt(String prompt) throws IllegalArgumentException
 161   {
 162     if ((prompt == null) || (prompt.length() == 0))
 163       {
 164         throw new IllegalArgumentException("invalid prompt");
 165       }
 166     this.prompt = prompt;
 167   }
 168 }