001/* PasswordCallback.java -- callback for passwords.
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 <code>PasswordCallback</code>
045 * to the <code>handle()</code> method of a {@link CallbackHandler} to retrieve
046 * password information.
047 *
048 * @see CallbackHandler,
049 */
050public class PasswordCallback implements Callback, Serializable
051{
052
053  // Constants and variables
054  // -------------------------------------------------------------------------
055
056  /**
057   * @serial
058   * @since 1.4
059   */
060  private String prompt;
061
062  /**
063   * @serial
064   * @since 1.4
065   */
066  private boolean echoOn;
067
068  /**
069   * @serial
070   * @since 1.4
071   */
072  private char[] inputPassword;
073
074  // Constructor(s)
075  // -------------------------------------------------------------------------
076
077  /**
078   * Construct a <code>PasswordCallback</code> with a prompt and a boolean
079   * specifying whether the password should be displayed as it is being typed.
080   *
081   * @param prompt the prompt used to request the password.
082   * @param echoOn <code>true</code> if the password should be displayed as it
083   * is being typed.
084   * @throws IllegalArgumentException if <code>prompt</code> is <code>null</code>
085   * or if <code>prompt</code> has a length of <code>0</code>.
086   */
087  public PasswordCallback(String prompt, boolean echoOn)
088  {
089    super();
090
091    setPrompt(prompt);
092    this.echoOn = echoOn;
093  }
094
095  // Class methods
096  // -------------------------------------------------------------------------
097
098  // Instance methods
099  // -------------------------------------------------------------------------
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}