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}