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package com.sun.security.auth.callback;

/* JAAS imports */
import javax.security.auth.callback.Callback;
import javax.security.auth.callback.CallbackHandler;
import javax.security.auth.callback.ConfirmationCallback;
import javax.security.auth.callback.NameCallback;
import javax.security.auth.callback.PasswordCallback;
import javax.security.auth.callback.TextOutputCallback;
import javax.security.auth.callback.UnsupportedCallbackException;

/* Java imports */
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.PushbackInputStream;
import java.util.Arrays;

import sun.security.util.Password;

Prompts and reads from the command line for answers to authentication questions. This can be used by a JAAS application to instantiate a CallbackHandler

See Also:
  • callback
/** * <p> * Prompts and reads from the command line for answers to authentication * questions. * This can be used by a JAAS application to instantiate a * CallbackHandler * @see javax.security.auth.callback */
public class TextCallbackHandler implements CallbackHandler {

Creates a callback handler that prompts and reads from the command line for answers to authentication questions. This can be used by JAAS applications to instantiate a CallbackHandler.

/** * <p>Creates a callback handler that prompts and reads from the * command line for answers to authentication questions. * This can be used by JAAS applications to instantiate a * CallbackHandler. */
public TextCallbackHandler() { }
Handles the specified set of callbacks.
Params:
  • callbacks – the callbacks to handle
Throws:
/** * Handles the specified set of callbacks. * * @param callbacks the callbacks to handle * @throws IOException if an input or output error occurs. * @throws UnsupportedCallbackException if the callback is not an * instance of NameCallback or PasswordCallback */
public void handle(Callback[] callbacks) throws IOException, UnsupportedCallbackException { ConfirmationCallback confirmation = null; for (int i = 0; i < callbacks.length; i++) { if (callbacks[i] instanceof TextOutputCallback) { TextOutputCallback tc = (TextOutputCallback) callbacks[i]; String text; switch (tc.getMessageType()) { case TextOutputCallback.INFORMATION: text = ""; break; case TextOutputCallback.WARNING: text = "Warning: "; break; case TextOutputCallback.ERROR: text = "Error: "; break; default: throw new UnsupportedCallbackException( callbacks[i], "Unrecognized message type"); } String message = tc.getMessage(); if (message != null) { text += message; } if (text != null) { System.err.println(text); } } else if (callbacks[i] instanceof NameCallback) { NameCallback nc = (NameCallback) callbacks[i]; if (nc.getDefaultName() == null) { System.err.print(nc.getPrompt()); } else { System.err.print(nc.getPrompt() + " [" + nc.getDefaultName() + "] "); } System.err.flush(); String result = readLine(); if (result.equals("")) { result = nc.getDefaultName(); } nc.setName(result); } else if (callbacks[i] instanceof PasswordCallback) { PasswordCallback pc = (PasswordCallback) callbacks[i]; System.err.print(pc.getPrompt()); System.err.flush(); pc.setPassword(Password.readPassword(System.in, pc.isEchoOn())); } else if (callbacks[i] instanceof ConfirmationCallback) { confirmation = (ConfirmationCallback) callbacks[i]; } else { throw new UnsupportedCallbackException( callbacks[i], "Unrecognized Callback"); } } /* Do the confirmation callback last. */ if (confirmation != null) { doConfirmation(confirmation); } } /* Reads a line of input */ private String readLine() throws IOException { String result = new BufferedReader (new InputStreamReader(System.in)).readLine(); if (result == null) { throw new IOException("Cannot read from System.in"); } return result; } private void doConfirmation(ConfirmationCallback confirmation) throws IOException, UnsupportedCallbackException { String prefix; int messageType = confirmation.getMessageType(); switch (messageType) { case ConfirmationCallback.WARNING: prefix = "Warning: "; break; case ConfirmationCallback.ERROR: prefix = "Error: "; break; case ConfirmationCallback.INFORMATION: prefix = ""; break; default: throw new UnsupportedCallbackException( confirmation, "Unrecognized message type: " + messageType); } class OptionInfo { String name; int value; OptionInfo(String name, int value) { this.name = name; this.value = value; } } OptionInfo[] options; int optionType = confirmation.getOptionType(); switch (optionType) { case ConfirmationCallback.YES_NO_OPTION: options = new OptionInfo[] { new OptionInfo("Yes", ConfirmationCallback.YES), new OptionInfo("No", ConfirmationCallback.NO) }; break; case ConfirmationCallback.YES_NO_CANCEL_OPTION: options = new OptionInfo[] { new OptionInfo("Yes", ConfirmationCallback.YES), new OptionInfo("No", ConfirmationCallback.NO), new OptionInfo("Cancel", ConfirmationCallback.CANCEL) }; break; case ConfirmationCallback.OK_CANCEL_OPTION: options = new OptionInfo[] { new OptionInfo("OK", ConfirmationCallback.OK), new OptionInfo("Cancel", ConfirmationCallback.CANCEL) }; break; case ConfirmationCallback.UNSPECIFIED_OPTION: String[] optionStrings = confirmation.getOptions(); options = new OptionInfo[optionStrings.length]; for (int i = 0; i < options.length; i++) { options[i] = new OptionInfo(optionStrings[i], i); } break; default: throw new UnsupportedCallbackException( confirmation, "Unrecognized option type: " + optionType); } int defaultOption = confirmation.getDefaultOption(); String prompt = confirmation.getPrompt(); if (prompt == null) { prompt = ""; } prompt = prefix + prompt; if (!prompt.equals("")) { System.err.println(prompt); } for (int i = 0; i < options.length; i++) { if (optionType == ConfirmationCallback.UNSPECIFIED_OPTION) { // defaultOption is an index into the options array System.err.println( i + ". " + options[i].name + (i == defaultOption ? " [default]" : "")); } else { // defaultOption is an option value System.err.println( i + ". " + options[i].name + (options[i].value == defaultOption ? " [default]" : "")); } } System.err.print("Enter a number: "); System.err.flush(); int result; try { result = Integer.parseInt(readLine()); if (result < 0 || result > (options.length - 1)) { result = defaultOption; } result = options[result].value; } catch (NumberFormatException e) { result = defaultOption; } confirmation.setSelectedIndex(result); } }