public void handle(Callback[] callbacks)
    throws IOException, UnsupportedCallbackException {
      
	for (int i = 0; i < callbacks.length; i++) {
	    if (callbacks[i] instanceof TextOutputCallback) {
      
		// display the message according to the specified type
		TextOutputCallback toc = (TextOutputCallback)callbacks[i];
		switch (toc.getMessageType()) {
		case TextOutputCallback.INFORMATION:
 		    System.out.println(toc.getMessage());
 		    break;
 		case TextOutputCallback.ERROR:
 		    System.out.println("ERROR: " + toc.getMessage());
 		    break;
 		case TextOutputCallback.WARNING:
 		    System.out.println("WARNING: " + toc.getMessage());
 		    break;
 		default:
 		    throw new IOException("Unsupported message type: " +
 					toc.getMessageType());
 		}
 
 	    } else if (callbacks[i] instanceof NameCallback) {
  
 		// prompt the user for a username
 		NameCallback nc = (NameCallback)callbacks[i];
  
 		System.err.print(nc.getPrompt());
 		System.err.flush();
 		nc.setName((new BufferedReader
			(new InputStreamReader(System.in))).readLine());
 
 	    } else if (callbacks[i] instanceof PasswordCallback) {
  
 		// prompt the user for sensitive information
 		PasswordCallback pc = (PasswordCallback)callbacks[i];
 		System.err.print(pc.getPrompt());
 		System.err.flush();
 		pc.setPassword(readPassword(System.in));
  
 	    } else {
 		throw new UnsupportedCallbackException
 			(callbacks[i], "Unrecognized Callback");
 	    }
	}
    }