/* Interacts with the user to get a name and password. 
 */

import javax.security.auth.callback.Callback;
import javax.security.auth.callback.NameCallback;
import javax.security.auth.callback.PasswordCallback;
import javax.security.auth.callback.CallbackHandler;
import javax.security.auth.callback.UnsupportedCallbackException;
import java.io.*;

public class NPCallbackHandler implements CallbackHandler {
  public void handle(Callback callbacks[]) throws
              IOException, UnsupportedCallbackException {
    for(int i=0; i<callbacks.length; i++)
      if (callbacks[i] instanceof NameCallback) {
        NameCallback n = (NameCallback)callbacks[i];
        System.out.println(n.getPrompt());
        BufferedReader reader = new BufferedReader(
            new InputStreamReader(System.in));
        String name = reader.readLine();
        n.setName(name);
      }else if (callbacks[i] instanceof PasswordCallback) {
        PasswordCallback p = (PasswordCallback)callbacks[i];
        System.out.println(p.getPrompt());
        BufferedReader reader = new BufferedReader(
            new InputStreamReader(System.in));
        String password = reader.readLine();
        p.setPassword(password.toCharArray());
      }else
        throw (new UnsupportedCallbackException
            (callbacks[i], "Not supported"));
  }
}