/* A custom login module
 */

import java.util.*;
import javax.security.auth.Subject;
import javax.security.auth.callback.Callback;
import javax.security.auth.callback.CallbackHandler;
import javax.security.auth.callback.NameCallback;
import javax.security.auth.callback.PasswordCallback;
import javax.security.auth.spi.LoginModule;
import javax.security.auth.login.LoginException;

public class NPLoginModule implements LoginModule {
  private Subject subject;
  private CallbackHandler handler;
  private boolean success;
  private String name;
  private String password;
  private NamePrincipal np;

  public void initialize(Subject s, CallbackHandler c,
             Map<String, ?> state, Map<String, ?> options) {
    subject = s;
    handler = c;
  }
  public boolean login() throws LoginException {
    success = false;
    Callback[] callback = new Callback[2];
    callback[0] = new NameCallback("Enter your user name");
    callback[1] = 
         new PasswordCallback("Enter your password", false);
    try {
      handler.handle(callback);
      name = ((NameCallback)callback[0]).getName();
      password = new String(((PasswordCallback)callback[1]).getPassword());
      if (name.equals("art")
          && password.equals("1234")) {
         success = true;
      }
    }catch(Exception e) {
      e.printStackTrace();
    } 
    return success;
  }
  public boolean commit() throws LoginException {
    if (success) {
       np = new NamePrincipal("np");
       subject.getPrincipals().add(np);
    }
    return success;
  }
  public boolean abort() throws LoginException {
    boolean ret = false;
    name = null;
    if (success) {
      ret = true;
      subject.getPrincipals().remove(np);
    }
    return ret;      
  }
  public boolean logout() throws LoginException {
    name = null;
    if (success) 
      subject.getPrincipals().remove(np);
    return true;
  }
}