package com.smaple.login;

import java.io.IOException;
import java.util.Map;

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.callback.UnsupportedCallbackException;
import javax.security.auth.login.LoginException;
import javax.security.auth.spi.LoginModule;

public class BasicLoginModule implements LoginModule {

private String username = "krishna";
private String password = "krishna";
 CallbackHandler callbackHandler;

@Override
public void initialize(Subject subject, CallbackHandler callbackHandler, MapString, ?> sharedState,
   MapString, ?> options) {
this.callbackHandler = callbackHandler;
}

@Override
public boolean login() throws LoginException {
  Callback[] callbackArray = new Callback[2];

  callbackArray[0] = new NameCallback("Enter logon id:");
  callbackArray[1] = new PasswordCallback("Enter password:", false);

try {
   callbackHandler.handle(callbackArray);
} catch (IOException | UnsupportedCallbackException e) {
   e.printStackTrace();
throw new LoginException(e.getMessage());
}

  String logonId = ((NameCallback) callbackArray[0]).getName();
char[] passwordArr = ((PasswordCallback) callbackArray[1]).getPassword();
  String password = new String(passwordArr);

if (username.equals(logonId) && this.password.equals(password)) {
   System.out.println("Login successful");
return true;
}

throw new LoginException("Logon failed");
}

@Override
public boolean commit() throws LoginException {
return true;
}

@Override
public boolean abort() throws LoginException {
return false;
}

@Override
public boolean logout() throws LoginException {
return true;
}

}