Spring Security, How do I grab the attempted username trying to log in?

Question

I have this class:

public class CustomPasswordEncoder implements PasswordEncoder {

@Autowired 
private JdbcTemplate jdbcTemplate;

@Inject
private PasswordEncoder passwordEncoder;

public String encode(CharSequence rawPassword) {

    String hashedPass;
    String userLogin;
    String encryptedPassword;

    sql = "select PasswordHash('?','?') from dual";

    hashedPass = (String)getJdbcTemplate().queryForObject(
        sql, new Object[] { userLogin,rawPassword }, String.class);

    encryptedPassword = passwordEncoder.encode(hashedPass);

    return encryptedPassword;
 }
}

What I need to do is get the USERNAME from the form and have it in the userLogin variable. I am finding it quite difficult to get the username from the form into this customized PasswordEncoder