public class CustomAuthenticationProvider implements AuthenticationProvider {

@Autowired
AccountService accountService;

@Override
public Authentication authenticate(Authentication authentication) throws AuthenticationException {

    String name = authentication.getName();
    String password = authentication.getCredentials().toString();

    Account user;

    try {
        if (name.contains("@")) {
            user = accountService.findAccount(new AccountSpecificationByEmail(name));
        } else {
            user = accountService.findAccount(new AccountSpecificationByUserName(name));
        }
    } catch (AccountNotFoundException e) {
        throw new RuntimeException("Wrong login or password");
    }

    if (user.getPassword().equals(password)){
        if (user.getRoles().contains(`***chosenRole***`)){
            List<GrantedAuthority> grantedAuths = new ArrayList<>();
            grantedAuths.add(new SimpleGrantedAuthority(`***chosenRole***`));
            Authentication auth = new UsernamePasswordAuthenticationToken(name, password, grantedAuths);
            return auth;
        }
        else{
            throw new RuntimeException("Role not supported");
        }
    }
    else {
        throw new RuntimeException("Wrong login or password");
    }


}

@Override
public boolean supports(Class<?> authentication) {
    return authentication.equals(UsernamePasswordAuthenticationToken.class);
}