public TokenValidator() {
        requiredParams.add(OAuth.OAUTH_RESPONSE_TYPE);
        requiredParams.add(OAuth.OAUTH_CLIENT_ID);
        requiredParams.add(OAuth.OAUTH_REDIRECT_URI);
    }

    @Override
    public void validateMethod(HttpServletRequest request) throws OAuthProblemException {
        String method = request.getMethod();
        if (!method.equals(OAuth.HttpMethod.GET) && !method.equals(OAuth.HttpMethod.POST)) {
            throw OAuthProblemException.error(OAuthError.CodeResponse.INVALID_REQUEST)
                .description("Method not correct.");
        }
    }

    @Override
    public void validateContentType(HttpServletRequest request) throws OAuthProblemException {
    }
}