private void setHeaders(String url, PostParameter[] params, HttpURLConnection connection, boolean authenticated, String httpMethod) {
        log("Request: ");
        log(httpMethod + " ", url);

        if (authenticated) {
            if ( oauth == null) {
            }
            String authorization = null;
            if (null != oauth) {
                // use OAuth
                authorization = oauth.generateAuthorizationHeader(httpMethod, url, params, oauthToken);
            } else {
                throw new IllegalStateException(
                        "Neither user ID/password combination nor OAuth consumer key/secret combination supplied");
            }
            connection.addRequestProperty("Authorization", authorization);
            log("Authorization: " + authorization);
        }
        for (String key : requestHeaders.keySet()) {
            connection.addRequestProperty(key, requestHeaders.get(key));
            log(key + ": " + requestHeaders.get(key));
        }
    }