@SuppressWarnings("JdkObsolete")
    protected List<String> resolveEventFromHttpRequest(final HttpServletRequest request) {
        val mfaRequestHeader = casProperties.getAuthn().getMfa().getTriggers().getHttp().getRequestHeader();
        val headers = request.getHeaders(mfaRequestHeader);
        if (headers != null && headers.hasMoreElements()) {
            LOGGER.debug("Received request header [{}] as [{}]", mfaRequestHeader, headers);
            return Collections.list(headers);
        }

        val mfaRequestParameter = casProperties.getAuthn().getMfa().getTriggers().getHttp().getRequestParameter();
        val params = request.getParameterValues(mfaRequestParameter);
        if (params != null && params.length > 0) {
            LOGGER.debug("Received request parameter [{}] as [{}]", mfaRequestParameter, params);
            return Arrays.stream(params).collect(Collectors.toList());
        }

        val attributeName = casProperties.getAuthn().getMfa().getTriggers().getHttp().getSessionAttribute();
        val session = request.getSession(false);
        var attributeValue = Optional.ofNullable(session).map(httpSession -> httpSession.getAttribute(attributeName)).orElse(null);
        if (attributeValue == null) {
            LOGGER.trace("No value could be found for session attribute [{}]. Checking request attributes...", attributeName);
            attributeValue = request.getAttribute(attributeName);
        }

        if (attributeValue == null) {
            LOGGER.trace("No value could be found for [{}]", attributeName);
            return null;
        }

        val values = CollectionUtils.toCollection(attributeValue);
        LOGGER.debug("Found values [{}] mapped to attribute name [{}]", values, attributeName);
        return values.stream().map(Object::toString).collect(Collectors.toList());
    }
Resolve event from http request.

@param request the request
@return the list
core/cas-server-core-authentication-mfa-api/src/main/java/org/apereo/cas/authentication/mfa/trigger/HttpRequestMultifactorAuthenticationTrigger.java