@Override
    public boolean isAvailable(final SamlRegisteredService service) {
        if (supports(service)) {
            val locations = org.springframework.util.StringUtils.commaDelimitedListToSet(
                SpringExpressionLanguageValueResolver.getInstance().resolve(service.getMetadataLocation()));
            return locations
                .stream()
                .map(metadataLocation -> StringUtils.substringBefore(metadataLocation, "/entities/{0}"))
                .anyMatch(metadataLocation -> {
                    val status = HttpRequestUtils.pingUrl(metadataLocation);
                    return !status.isError();
                });
        }
        return false;
    }
This is {@link UrlResourceMetadataResolver}.

@author Misagh Moayyed
@since 5.2.0
support/cas-server-support-saml-idp-metadata/src/main/java/org/apereo/cas/support/saml/services/idp/metadata/cache/resolver/UrlResourceMetadataResolver.java