private Set<TKey<?, ?>> setupPortalKeys() {
        Set<TKey<?, ?>> portalKeys = new LinkedHashSet<>();

        portalKeys.add(ProviderKeys.PORTAL_STATUS);
        portalKeys.add(ProviderKeys.COORDINATE);
        portalKeys.add(ProviderKeys.LINK);

        validQualifiers.put(ProviderKeys.LINK, new LinkedHashSet<Class<? extends Enum<?>>>() {
            {
                add(ProviderQualifiers.LINK_TYPE);
            }
        });

        qualifiers.add(ProviderQualifiers.LINK_TYPE);

        uniqueKeys.add(ProviderKeys.PORTAL_STATUS);
        uniqueKeys.add(ProviderKeys.COORDINATE);

        return portalKeys;
    }