class ExpiringCacheMap {

    public synchronized Collection<@Nullable V> values() {
        final Collection<@Nullable V> values = new LinkedList<>();
        for (final ExpiringCache<@Nullable V> item : items.values()) {
            values.add(item.getValue());
        }
        return values;
    }

    public  ExpiringCacheMap(Duration expiry);
    public  ExpiringCacheMap(long expiry);

}