HonestyWorks TechNote

これでいいのかしら。。

    public static Key allocateId(AsyncDatastoreService ds, String kind)
            throws NullPointerException {
        if (ds == null) {
            throw new NullPointerException("The ds parameter must not be null.");
        }
        if (kind == null) {
            throw new NullPointerException(
                "The kind parameter must not be null.");
        }
        String ns = NamespaceManager.get();
        if (ns == null) {
        	ns = "";
        }
        String cacheKey = "!"+ns+":"+kind;
        Iterator<Key> keys = keysCache.get(cacheKey);
        if (keys != null && keys.hasNext()) {
            return keys.next();
        }
        keys =
            FutureUtil
                .getQuietly(allocateIdsAsync(ds, kind, KEY_CACHE_SIZE))
                .iterator();
        keysCache.put(cacheKey, keys);
        return keys.next();
    }