Peter,
you're right.
So if value in memcache is not of primitive type (and it can't be of
primitive type, because cache operates with objects), you can skip
cache.containsKey() call and analyze result of cache.get() with
equality to null.
In production cache.containsKey() tooks ~20 milliseconds
How I understand memcache:
cache.containsKey(some-key) tells you whether there is such key in
memcache
and cache.get(some-key) retrieves the value for key
You could skip asking for existence of the key in memcache only in
case you expect to return non-null values (and null being non-existent
