(sorry for not replying to original message, just subscribed)
This feels outright wrong:
+ static Map<String, Data> CACHE = new IdentityHashMap<>();
+
+ static Data get(String types) {
+ final String key = types.intern();
+ Data d = CACHE.get(key);
+ if (d == null) {
+ d = make(types);
+ Data e = CACHE.get(key);
+ if (e != null) {
+ d = e;
+ } else {
+ CACHE.put(key, d);
+ }
+ }
+ return d;
+ }
I couple of questions pops out in my mind:
1. Is this code supposed to be thread-safe? It is then wrong to use
unguarded IdentityHashMap without external synchronization.
2. Do we really need a second .get() check, if code is not thread-safe
anyway? This code allows two threads to call put() on the same key anyway.
3. Do the $types *need* to be interned? Or is this the premature
optimization (gone wrong, btw)?
I would rather like to see CHM.putIfAbsent()-based cache on plain
non-interned strings there. Even if interned strings are required, we
could intern them on successful map update, not every time we look up
the key.
-Aleksey.
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