Generic InternPool in Java?

Question

How would I write a generic InternPool in Java? Does it need a Internable interface?

String in Java has interning cap

Answer 1

Just a quick caveat:

It has not been explicitly mentioned above, but it should be obvious that the objects being interned must be of an immutable type.

On a second note: You don't need to use another weak reference to the object as the value in the map, a reference to a static would suffice if you just rely on the map's keyset for the data. For example, declare:

WeakHashMap

And insert pairs as:

pool.put (object, Boolean.TRUE);

Which is a minor saving of a WeakReference instance (if you can't reuse the one used for the key).

...or create a WeakSet class, as @PeterVerhas has done with his WeakPool.