High-performance Concurrent MultiMap Java/Scala

java scala concurrency multimap
Viktor Klang picture Viktor Klang · Sep 3, 2010 · Viewed 17.4k times · Source

I am looking for a high-performance, concurrent, MultiMap. I have searched everywhere but I simply cannot find a solution that uses the same approach as ConcurrentHashMap (Only locking a segment of the hash array).

The multimap will be both read, added to and removed from often.

The multimap key will be a String and it's value will be arbitrary.

I need O(1) to find all values for a given key, O(N) is OK for removal, but O(logN) would be preferred.

It is crucial that removal of the last value for a given key will remove the container of values from the key, as to not leak memory.

EDIT: HERE'S THE SOLUTION I BUILT, available under ApacheV2: Index (multimap)

Answer

Rex Kerr picture Rex Kerr · Sep 3, 2010

Why not wrap ConcurrentHashMap[T,ConcurrentLinkedQueue[U]] with some nice Scala-like methods (e.g. implicit conversion to Iterable or whatever it is that you need, and an update method)?

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