Hi all,

As you probably know, Will and I are working on the vert-x infinispan integration [1], where the primary goal is to make infinispan the default cluster management of vert-x. (yeah!)
Vert-x needs support for an Async Multimap. Today's implementation is a wrapper on a normal Cache where only Cache Key's are used to implement the multi map [2].
This is not very efficient, so after trying some other alternative implementations [3] that don't fully work (injection not working), Will and I have come to the conclusion that it might be a good idea to start having our own native CacheMultimap. This first multimap won't support duplicate values on key's.

As a quick start, the smallest multimap we need should implement the following interface :
public interface CacheMultimap<K, V> {
V put(K key, V value);

Collection<V> get(K key);

boolean remove(K key, V value);
}
CacheMultimapImpl will be a wrapper on a normal Cache, similar to [3].

We could add a new method in EmbeddedCacheManager.java

<K, VCacheMultimap<K, V> getCacheMultimap(String cacheName, boolean createIfAbsent);

Implementation will create a cache as always and return a new CacheMultimapImpl(cache). 

What do you think ? Please fell free to suggest any other alternative or idea.

Cheers

Katia

[1] https://github.com/vert-x3/vertx-infinispan

[2] https://github.com/vert-x3/vertx-infinispan/blob/master/src/main/java/io/vertx/ext/cluster/infinispan/impl/InfinispanAsyncMultiMap.java

[3] https://gist.github.com/karesti/194bb998856d4a2828d83754130ed79c