IMap partition-key strategy

[pveentjer]

There is some control to determine the correct partition of a IMap key:

1. if it implement PartitionAware the binary format of the getPartitionKey will be used to determine the partition
2. if it doesn't, the binary format of the key is used.

It would be nice if there would be a PartitionStrategy that can be inserted in the map:

interface PartitionStrategy<K>{
    Object getPartitionKey(K k);
}

The default implementation can behave like what we have now; if the key implement partition aware then use that otherwise use key itself.

But a user can also provide his own partitionstrategy; he could for example have a partitionstrategy that relies on e.g. foo@hazelcast

So with this PartitionStrategy we can easily provide the functionality which is there and if nothing configured explicitly by the user than the system will behave like it always has. But the user can also inject his own partition strategy.

[mdogan]

Fixed by commit; 1ec1558