* It's suggested by http://redis.io/topics/cluster-spec
** antirez/redis-rb-cluster implementation does it, too
* Since Redis 3.0-beta 7 introduces CLUSTER SLOTS, it becomes easier
* FIXME: It's fully synchronized, so it hurts performance (somewhat poor implementation)
** We can try Reader / Writer strategy to make lock waiting make shorter
JedisClusterCommand
* improvements on connection error handling
** if based on slot connection throws connection related exception, retry to random node
** if we retry with random node, but all nodes are unreachable, throw JedisConnectionException without retry
** try to release connection whether connection is broken or not
* bug fix : if asking flag is on, and success this time, set asking flag to off
JedisClusterConnectionHandler
* have flexibility on initializing slots cache
** allow some nodes connection failure - skip
** if current node is success initializing slots cache, skip other nodes
** if current node failed to initialize slots cache, discard all discovered nodes and slots
* set nodes if node does not exist in nodes
** it restricts JedisPool to replace - prevent IllegalStateException : Returned object not currently part of this pool
JedisSlotBasedConnectionGuaranteedConnectionHandler
* getConnection (random connection)
** check all connections by random sequence
** always return valid connection (able to ping-pong)
** throw exception if all connections are invalid
* some refactoring
- Add asking to cluster commands
- Make jedis cluster return connection to original pool
- Add tests for MOVED and ASK cluster responses
- Refactor connection handler to recalculate connections based on slots
This commit makes the first usable version of Jedis along with Redis Cluster
