change exists command to variodic

[charsyam]

today, redis exists command is changed to variodic.

[HeartSaVioR]

@charsyam
Mixed define of * and specific cases in import static Command, which would be better to fix it.
Using one way would be fine, so you can just remove specific cases import statements.

[HeartSaVioR]

@charsyam
Looks fine to me, I left some comments which guides you to respect semver, and some other things.

Btw, your changeset breaks indentation, which can be fixed by running make format.
Please refer https://github.com/xetorthio/jedis/blob/master/CONTRIBUTING.md#code-convention for more details.

Thanks for the great work!

[HeartSaVioR]

@charsyam
I've found some more things to do.
Please make some effort to

1. BinaryJedisCommands
   a. add Long exists(byte[][] key);
   b. mark @deprecated to Boolean exists(byte[] key);
2. BinaryClient
   a. apply my comment (maybe missing)

Other things are fine. Whenever you're completing your work, I'll label as WAIT FOR MORE REVIEWS.
Thanks!

[HeartSaVioR]

Talking with @charsyam , I completely forgot to tell while adding new commands to Jedis.
Since operation we'd like to add it multi keys operation, we should start adding method signature to interfaces below,

• multi key, binary: MultiKeyBinaryCommands
• multi key, binary, cluster: MultiKeyBinaryJedisClusterCommands
• multi key, binary, pipeline: MultiKeyBinaryRedisPipeline
• multi key, normal: MultiKeyCommands
• multi key, normal, cluster: MultiKeyJedisClusterCommands
• multi key, normal, pipeline: MultiKeyCommandsPipeline

It should be safe with ShardedJedis* cause ShardedJedis only treats singular key operations.

@charsyam Sorry about the confusing. It must be documented to CONTRIBUTING.md soon.

[HeartSaVioR]

@charsyam
Looks great to me.
Last one thing I'd like to ask a favor is adding @deprecated annotation to JedisCluster.exists(final String key).

@xetorthio @marcosnils
As you know, there should be two different PRs which one deprecates methods at 2.7 / 2.8 version lines, and next one removes method at 3.0.0.
This PR doesn't respect it, but I think I can manage it. I'd like to adding some modifications during merging step.

[HeartSaVioR]

@xetorthio @marcosnils
We decided to remove ShardedJedis at 3.0.0, right?
Deprecating exist() with singular key is based on decision. (If we don't remove ShardedJedis, we should maintain two version of methods, singular key and multiple key.)

Please review and comment. Thanks!

[HeartSaVioR]

FYI: exists with vargs is included to Redis 3.0.3.

[marcosnils]

@HeartSaVioR haven't had time to review, sorry. I'll take a look tomorrow.

[charsyam]

Redis 3.0.3 is out. and It contains Variadic Exists.

[HeartSaVioR]

Since it didn't reviewed for long time, I think it's better to merge than waiting more.

[HeartSaVioR]

@charsyam Thanks for amazing work! I merged into master and 2.8 respectively.

[charsyam]

@HeartSaVioR Thanks. :)