PHOENIX-5826 Remove guava from queryserver

[stoty]

No description provided.

[stoty]

The non-trivial parts are:

Copying HostAndPort with minimal changes, to ensure backward compatibility in the ZK string format

The SimpleLRUCache implementation that is used instead of Guava cache.

[joshelser]

Nice little LRU Cache implementation. I think we could've gotten away with just a ConcurrentHashMap, but your cache implementation is great.

Licensing is the biggest thing we should be aware of now. I'm assuming this is the first time you're having to deal with this. The guiding requirements from the ASF are:

1. Every artifact you distribute (src tarball, bin tarball, jars, and any/every other archive) should contain files LICENSE and NOTICE at the top-most level possible.
2. The LICENSE contains the license text of all compatibly licensed software which is included in that artifact that is not the ALv2.
3. NOTICE contains any information about included licensed code that an end user should be aware of. While this is technically "free form", it usually equates to just being copyright statements.
4. L&N files should be a "sparse" as possible. That means, we should not be including things in LICENSE or NOTICE that are unnecessary (e.g. we should not include the copyright notice from the sqlalchemy code into the Java code). This results in gymnastics around multiple copies of L&N files for each "artifact" we distribute in a release.

In a nutshell, that's how licensing works. There is documentation at the ASF on this, including https://www.apache.org/legal/resolved.html, https://www.apache.org/foundation/license-faq.html, and https://infra.apache.org/apply-license.html

As far as the code goes, this change looks good :)

[joshelser]

We should ensure that a top-level NOTICE file propagates this copyright notice, as well as the containing jar.

the ASF parent pom already has convention to append entries to the NOTICE file. One example https://github.com/apache/hbase/blob/master/hbase-thrift/src/main/appended-resources/META-INF/NOTICE. The "src/main/appended-resources" is the magic set up by asf.pom.

[stoty]

Making sure that the licensing documentation is in order seems to be a bigger task than the whole Guava removal.

I have split that out into https://issues.apache.org/jira/browse/PHOENIX-5901

[stoty]

I forgot to actually push the changes. Better late than never.

[stoty]

Thank you @joshelser .
I wasn't comfortable with the comparator returning inconsistent results when the timestamp is equal, so I've changed the implementation a bit.
Could you re-check the last commit ?

[joshelser]

Could you re-check the last commit ?

Looks fine. Thanks for double checking.