Evaluate HazelCast instead of Ehcache

[jdubois]

Evaluate HazelCast as a replacement for Ehcache:

https://github.com/hazelcast/hazelcast/

PROs:

• Ehcache isn't actively developped anymore (as told by the Software AG sales rep)
• Looks easier to have a distributed cache
• Only way to have HTTP session clustering, without a dependancy on the app server
• Cluster affinity & distributed execution queue -> does it work well with the @scheduled annotations from Spring?

CONs:

• Last time I tried to use it, it didn't work with Hibernate 4 (not implemented yet!)
• Far less popular than Ehcache, and one of our aims is to have a project using "commonly used" technologies

Maybe this could be a new question in the Yeoman script? For instance:

• Do you want to use a cache?

1. No
2. Yes, with ehcache (simple Hibernate 2nd level cache, no clustering)
3. Yes, with HazelCast (distributed Hibernate 2nd level cache and distributed HTTP sessions)

[jmirc]

There is a beta support for Hibernate 4.0 (https://github.com/hazelcast/hazelcast-hibernate4) and the last commit was 10 months ago. Should not be used in production.

[jmirc]

This project (https://github.com/data4j/DATA4J_Spring_Hazelcast_MapLoader) uses hibernate 4 and it doesn't complain on the hibernate 4. I will try it.

[jmirc]

This example too - http://extendsobject.blogspot.ca/2013/10/hibernate-caching-with-hazelcast.html

[jdubois]

Great!

Be careful, I am refactoring the database configuration to go XML-less and change the connexion pool: I don't think there is much impact for you, and I will certainly commit this very soon.

Concerning HazelCast, we should put it as an option in the Yeoman script, because this can have a huge impact. At the moment I'm thinking of 2 questions, in fact:

• Do you want to use Hibernate 2nd level cache?

1. No
2. Yes, with ehcache (local cache, for a single node)
3. Yes, with HazelCast (distributed cache, for multiple nodes) -> default option

• Do you want to use clustered HTTP sessions?

1. No
2. Yes, with HazelCast -> default option

Are you OK with it?

[jmirc]

Yes. I will do it.

[jdubois]

Great! I'll affect you this ticket. Keep me updated :-)

[jmirc]

Actually I deactivated the GZip filter which is available with ehcache when HazelCast is selected.
I will find a workaround later. Do you have another alternative when ehcache is not used?

[jdubois]

I had forgotten about this... 1 or 2 years ago I spent a lot of time to find a good GZip filter, and it's the only one I had found.
I'll have a look again... Otherwise this could be another filter provided by JHipster, it's not a very complex piece of code.

[nikosk]

@jdubois You could take a look at this project : https://github.com/nbartels/pjl-comp-filter . I've been using this filter in production for 3-4 years now and never had a problem.

[jdubois]

Thanks! It doesn't look widely used, but it seems to do the job. And it's available on the Maven Central Repo:

http://search.maven.org/#artifactdetails%7Cnet.sourceforge.pjl-comp-filter%7Cpjl-comp-filter%7C1.7%7Cjar

[nikosk]

The github page might be misleading. It's an ancient project, originally hosted on sourceforge, so the code has seen quite a bit of use over the years.

http://sourceforge.net/projects/pjl-comp-filter/

[jdubois]

This is done and we now have two new, easier tickets to solve: #47 and #49

I will add the documentation before releasing this.