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I am currently working on an enterprise application that is deployed to GlassFish. I am attempting to figure out the right way to communicate to a cassandra backend from within an EJB that has been deployed to GlassFish 3.1. I would prefere to use Pelops to talk to Cassandra.

Disclaimer: I am new to Java EE and the concepts behind enterprise app servers and EJBs; one of the purposes of this project is to learn these topics. This is out of scope of this question as I am really just looking to be pointed in the right direction for best practices or where I should go to find best practices; so far google has not been very helpful/consistent on this topic.

More specifically, should I be thinking about writing a JCA connector for cassandra? Using a singleton EJB that talks to cassandra via Pelops? Just use pelops directly in my EJBs? (though I thought your not supposed to create socket connections in ejbs) Something else entirely?

Arjan Tijms
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Bryan
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2 Answers2

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The EJB spec prohibits EJBs from opening server sockets, but not sockets. However, it does also prohibit EJBs from creating threads. Does Pelops (or Hector) create threads to handle its pooling?

The letter of the law aside, since both those libraries do pooling, they definitely feel like something that belongs in the resource adapter layer to me. I would be nervous about EJBs, whose lifecycle is controlled by the container, and is potentially quite short, hanging on to a resource like a connection pool whose lifecycle is somewhat independent, and should be longer.

That said, most implementations of EJB are quite forgiving, so whether the use of Pelops/Hector directly from EJBs is architecturally right or not, it is very likely that it will work.

If i had all the time in the world, i would write a resource adapter wrapping one or the other of those libraries. However, that would be a considerable investment of resources in pursuit of a negligible practical return.

Tom Anderson
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we are developing a similar application where I work now, even if we do not implement EJB, we deploy a backend to Glassfish 3.1 and internally we have created a small library that talks to Cassandra.

Right now the most used library for connecting and working with Cassandra is Hector:

https://github.com/rantav/hector

It is very actively developed. I have never seen it in use inside an EJB, but I used it and it is very solid. Do not how Pelops is developed though.

What we have developed here is a very custom application tailored to our needs, that is why we didn't use Hector in the first place.

As long as you use client sockets in EJB, you should be safe, the restriction on EJB is for server socket that should be handled by the app server. But if you have other needs, you should write your JCA.

Milo Casagrande
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