Concurrent Access to Seam Component

[freakwave10]

Hi all,

sorry for my lack of the technical details here, but still trying to learn.
To simplify lets assume I have the following POJO components:

- gateway (EventScope)
- commandScheduler (ApplicationScope)
- job (EventScope)

now the job is executed by quartz. I am setting up everything in the commandScheduler and creating a job with a reference to the gateway.
Since I am storing the gateway in a class variable in the commandScheduler, this eventscope has basically the same lifecycle as the whole application scope.

Now my questions:
Since all jobs basically share the same gateway instance, how does this affect my performance? Could I run into concurrency problems? This is almost like a pojo singleton.
On the other hand I could always create a new gateway instance for every job and pass it to the new job, but this is also kind of expensive.
Finally this could be a good use case for a stateless session bean.

Thanks a lot for some theoretical insight.

Wolfgang

[freakwave10]

Perhaps I should add that my gateway does not have any shared instance variables, only local variables in the methods.

[lvdberg]

Hi,

I know that Seam synchronizes access to beans and besides that the Seam framework provides for a Synchronizer (annotation) which takes care of async access.

I prefer NOT to depend on the framework for this specific area, but to build a simple synchronized Queue myself, since Java 5 there is a concurrency package which simplifies the task substantially (basically a few lines). This allows you to add things like priorities also, something which Seam doesn' have at the moment.

Leo