Re: [infinispan-dev] Infinispan's dependency injection fwk

They can't be final. The whole point of injecting stuff is that components go through a lifecycle: 1) Configure. This is where components are created and wired together. 2) Start. Now in between 1 and 2, if someone still has a reference to the Configuration instance and changes some stuff, these changes would need to be reflected in the runtime.

Which means some components may need to be re-injected with different implementations. In terms of safe publishing, you can consider this safe since in the start method of the ComponentRegistry, internal volatile fields (including some locks) are touched, which means a JMM fence [1] is crossed.

So even non-volatile variables would be properly published by this time since all out-of-order operations need to complete for the fence. Now normally this would be considered hackish since subsequent writes to the variables in question may not be published properly, however we ensure that the ComponentRegistry is the only component capable of injecting stuff, and the CR will make sure there is a fence every time. HTH Manik [1] http://en.wikipedia.org/wiki/Memory_barrier On 22 Jul 2010, at 17:22, Mircea Markus wrote: > Hi, > > I have this problem with the the dependency injection fwk in infinispan: many times I'd like to declare the injected dependencies as final fields in order to take advantage[1] of "final" semantics in Java's memory model. I cannot/don't know how to do that, can I annotate an constructor with @Inject? If not I think that would be useful. > > [1] @Inject methods are called by the thread that starts the CM. The injected dependencies are cached as local fields and will be accessed by a different application thread. So they'd need volatile/synchronise for proper publishing: afaik volatile is less performant that publishing with final. > > wdyt? > > Cheers, > Mircea > _______________________________________________ > infinispan-dev mailing list > infinispan-dev(a)lists.jboss.org > https://lists.jboss.org/mailman/listinfo/infinispan-dev -- Manik Surtani manik(a)jboss.org Lead, Infinispan Lead, JBoss Cache http://www.infinispan.org http://www.jbosscache.org _______________________________________________ infinispan-dev mailing list infinispan-dev(a)lists.jboss.org https://lists.jboss.org/mailman/listinfo/infinispan-dev