On Tue, Dec 7, 2010 at 8:46 PM, Paul Merlin <[email protected]> wrote: > > Le 7 déc. 2010 à 13:24, Ronnie Nessa <[email protected]> a écrit : > > How can you define the order services are activated in when you call the > instantiateOnStartup method?
I can't really see the usecase where you would need an ordered startup without having the services dependent on each other, since if they have injection of the depenendency, then Qi4j will ensure that the injected service is activated before any methods are called... (Note to myself; Does this means that instantiateOnStartup should actually be called activatedOnStartup?? ) > From what I know, injection dependencies dictate the order of services > activation. Simply because a service is activated before being injected into > another. IIRC (Rickard can correct me), the ServiceReference is created at Qi4j application activation and kept in each Module. When a service is selected for injection by a direct service type reference, such as @Service MyService instance; then the Composite is created, but the activate() (if any) is not called until prior to first method invocation (unless instantiateOnStartup() has been specified). If the ServiceReference is injected; @Service ServiceReference<MyService> reference; then the service composite instance is not created until the reference.get() method is called. For @Service Iterable<MyService> instances; injection style, I am guessing that the service composite instance is not created until next() on the iterator is called and for @Service Iterable<ServiceReference<MyService>> references; I would assume that the creation is happening on the ServiceReference.get() method. Finally, for ServiceFinder lookups, I think the general idea of "as late as possible" holds true, unless the instantiateOnStartup() is specified. > But I wonder how the activation order is computed for services appart from > the dependencies point of view too. That order is "undefined" and may not remain constant over time, so even if you can figure it out, it may change without notice. I think all ServiceReferences will end up in a HashMap at some point, and then iterated through to see which ones has the instantiateOnStartup() set. Cheers -- Niclas Hedhman, Software Developer http://www.qi4j.org - New Energy for Java I live here; http://tinyurl.com/2qq9er I work here; http://tinyurl.com/2ymelc I relax here; http://tinyurl.com/2cgsug _______________________________________________ qi4j-dev mailing list [email protected] http://lists.ops4j.org/mailman/listinfo/qi4j-dev
