On 12 Jan 2012, at 3:00 PM, Steve Ebersole wrote: > "Java services api" == ServiceLoader I assume? correct > Going on that assumption: > > No. ServiceLoader is just a discovery mechanism. There still needs to be something that, as you say, negotiates amongst the various discovered implementations of a particular service. 2 well known ServiceLoader uses are JDBC drivers and image processors, each illustrating a different approach that are really inherent to their respective problem domains. In the case of JDBC drivers, the discovery is just used to register all the available drivers; users must still specify which driver they want via JDBC url protocol. In the case of image processing (as I understand it anyway, not really my forte) the choice of processor is more intrinsic to the image you ask to have processed based on MIME type. > > Here is sound like you more have the JDBC style, where discovery is just making the complete set of possibilities known. The user would still need to make a distinction. Or maybe you have some special rules like (a) using the standard service if it is the only one discovered; (b) using the "other" service if 2 are discovered; (c) requiring the user tell you if 3 or more are found. Many ways to skin that cat. Right. I would expect the user to make this distinction via the configuration.

I think really the problem is that what we have is actually not a ServiceManager (at least not what I understand under this term). It is a fancy way to instantiating a class and giving it a life cycle (aka #start(), #stop()). We really have more of a BeanLifeCycleManager.

--Hardy _______________________________________________ hibernate-dev mailing list hibernate-dev(a)lists.jboss.org https://lists.jboss.org/mailman/listinfo/hibernate-dev

On Fri 2012-10-12 15:13, Hardy Ferentschik wrote: > > On 12 Jan 2012, at 3:00 PM, Steve Ebersole wrote: > >> "Java services api" == ServiceLoader I assume? > > correct > >> Going on that assumption: >> >> No. ServiceLoader is just a discovery mechanism. There still needs to be something that, as you say, negotiates amongst the various discovered implementations of a particular service. 2 well known ServiceLoader uses are JDBC drivers and image processors, each illustrating a different approach that are really inherent to their respective problem domains. In the case of JDBC drivers, the discovery is just used to register all the available drivers; users must still specify which driver they want via JDBC url protocol. In the case of image processing (as I understand it anyway, not really my forte) the choice of processor is more intrinsic to the image you ask to have processed based on MIME type. >> >> Here is sound like you more have the JDBC style, where discovery is just making the complete set of possibilities known. The user would still need to make a distinction. Or maybe you have some special rules like (a) using the standard service if it is the only one discovered; (b) using the "other" service if 2 are discovered; (c) requiring the user tell you if 3 or more are found. Many ways to skin that cat. > > Right. I would expect the user to make this distinction via the configuration. > > I think really the problem is that what we have is actually not a ServiceManager (at least not what I understand under this term). It is a fancy way to instantiating a class and giving it a life cycle (aka #start(), #stop()). > We really have more of a BeanLifeCycleManager. Basically for you a Service must allow for multiple implementations and a ServiceManager must offer a way to switch between various implementations.

I don't see how renaming this class a BeanLifeCycleManager makes any of this better.