[hibernate-dev] Integrator locator

[Gunnar Morling]

Each provider configuration file can contain multiple implementations
of the given interface. From the JavaDoc of j.u.ServiceLoader: "The
file contains a list of fully-qualified binary names of concrete
provider classes, one per line".

>From how I understood your original requirement/implementation, I
think j.u.ServiceLoader should be exactly what you need.

2011/3/30 Steve Ebersole <steve at hibernate.org>:
> To be honest not sure what this really buys you. Basically you have to
> follow the META-INF/service/{intf-name} pattern for naming your locator file
> and that locator file, as far as I know, can only have a single entry naming
> the impl class. Which is kind of limiting. What concrete benefits do you
> actually get then? The actual resolution code is trivial.
>
> On Wednesday, March 30, 2011, at 12:21 pm, Gunnar Morling wrote:
>
>> Hi,
>
>>
>
>> since Java 1.6 this functionality is provided by
>
>> java.util.ServiceLoader [1] so when you are based on JDK 6 anyway you
>
>> could simply use that class.
>
>>
>
>> When targeting older JDKs one indeed must build it from hand (HV does
>
>> this for instance, too). Sun's JDK has contained this utility for
>
>> quite a while, but it was not part of the public API before JDK 6.
>
>>
>
>> --Gunnar
>
>>
>
>> [1]
>
>> http://download.oracle.com/javase/6/docs/api/java/util/ServiceLoader.html
>
>>
>
>> 2011/3/30 Steve Ebersole <steve at hibernate.org>:
>
>> > This is exactly what I have done.  There is no standard java mechanism
>
>> > for doing this.  Your link simply shows how one piece of java (Sound
>
>> > API) does it.
>
>> >
>
>> > On Wednesday, March 30, 2011, at 11:22 am, Adam Warski wrote:
>
>> >> Did you think about using the java services mechanism? Essentialy
>
>> >> placing a file in META-INF/services:
>
>> >>
>> >> http://download.oracle.com/javase/1.4.2/docs/guide/sound/programmer_guid
>
>> >> e/ chapter13.html ?
>
>> >>
>
>> >> I don't think it gives any functionality, but is a standard way for
>
>> >> doing such things.
>
>> >>
>
>> >> Adam
>
>> >>
>
>> >> On Mar 27, 2011, at 7:27 PM, Steve Ebersole wrote:
>
>> >> > HHH-5562 is done, which introduces a locator/discovery means for
>
>> >> > integrating with Hibernate.  Specifically it introduces the
>> >> > (alternate
>
>> >> > name suggestions welcome, i am indifferent to this one)
>
>> >> > org.hibernate.impl.Integrator interface.
>
>> >> >
>
>> >> > It does discovery based on a classpath lookup for a well-defined
>
>> >> > filename (can discover multiple) which names an implementor of this
>
>> >> > interface. The process occurs in the midst of Sessionfactory building
>
>> >> > to account for the main use cases I know of including Envers, Search,
>
>> >> > Validation and BV.  Currently I additionally define those 4 as "built
>
>> >> > in" integrators, meaning there is no need for them to define
>
>> >> > auto-discovery files unless we want them to be integrated in that
>
>> >> > manner (I know for example that Search is interested in this via
>
>> >> > HSEARCH-595).  Anyway, we should probably decide pretty early which
>
>> >> > integrations we want done which way.
>
>> >> >
>
>> >> > Actually I take one part back.  Envers is actually handed by
>> >> > discovery
>
>> >> > due to the fact that it is in a separate project (jar).  The others
>
>> >> > were done this way because they already had the reflection code in
>
>> >> > place to do this.  So for it, we need to decide if we want to go the
>
>> >> > opposite way.
>
>> >> >
>
>> >> >
>
>> >> > ---
>
>> >> > Steve Ebersole <steve at hibernate.org>
>
>> >> > http://hibernate.org
>
>> >> > _______________________________________________
>
>> >> > hibernate-dev mailing list
>
>> >> > hibernate-dev at lists.jboss.org
>
>> >> > https://lists.jboss.org/mailman/listinfo/hibernate-dev
>
>> >
>
>> > ---
>
>> > Steve Ebersole <steve at hibernate.org>
>
>> > http://hibernate.org
>
>> > _______________________________________________
>
>> > hibernate-dev mailing list
>
>> > hibernate-dev at lists.jboss.org
>
>> > https://lists.jboss.org/mailman/listinfo/hibernate-dev
>
> ---
>
> Steve Ebersole <steve at hibernate.org>
>
> http://hibernate.org