Werner
Hi,
Since the release of JDK 9 is behind the corner, it would be good to update the spec to be ready for it.
I can see 2 things which can be done:1) JPA_SPEC-145: define module name
I'm not 100% sure this needs to be done but for the sake of completeness - it is clear that the module name should be 'java.persistence'. While it would be nice to have the name defined and available, do we really need this or should we stick with API being resolved on JDK9 as an automatic module?
I'm proposing to NOT touch this area in the spec now and keep this up to the provider. Any opinions?
2) JPA_SPEC-146: Use ServiceLoader facility
with the introduction of the module system there are currently 2 ways, how persistence provider implementation can be defined - META-INF/services and module-info with 'provides ... with...'. Former way is already covered but the latter is not, so I'd like to propose following change to Section 9.2 of the spec (additions are in italics, removals are striked-through italics)
Section 9.2 Bootstrapping in Java SE Environments
In Java SE environments, the Persistence.createEntityManagerFactory method is used
by the application to create an entity manager factory.
A persistence provider implementation running in a Java SE environment should also act as a service
provider by supplying a service provider configurationfile as described in the JAR File Specification. The Persistence
bootstrap class should use ServiceLoader facility to locate all available provider implementations.
The provider configurationfileserves to export the provider implementation class to the Persistence
bootstrap class, positioning the provider as a candidate for backing named persistence units.
The provider may supply the provider configuration file by creating a text file named javax.persistence.spi.PersistenceProvider
and placing it in the META-INF/services directory of
one of its JAR files. The contents of the file should be the name of the provider implementation class of
the javax.persistence.spi.PersistenceProvider interface.
Example 1:
A persistence vendor called ACME persistence products ships a JAR called acme.jar that contains
its persistence provider implementation. The JAR includes the provider configuration file.
acme.jar
META-INF/services/javax.persistence.spi.PersistenceProvider
com.acme.PersistenceProvider
…
The contents of the META-INF/services/javax.persistence.spi.PersistenceProvider
file is nothing more than the name of the implementation class: com.acme.PersistenceProvider.
Example 2:
A persistence vendor called ACME persistence products ships a module called acme.jar that provides persistence provider implementation. The JAR contains module definition which contains the name of the implementation class.
acme.jar
module-info.class
…
module acme {
provides javax.persistence.spi.PersistenceProvider with com.acme.PersistenceProvider;
…
}
The source code of the provider's module definition must contain the name of the provider’s implementation class.
Persistence provider jars may be installed or made available in the same ways as other service providers,
e.g. as extensions,oradded to the application classpath according to the guidelines in the JAR File
Specification or added to the application module path according to the guidelines in the Java Platform Module System specification.
Do you think this is fine, something should be corrected or is there a reason why this second part should not be added to JPA 2.2 MR?
Thank you,
--lukas[1]: https://java.net/jira/browse/JPA_SPEC-145
[2]: https://java.net/jira/browse/JPA_SPEC-146
Werner
Hi Werner,
Lukas,
Thanks for bringing that up.
I was wondering, if there is a common pattern all (Java EE) JSRs are supposed to follow for making the JSRs Java 9/Jigsaw compatible?
already got a module-info (at least for JSR 374 it was also you who created or last changed it;-)
Based on module naming by the JDK itself, should we take"java.<something>" as a module name to be the preferred name for both the JDK and all JSRs under jcp.org?
Or are there other preferences e.g. "javax.<something>" to match the Maven GroupId of most Java EE JSRs especially those by Oracle?see https://github.com/javaee/jsonp/blob/master/api/pom.xml for JSR 374.
A former EG Member of JSR 363 also asked this in our list and we discussed what would be a good module name there, but wanted to wait for official JCP guidance if possible.
Thanks and Regards,Werner