> On May 4, 2017, at 10:47 AM, Lukas Jungmann <lukas.jungmann_at_oracle.com> wrote:
>
> Hi,
>
> On 5/4/17 1:21 AM, Linda DeMichiel wrote:
>> Hi,
>>
>> Since Java EE 8 only requires Java SE 8, JPA 2.2 shouldn't explicitly
>> define anything related to Java SE 9 modules. (I.e., the
>> italicized text should not be included in the spec.)
>
> I agree; it's inline with my proposal to 1) (...don't do it now, target milestone for JPA_SPEC-145 has been changed from 2.2 to TBD)
>
>>
>> Also, with regard to the second item below (Section 9.2), it isn't
>> clear how the ServiceLoader facility is intended to be used.
>> Is this intended as a replacement for the requirements in section 9.3
>> (Determining the Available Persistence Providers)?
>> Or is it only intended as a replacement for the behavior of the
>> default PersistenceProviderResolver in determining the persistence
>> providers?
> My intention is to replace direct reference to service provider configuration file and in turn to JAR File specification (and following paragraph which looks like a slightly modified copy of ServiceLoader javadoc) in 9.2 with a direct reference to ServiceLoader itself, which, I think, would make the 'should' statement in " A persistence provider implementation running in a Java SE environment should also act as a service provider..." a bit more general - not constrained by availability of META-INF/services/javax.persistence.spi.PersistenceProvider but constrained directly with what ServiceLoader defines and expects. So given SE 8 is a base, it's only wording what I propose to change, behaviour of what is in 9.2/9.3 should remain the same (... unless I overlooked something, what can easily happen…).
I had to do the same for JDBC,
http://download.java.net/java/jdk9/docs/api/java/sql/DriverManager.html <
http://download.java.net/java/jdk9/docs/api/java/sql/DriverManager.html> , and changed the wording to:
Service providers of the java.sql.Driver class, that are loaded via the service-provider loading <
http://download.java.net/java/jdk9/docs/api/java/util/ServiceLoader.html#load-java.lang.Class-java.lang.ClassLoader-java.lang.Module-> mechanism.
This allows for support for JDK 8 service providers as well as modules which are service providers.
>
> Does it make more sense now?
>
> Thanks,
> --lukas
>>
>> thanks,
>>
>> -Linda
>>
>>
>> On 5/3/17, 9:13 AM, Lukas Jungmann wrote:
>>> 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 configuration file as described in the JAR File Specification. The Persistence
>>> bootstrap class should use ServiceLoader facility to locate all available provider implementations.
>>>
>>> The provider configuration file serves 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, or added 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 <https://java.net/jira/browse/JPA_SPEC-145>
>>> [2]: https://java.net/jira/browse/JPA_SPEC-146 <https://java.net/jira/browse/JPA_SPEC-146>
>>
>
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<
http://oracle.com/us/design/oracle-email-sig-198324.gif>Lance Andersen| Principal Member of Technical Staff | +1.781.442.2037
Oracle Java Engineering
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Lance.Andersen_at_oracle.com <mailto:Lance.Andersen_at_oracle.com>
