Metamodel generation in Eclipse

Nik · **Joined:** Wed Oct 15, 2003 4:40 pm **Posts:** 67

Hi,

I'm using the latest jpamodelgen and jpa2 with a m2eclipse project in Eclipse which I have set up according to the documentation. The strange thing is that I get the source files generated fine under /target/metamodel but they are not compiled even if that folder is added as a source folder and I have all autobuilding on etc. This results in the that Foo_ classes are not resolved in the code. If I change something in the generated file, it is automagically compiled. This could of course be a eclipse/me2eclipse issue but I thought you guys could have some insight.

Thanks in advance,
-Nik

leden · **Joined:** Sat Jul 17, 2010 10:33 am **Posts:** 4

The same problem here. I also posted this on stackoverflow but, again, no responses.
I wonder how all those Eclipse users use that model generator...

tyoung · **Joined:** Thu Jan 22, 2009 6:22 pm **Posts:** 5

I had real fun getting the metamodel generator, eclipse, and maven to coordinate on this. Here is what you need to do when using m2eclipse:

Add the following to your POM file:

Code:

<build>
      <plugins>
         <plugin>
            <groupId>org.codehaus.mojo</groupId>
            <artifactId>build-helper-maven-plugin</artifactId>
            <version>1.3</version>
            <executions>
               <execution>
                  <id>add-source</id>
                  <phase>generate-sources</phase>
                  <goals>
                     <goal>add-source</goal>
                  </goals>
                  <configuration>
                     <sources>
                        <source>src/generated/java</source>
                     </sources>
                  </configuration>
               </execution>
            </executions>
         </plugin>
         <plugin>
            <groupId>org.apache.maven.plugins</groupId>
            <artifactId>maven-compiler-plugin</artifactId>
            <version>2.0.2</version>
            <configuration>
               <source>1.6</source>
               <target>1.6</target>
               <compilerArguments>
                  <processor>org.hibernate.jpamodelgen.JPAMetaModelEntityProcessor</processor>
               </compilerArguments>
            </configuration>
         </plugin>
      </plugins>
   </build>

Notice that I am generating sources to the directory src/generated/java. You don't want even generated source code to go to target. Only the compiled classes should go to target.

Open the project properties in eclipse. Go to Java Compiler/Annotation Processing

Enable annotation processing and set the generated source directory to src/generated/java.

Under factory path, you will need to reference the metamodel jar and any dependencies.

As far as I can tell, there is no way to get maven to generate this configuration.

Now, right click on the project and select Maven/Update Project Configuration. This should add a new source directory to you your project called generated/java. You should see your metamodel there.

You do not want to use your main/java directory as the target of the metamodel generator as it will delete all of your source files!

Ted Young

leden · **Joined:** Sat Jul 17, 2010 10:33 am **Posts:** 4

Now I get the following error:

Quote:

Build errors for (myproject); org.apache.maven.ProjectBuildFailureException: Build for project: ... failed during execution of mojo: org.apache.maven.plugins:maven-compiler-plugin:2.0.2:compile

I also tried the other way, suggested here:
http://docs.jboss.org/hibernate/jpamodelgen/1.0/reference/en-US/html_single/#maven-processor-plugin
but I get the same error. Any ideas?
Suprisingly, if I build using "mvn compile" (with either build configuration), there is no error.

Hopefully, I found a workaround which for some reason works only when using maven-annotation plugin. After I got the error, I just right click on project and then click
Maven -> Update Project Configuration.
This is only required after a clean-up of the project, so I can live with it for the time being.

Anyway, thanks for the detailed info.

Merllinas · **Joined:** Wed Nov 03, 2010 2:36 pm **Posts:** 9

Hello,
I'm also using jpamodelgen and JPA2 but I have a problem..
My project contains multiple packages and other classes without annotations i.e. @Entity and when processor tries to process such classes I get exception in eclipse:

Code:

Internal compiler error: java.lang.NoClassDefFoundError: javax/persistence/Entity at org.hibernate.jpamodelgen.JPAMetaModelEntityProcessor.isJPAEntity(JPAMetaModelEntityProcessor.java:188)   PTMUtils.java   /ptm-model/src/main/java/com/ptm/commons   line 0   Java Problem

is there a way to specify package(s) that JPAMetaModelEntityProcessor should use?
Or how to exclude packages?

Merllinas · **Joined:** Wed Nov 03, 2010 2:36 pm **Posts:** 9

My bad.
It not JPAMetaModelEntityProcessor fault. persistence-api just wasn't in the classpath. I added library in annotation processoing factory path and vualia.

francois · **Joined:** Wed Nov 10, 2010 7:13 am **Posts:** 2

Hi there, I'm trying to use the hibernate metamodel generator with Eclipse (helios).
I've setup the generated source directory location to "src" since I want generated classes be integrated to the svn, I don't want to integrate this process to maven.

I'm actually able to generate metamodel classes as expected, BUT, I can't make them be recognized by eclipse as new to add into the version control. It's like all generated classes are automatically ignored (svn:ignore).
When I look to the "Synchronize" view, I can't see them...

Can somebody tell me what's I'm doing wrong?

Thanks

Merllinas · **Joined:** Wed Nov 03, 2010 2:36 pm **Posts:** 9

It might be that there is a filter in SVN that ignores that pattern. I'm pretty sure that it's because of underscore. Try checking Team > Ignored resources settings.

francois · **Joined:** Wed Nov 10, 2010 7:13 am **Posts:** 2

@Merllinas

I've checked up the Team->Ignored Resources settings, can't see any patterns that could exclude them.
The funny thing is, when I manually create a class with the name and contents (copy and past) as the generated one, I can version it...

Cheers,

Kai · **Posted:** Fri Nov 12, 2010 11:12 am

Hi!

I just played around with the generator. Perhaps somebody can give me some answers to my questions.
Where I get the JAR of the generator?
The ZIP or TGZ only contains the source code: http://sourceforge.net/projects/hiberna ... amodelgen/
Here I found a snapshot: http://snapshots.jboss.org/maven2/org/h ... -SNAPSHOT/

Within Eclipse mainly the generation works, but not always. It seems that an open metaclass file Car_ avoids updating it after saving the entity Car.java.
Anybody have similar experience or a fix for it?

adamtarshis · **Joined:** Mon May 08, 2006 1:01 pm **Posts:** 5

To get the hibernate-jpamodelgen jar through maven, include the following repository in your pom:
https://repository.jboss.org/nexus/cont ... s/releases

Make sure your version is set to 1.1.1.Final

For example:

Code:

<plugin>
             <groupId>org.bsc.maven</groupId>
             <artifactId>maven-processor-plugin</artifactId>
             <version>1.3.7</version>
             <executions>
                 <execution>
                     <id>process</id>
                     <goals>
                         <goal>process</goal>
                     </goals>
                     <phase>process-sources</phase>
                 </execution>
             </executions>
            <dependencies>
                 <dependency>
                     <groupId>org.hibernate</groupId>
                     <artifactId>hibernate-jpamodelgen</artifactId>
                     <version>1.1.1.Final</version>
                     <scope>compile</scope>
                 </dependency>
             </dependencies>             
         </plugin>      

mgbowman · **Joined:** Wed Jan 05, 2011 6:43 am **Posts:** 1

francois wrote:

I'm actually able to generate metamodel classes as expected, BUT, I can't make them be recognized by eclipse as new to add into the version control. It's like all generated classes are automatically ignored (svn:ignore).
When I look to the "Synchronize" view, I can't see them...

They are being marked as Derived (they are being generated). You can view this in the properies dialog of the _.java files. I don't know if you able to configure this somehow but my guess would be no. It does make sense to mark generated java files as such.

I too have the files being generated into my src/main/java directory and after upgrading to 1.1.1.Final 99.9% of my sources using the Entity_.java metamodel classes don't have errors. I was using 1.0.0.Final and it wasn't reporting the generated classes to the Eclipse JDT compiler, hence the classes referencing the metamodel were having unresolved type errors on a project clean.

Now when I do a project clean, I'm stuck with 1 class which has unresolved type errors. It seems there may yet still be a bug in either jpamodelgen or the way the eclipse annotation processing is done...

For now, I'm stuck with making a trivial change in the 1 class with errors to get it to do an incremental build to clear the errors. I'll report back if I able to figure out exactly what's going on.

Anyone out there having similar issues?

--mgbowman

psimun · **Joined:** Fri Feb 04, 2011 4:47 am **Posts:** 1

I assume that hibernate meta-model entity processor is generating sources in the last processor round. This is not recommended way and leads exactly to the problem that you have. Explanation is here: http://code.google.com/p/acris/wiki/Cod ... all_Rounds

So the my advise is to generate sources in regular processing rounds and final round should be used just for notification that processing is over or something like that.

I did not study the annotation processor into the details but this should be the problem:
if ( roundEnvironment.processingOver() ) {
if ( !context.isPersistenceUnitCompletelyXmlConfigured() ) {
context.logMessage( Diagnostic.Kind.OTHER, "Last processing round." );
--->>> createMetaModelClasses(); <<<--- THIS GENERATE SOURCE FILE in the last processing round and causes the problems
context.logMessage( Diagnostic.Kind.OTHER, "Finished processing" );
}
return ALLOW_OTHER_PROCESSORS_TO_CLAIM_ANNOTATIONS;
}
}

Hopefully this helps you.

MikeHT · **Joined:** Sat Dec 29, 2012 2:38 pm **Posts:** 5

tyoung wrote:

I had real fun getting the metamodel generator, eclipse, and maven to coordinate on this. Here is what you need to do when using m2eclipse:

Add the following to your POM file:

[code]
<build>
<plugins>
<plugin>
<groupId>org.codehaus.mojo</groupId>
<artifactId>build-helper-maven-plugin</artifactId>
<version>1.3</version>
<executions>
<execution>
<id>add-source</id>
<phase>generate-sources</phase>
<goals>
<goal>add-source</goal>
</goals>
<configuration>
<sources>
<source>src/generated/java</source>
</sources>
</configuration>
</execution>
</executions>
</plugin>
.
.
.

Notice that I am generating sources to the directory src/generated/java. You don't want even generated source code to go to target. Only the compiled classes should go to target.

Open the project properties in eclipse. Go to Java Compiler/Annotation Processing

Enable annotation processing and set the generated source directory to src/generated/java.

Under factory path, you will need to reference the metamodel jar and any dependencies.

As far as I can tell, there is no way to get maven to generate this configuration.

Now, right click on the project and select Maven/Update Project Configuration. This should add a new source directory to you your project called generated/java. You should see your metamodel there.

You do not want to use your main/java directory as the target of the metamodel generator as it will delete all of your source files!

Ted Young

Ted,

I revisited this and got it to work in my project . Thanks
Mike