[hibernate-issues] [Hibernate-JIRA] Created: (METAGEN-35) Generated meta model classes does not extend the super class' meta model.

[Joel Ringuette (JIRA)]

Generated meta model classes does not extend the super class' meta model.
-------------------------------------------------------------------------

                 Key: METAGEN-35
                 URL: http://opensource.atlassian.com/projects/hibernate/browse/METAGEN-35
             Project: Hibernate Metamodel Generator
          Issue Type: Bug
          Components: processor
    Affects Versions: 1.0.0.Final
         Environment: Maven 2.2.1, Hibernate 3.5.4, maven-processor-plugin 13.6
            Reporter: Joel Ringuette
            Assignee: Hardy Ferentschik


I'm currently using maven to build a project. I'm using org.bsc.maven.maven-processor-plugin plugin to generate the meta model. In my main source folder, I have a class annotated with @MappedSuperclass.

{code}
@MappedSuperclass
public abstract class BaseEntity
{
    // Entity id
    @Id
    @GeneratedValue
    private Long id;

    // some more code
}
{code}

In my test source folder, I have a class extending BaseEntity annotated with @Entity

{code}
@Entity()
public class Book extends BaseEntity
{
    private String name;

    @Column(unique = true)
    private String isbn;

    @ManyToOne(optional = false)
    private Author author;
    
    // some more code
}
{code}

When generating the meta model, the BaseEntity will generate BaseEntity_ and Book will generate Book_. The problem is that Book_ does not extend BaseEntity_

Here is my config of the plugin

{code:xml} 
<plugin>
    <groupId>org.bsc.maven</groupId>
    <artifactId>maven-processor-plugin</artifactId>
    <version>1.3.6</version>
    <executions>
        <execution>
            <id>process</id>
            <goals>
                <goal>process</goal>
            </goals>
            <phase>generate-sources</phase>
            <configuration>
                <!-- source output directory -->
                <outputDirectory>${project.build.sourceDirectory}</outputDirectory>
            </configuration>
        </execution>
        <execution>
            <id>process-test</id>
            <goals>
                <goal>process-test</goal>
            </goals>
            <phase>generate-test-sources</phase>
            <configuration>
                <!-- source output directory -->
                <outputDirectory>${project.build.testSourceDirectory}</outputDirectory>
                <compilerArguments>-Adebug=true</compilerArguments>
            </configuration>
        </execution>
    </executions>
    <dependencies>
        <dependency>
            <groupId>org.hibernate</groupId>
            <artifactId>hibernate-jpamodelgen</artifactId>
            <version>1.0.0.Final-Genia</version>
            <scope>compile</scope>
        </dependency>
    </dependencies>
</plugin>
{code} 

After looking at the code, the culprit seem to be org.hibernate.jpamodelgen.ClassWriter. In the method printClassDeclaration, we can see the following code:

{code}
if ( context.containsMetaEntity( superClassName )
        || context.containsMetaEmbeddable( superClassName ) ) {
    pw.print( " extends " + superClassName + "_" );
}
{code}

It assume the the super class meta model is generated at the same time as the extending class, which is not the case for test-compile and compile. I also assume that it does not work if you extend a class coming from a jar where the meta model was already generated.

To locally fix the problem, I changed the above code for:

{code}
if (((TypeElement) superClassElement).getAnnotation(Entity.class) != null
        || ((TypeElement) superClassElement).getAnnotation(MappedSuperclass.class) != null)
{
    pw.print(" extends " + superClassName + "_");
}
{code}

Since it's the first time I use annotation for code generation, I may not have fully understood the problem so feel free to correct me if the above fix is not the correct solution.

Regard,
Joel

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