maven-processor-plugin to ignore undefined symbols - maven

Question

I've JPA 2 maven project and I want to process sources to have the static meta model. What I did I took JBoss' static meta model processor and set it up to run during generate-sources phase. Now, obviously I have some classes that reference the meta model and compilation itself goes fine. But maven-processor-plugin itself generates errors complaining that it can't find symbols from meta model like this:
[INFO] --- maven-processor-plugin:2.2.4:process (process) # ng-grid-java ---
[ERROR] diagnostic: c:\...\service\position\PositionSpecifications.java:13: cannot find symbol
symbol : class Position_
Which is logical because it actually generates these classes, but is not right since it brings errors to an otherwise correct project. Or maybe I'm using it wrong? Am I missing something?
Update: I have been able to inhibit the error output by using configuration parameter outputDiagnostics but I'm not sure that's the right way.

Answer 1

The solution could be adding the generated classes to project classpath using the build-helper-maven-plugin, as follows:
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
<modelVersion>4.0.0</modelVersion>
<parent>
<artifactId>artifactId</artifactId>
<groupId>groupId</groupId>
<version>1.0.0-SNAPSHOT</version>
</parent>
<artifactId>jpa-metamodel-generation</artifactId>
<dependencies>
<!-- Hibernate JPA metamodel generator -->
<dependency>
<groupId>org.hibernate</groupId>
<artifactId>hibernate-jpamodelgen</artifactId>
<version>1.2.0.Final</version>
<scope>provided</scope>
<exclusions>
<exclusion>
<groupId>org.hibernate.javax.persistence</groupId>
<artifactId>hibernate-jpa-2.0-api</artifactId>
</exclusion>
</exclusions>
</dependency>
</dependencies>
<build>
<plugins>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-compiler-plugin</artifactId>
<configuration>
<compilerArgument>-proc:none</compilerArgument>
</configuration>
</plugin>
<!-- Plugin to generate JPA metamodel -->
<plugin>
<groupId>org.bsc.maven</groupId>
<artifactId>maven-processor-plugin</artifactId>
<version>2.0.5</version>
<executions>
<execution>
<id>process</id>
<goals>
<goal>process</goal>
</goals>
<phase>process-sources</phase>
<configuration>
<outputDirectory>${project.build.directory}/metamodel</outputDirectory>
<processors>
<processor>org.hibernate.jpamodelgen.JPAMetaModelEntityProcessor</processor>
</processors>
</configuration>
</execution>
</executions>
</plugin>
<!-- Build helper plugin to add generated sources to classpath -->
<plugin>
<groupId>org.codehaus.mojo</groupId>
<artifactId>build-helper-maven-plugin</artifactId>
<version>1.7</version>
<executions>
<execution>
<id>add-source</id>
<phase>generate-sources</phase>
<goals>
<goal>add-source</goal>
</goals>
<configuration>
<sources>
<source>${project.build.directory}/metamodel</source>
</sources>
</configuration>
</execution>
</executions>
</plugin>
</plugins>
</build>
</project>

Answer 2

I have setted the phase-s of the plugins like:
build-helper-maven-plugin --> <phase>process-sources</phase>
and
maven-processor-plugin --> <phase>compile</phase>