Add maven-build-classpath to plugin execution classpath

Found the answer!

OK , Pascal is right , here it is for the foundation!!

So here is the cleanest way ( as far as i know ) to add the compile classpath to the execution of you plugin.

Here are some code samples from my code-gen plugin, that is actually generating some template code based on the code compiled. So I needed first the code compiled, then analyzed, generate some code, and then compiled again.

Use @configurator in the Mojo class:

/**
 * @goal generate
 * @phase process-classes
 * @configurator include-project-dependencies
 * @requiresDependencyResolution compile+runtime
 */
public class CodeGenMojo
        extends AbstractMojo
{
    public void execute()
            throws MojoExecutionException
    {
         // do work....   
    }
}

Please pay attention to the @configurator line in the javadoc header, it is essetial for the plexus IOC container and is not just another comment line.

The implementation of the include-project-dependencies configurator. There is this very nice class that I took from some Brian Jackson, add it to the source of your plugin.

/**
 * A custom ComponentConfigurator which adds the project's runtime classpath elements
 * to the
 *
 * @author Brian Jackson
 * @since Aug 1, 2008 3:04:17 PM
 *
 * @plexus.component role="org.codehaus.plexus.component.configurator.ComponentConfigurator"
 *                   role-hint="include-project-dependencies"
 * @plexus.requirement role="org.codehaus.plexus.component.configurator.converters.lookup.ConverterLookup"
 *                   role-hint="default"
 */
public class IncludeProjectDependenciesComponentConfigurator extends AbstractComponentConfigurator { 

    private static final Logger LOGGER = Logger.getLogger(IncludeProjectDependenciesComponentConfigurator.class);

    public void configureComponent( Object component, PlexusConfiguration configuration,
                                    ExpressionEvaluator expressionEvaluator, ClassRealm containerRealm,
                                    ConfigurationListener listener )
        throws ComponentConfigurationException {

        addProjectDependenciesToClassRealm(expressionEvaluator, containerRealm);

        converterLookup.registerConverter( new ClassRealmConverter( containerRealm ) );

        ObjectWithFieldsConverter converter = new ObjectWithFieldsConverter();

        converter.processConfiguration( converterLookup, component, containerRealm.getClassLoader(), configuration,
                                        expressionEvaluator, listener );
    }

    private void addProjectDependenciesToClassRealm(ExpressionEvaluator expressionEvaluator, ClassRealm containerRealm) throws ComponentConfigurationException {
        List<String> runtimeClasspathElements;
        try {
            //noinspection unchecked
            runtimeClasspathElements = (List<String>) expressionEvaluator.evaluate("${project.runtimeClasspathElements}");
        } catch (ExpressionEvaluationException e) {
            throw new ComponentConfigurationException("There was a problem evaluating: ${project.runtimeClasspathElements}", e);
        }

        // Add the project dependencies to the ClassRealm
        final URL[] urls = buildURLs(runtimeClasspathElements);
        for (URL url : urls) {
            containerRealm.addConstituent(url);
        }
    }

    private URL[] buildURLs(List<String> runtimeClasspathElements) throws ComponentConfigurationException {
        // Add the projects classes and dependencies
        List<URL> urls = new ArrayList<URL>(runtimeClasspathElements.size());
        for (String element : runtimeClasspathElements) {
            try {
                final URL url = new File(element).toURI().toURL();
                urls.add(url);
                if (LOGGER.isDebugEnabled()) {
                    LOGGER.debug("Added to project class loader: " + url);
                }
            } catch (MalformedURLException e) {
                throw new ComponentConfigurationException("Unable to access project dependency: " + element, e);
            }
        }

        // Add the plugin's dependencies (so Trove stuff works if Trove isn't on
        return urls.toArray(new URL[urls.size()]);
    }

}

Here is the build part of my plugin that you will have to add.

<modelVersion>4.0.0</modelVersion>
<groupId>com.delver</groupId>
<artifactId>reference-gen-plugin</artifactId>
<name>Reference Code Genration Maven Plugin</name>

<packaging>maven-plugin</packaging>
<version>1.2</version>

<url>http://maven.apache.org</url>

<properties>
    <maven.version>2.2.1</maven.version>
</properties>

<build>
    <plugins>
        <plugin>
            <groupId>org.codehaus.plexus</groupId>
            <artifactId>plexus-maven-plugin</artifactId>
            <executions>
                <execution>
                    <goals>
                        <goal>descriptor</goal>
                    </goals>
                </execution>
            </executions>
        </plugin>
    </plugins>
</build>
<dependencies>

    <dependency>
        <groupId>org.apache.maven</groupId>
        <artifactId>maven-artifact</artifactId>
        <version>${maven.version}</version>
    </dependency>
    <dependency>
        <groupId>org.apache.maven</groupId>
        <artifactId>maven-plugin-api</artifactId>
        <version>${maven.version}</version>
    </dependency>
    <dependency>
        <groupId>org.apache.maven</groupId>
        <artifactId>maven-project</artifactId>
        <version>${maven.version}</version>
    </dependency>
    <dependency>
        <groupId>org.apache.maven</groupId>
        <artifactId>maven-model</artifactId>
        <version>${maven.version}</version>
    </dependency>
    <dependency>
        <groupId>org.apache.maven</groupId>
        <artifactId>maven-core</artifactId>
        <version>2.0.9</version>
    </dependency>

</dependencies>

Here is the pom.xml of the plugin for these who need it. Should compile wihtout a problem now. ( something wrong with the header, so ignore it )

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