KotlinConfigureMojo.java

package org.jetbrains.kotlin.maven;

import org.apache.maven.plugin.AbstractMojo;
import org.apache.maven.plugin.MojoExecutionException;
import org.apache.maven.plugin.MojoFailureException;
import org.apache.maven.plugins.annotations.Mojo;
import org.apache.maven.plugins.annotations.Parameter;
import org.apache.maven.project.MavenProject;

import java.io.File;

/**
 * Sets up common configuration needed for a kotlin project. Adds {@code src/main/kotlin} and {@code src/test/kotlin} as
 * source (if the exist). Removes {@code src/main/java} and {@code src/test/java} if they do not.
 */
@Mojo(name = "configure")
public class KotlinConfigureMojo extends AbstractMojo {

    @Parameter(property = "project")
    private MavenProject project;

    @Parameter(defaultValue = "${project.basedir}/src/main/kotlin", readonly = true)
    private String kotlinSourceDirectory;

    @Parameter(defaultValue = "${project.build.sourceDirectory}", readonly = true)
    private String javaSourceDirectory;

    @Parameter(defaultValue = "${project.basedir}/src/test/kotlin", readonly = true)
    private String kotlinTestSourceDirectory;

    @Parameter(defaultValue = "${project.build.testSourceDirectory}", readonly = true)
    private String javaTestSourceDirectory;

    @Override
    public void execute() throws MojoExecutionException, MojoFailureException {

        // remove the default java source dirs if they do not exist
        // Do NOT mess with any of the other source roots other plugins may add
        if (!new File(javaSourceDirectory).exists()) {
            project.getCompileSourceRoots().remove(javaSourceDirectory);
        }
        if (!new File(javaTestSourceDirectory).exists()) {
            project.getTestCompileSourceRoots().remove(javaTestSourceDirectory);
        }

        // add the kotlin ones if needed
        if (new File(kotlinSourceDirectory).exists()) {
            project.addCompileSourceRoot(kotlinSourceDirectory);
        }

        if (new File(kotlinTestSourceDirectory).exists()) {
            project.addTestCompileSourceRoot(kotlinTestSourceDirectory);
        }

        getLog().debug("Configured sources: " + project.getCompileSourceRoots());
        getLog().debug("Configured test sources: " + project.getTestCompileSourceRoots());
    }
}