Running an External Scala Script in a Maven Build

You need to execute an external Scala script as a part of your Maven build.

Configure the script goal of the Maven Scala plugin and specify a Scala script in the scriptFile configuration parameter.

<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/maven-v4_0_0.xsd">
  <modelVersion>4.0.0</modelVersion>
  <groupId>org.sonatype.mhandbook</groupId>
  <artifactId>scala-script-ex</artifactId>
  <packaging>jar</packaging>
  <version>1.0-SNAPSHOT</version>
  <name>scala-script-ex</name>
  <dependencies>
    <dependency>
      <groupId>org.apache.maven</groupId>
      <artifactId>maven-model</artifactId>
      <version>2.2.0</version>
    </dependency>
    <dependency>
      <groupId>org.scala-lang</groupId>
      <artifactId>scala-library</artifactId>
      <version>2.7.3</version>
    </dependency>
    <dependency>
      <groupId>org.scala-tools</groupId>
      <artifactId>maven-scala-plugin</artifactId>
      <version>2.10.1</version>
    </dependency>
    <dependency>
      <groupId>org.scalaforge</groupId>
      <artifactId>scalax</artifactId>
      <version>0.1</version>
    </dependency>
  </dependencies>
  <build>
    <plugins>
      <plugin>
        <groupId>org.scala-tools</groupId>
        <artifactId>maven-scala-plugin</artifactId>
        <version>2.10.1</version>
        <executions>
          <execution>
            <id>scala-magic</id>
            <phase>prepare-package</phase>
            <goals>
              <goal>script</goal>
            </goals>
            <configuration>
              <keepGeneratedScript>true</keepGeneratedScript>
              <scriptFile>${basedir}/src/main/scala/CreateDeps.scala</scriptFile>
            </configuration>
          </execution>
        </executions>
      </plugin>
    </plugins>
  </build>
  <repositories>
    <repository>
      <id>scala-tools</id>
      <url>http://scala-tools.org/repo-releases/</url>
    </repository>
  </repositories>
</project>

In this example, the script is stored in an external file in ${basedir}/src/main/scala in CreateDeps.scala.

import java.io.{File,  PrintWriter, FileWriter};
import scalax.io.FileExtras;
import scala.collection.mutable.HashSet;
val outputDir = project.getBuild().getOutputDirectory();
val depsFile = new FileExtras( new File( outputDir, "deps.txt" ) );
val pw = depsFile.printWriter;
val depSet = new HashSet[String];
for( d <- project.getDependencies() ) {
  depSet += d.getGroupId + ":" + d.getArtifactId + ":" + d.getVersion;
}
pw.writeLines( depSet.toSeq );

This script creates a file named deps.txt in ${basedir}/target/classes which contains a list of the project's dependencies.

org.scalaforge:scalax:0.1
org.apache.maven:maven-model:2.2.0
org.scala-tools:maven-scala-plugin:2.10.1
org.scala-lang:scala-library:2.7.3

If you look in ${basedir}/target/.scalaScriptGen you can see that the Scala plugin creates a file named CreateDeps_1.scala that contains a class named CreateDeps_1.