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Aether/Using Aether in Maven Plugins

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For the time being, this article actually refers to Sonatype Aether, i.e. the predecessor of Eclipse Aether. While the artifact coordinates and class names mentioned below differ slightly from those of Eclipse Aether, the general concept for usage of Aether will remain the same once Maven has adopted Eclipse Aether.


Apache Maven 3.0.x uses Aether for repository tasks and Maven plugins that target Maven 3.x can do so as well. To start, you likely want to add the following dependencies to your plugin POM:

<project>
  ...
  <prerequisites>
    <maven>3.0</maven>
  </prerequisites>
 
  <dependencies>
    <dependency>
      <!-- required in all cases -->
      <groupId>org.sonatype.aether</groupId>
      <artifactId>aether-api</artifactId>
      <version>1.8</version>
    </dependency>
    <dependency>
      <!-- optional helpers, might be superfluous depending on your use case -->
      <groupId>org.sonatype.aether</groupId>
      <artifactId>aether-util</artifactId>
      <version>1.8</version>
    </dependency>
    ...
  </dependencies>
  ...
</project>

Note: At runtime, the actual version of aether-api being used is enforced by the Maven core, just like other Maven APIs. So be sure to compile/test your plugin against the version of aether-api that is used by the mininum version of Maven that your plugin wants to support.

Next, in your mojo source, you would need to grab the repository related components and parameters:

import org.sonatype.aether.RepositorySystem;
import org.sonatype.aether.RepositorySystemSession;
import org.sonatype.aether.repository.RemoteRepository;
...
 
public MyMojo extends AbstractMojo
{ 
 
    /**
     * The entry point to Aether, i.e. the component doing all the work.
     * 
     * @component
     */
    private RepositorySystem repoSystem;
 
    /**
     * The current repository/network configuration of Maven.
     * 
     * @parameter default-value="${repositorySystemSession}"
     * @readonly
     */
    private RepositorySystemSession repoSession;
 
    /**
     * The project's remote repositories to use for the resolution of project dependencies.
     * 
     * @parameter default-value="${project.remoteProjectRepositories}"
     * @readonly
     */
    private List<RemoteRepository> projectRepos;
 
    /**
     * The project's remote repositories to use for the resolution of plugins and their dependencies.
     * 
     * @parameter default-value="${project.remotePluginRepositories}"
     * @readonly
     */
    private List<RemoteRepository> pluginRepos;
 
    // Your other mojo parameters and code here
    ...
}

Usually, you need only projectRepos or pluginRepos depending on the nature of artifacts your plugin is dealing with, so the other plugin parameter would be superfluous in that case. But in general, the bits shown above should give you all handles that you need to work with Aether from within a Maven plugin.