// Mirrors
    List<Mirror> getMirrors();

    MavenExecutionRequest setMirrors(List<Mirror> mirrors);

    MavenExecutionRequest addMirror(Mirror mirror);

    // Plugin groups
    List<String> getPluginGroups();

    MavenExecutionRequest setPluginGroups(List<String> pluginGroups);

    MavenExecutionRequest addPluginGroup(String pluginGroup);

    MavenExecutionRequest addPluginGroups(List<String> pluginGroups);