androidJavadoc {
  // variantFilter takes a closure that received an Android variant as parameter.
  // Return true to generate javadoc task for this variant, false to do nothing
  // This is the default closure :
  variantFilter { variant ->
    if (variant) {
      return true
    } else {
      return false
    }
  }

  // taskNameTransformer takes a closure to customise the task name.
  // Task name pattern is "generate${taskNameTransformer(variant).capitalize()}Javadoc"
  // This is the default implementation :
  taskNameTransformer { variant ->
    variant.name
  }

  // outputDir return the documentation output dir
  // Default implementation :
  outputDir = { Project project ->
    "${project.buildDir}/docs/javadoc/"
  }
}