s3_delete_multiple_objects.scala

def deleteMuliS3Objects(bucket: String, prefix: String): Unit = {
  import scala.collection.JavaConverters._
  import com.amazonaws.AmazonServiceException
  import com.amazonaws.SdkClientException
  import com.amazonaws.services.s3.AmazonS3
  import com.amazonaws.services.s3.AmazonS3ClientBuilder
  import com.amazonaws.services.s3.model.DeleteObjectsRequest
  import com.amazonaws.services.s3.model.DeleteObjectsRequest.KeyVersion
  
  val s3Client: AmazonS3 = AmazonS3ClientBuilder.standard().build();

  try{
    // a bad way to map on a java list -- convert to scala list and then back to java because delelteobjectreqeuest 
    // does not accept scala list as it's input
    val keyList: List[KeyVersion] = s3Client.listObjects(bucket, prefix)
                                            .getObjectSummaries()
                                            .asScala.toList.map(item => new KeyVersion(item.getKey()))
    if (keyList.length > 0){ 
      val delObjRes = s3Client.deleteObjects(new DeleteObjectsRequest(bucket)
                                            .withKeys(keyList.asJava))
      
      val successfulDeletes = delObjRes.getDeletedObjects().size()
      println(successfulDeletes)
    } else {
      println(s"No objects to delete in $bucket/$prefix")
    }
  } catch {
    case e: AmazonServiceException => e.printStackTrace()
    case e: SdkClientException => e.printStackTrace()
  }
}