Github user brkyvz commented on a diff in the pull request: https://github.com/apache/spark/pull/18029#discussion_r137343555 --- Diff: external/kinesis-asl/src/main/scala/org/apache/spark/streaming/kinesis/InitialPosition.scala --- @@ -0,0 +1,104 @@ +/* + * Licensed to the Apache Software Foundation (ASF) under one or more + * contributor license agreements. See the NOTICE file distributed with + * this work for additional information regarding copyright ownership. + * The ASF licenses this file to You under the Apache License, Version 2.0 + * (the "License"); you may not use this file except in compliance with + * the License. You may obtain a copy of the License at + * + * http://www.apache.org/licenses/LICENSE-2.0 + * + * Unless required by applicable law or agreed to in writing, software + * distributed under the License is distributed on an "AS IS" BASIS, + * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. + * See the License for the specific language governing permissions and + * limitations under the License. + */ +package org.apache.spark.streaming.kinesis + +import java.util.Date + +import com.amazonaws.services.kinesis.clientlibrary.lib.worker.InitialPositionInStream + +/** + * Trait for Kinesis's InitialPositionInStream. + * This will be overridden by more specific types. + */ +sealed trait InitialPosition { + val initialPositionInStream: InitialPositionInStream +} + +/** + * Case object for Kinesis's InitialPositionInStream.LATEST. + */ +case object Latest extends InitialPosition { + val instance: InitialPosition = this + override val initialPositionInStream: InitialPositionInStream + = InitialPositionInStream.LATEST +} + +/** + * Case object for Kinesis's InitialPositionInStream.TRIM_HORIZON. + */ +case object TrimHorizon extends InitialPosition { + val instance: InitialPosition = this + override val initialPositionInStream: InitialPositionInStream + = InitialPositionInStream.TRIM_HORIZON +} + +/** + * Case object for Kinesis's InitialPositionInStream.AT_TIMESTAMP. + */ +case class AtTimestamp(timestamp: Date) extends InitialPosition { + val instance: InitialPosition = this + override val initialPositionInStream: InitialPositionInStream + = InitialPositionInStream.AT_TIMESTAMP +} + +/** + * Companion object for InitialPosition that returns + * appropriate version of InitialPositionInStream. + */ +object InitialPosition { + + /** + * An instance of Latest with InitialPositionInStream.LATEST. + * @return [[Latest]] + */ + val latest: InitialPosition = Latest --- End diff -- Good question. They used to be just classes. Since we couldn't have a nice way for using a `case object` in Java, you need to add a $ after the classname, e.g. `TrimHorizon$`, we decided to go the class syntax'y way. In scala, this still allows you to use the class with `KinesisInitialPosition.Latest` for example.
--- --------------------------------------------------------------------- To unsubscribe, e-mail: reviews-unsubscr...@spark.apache.org For additional commands, e-mail: reviews-h...@spark.apache.org