bozhang2820 commented on a change in pull request #33763: URL: https://github.com/apache/spark/pull/33763#discussion_r698243792
########## File path: sql/core/src/main/scala/org/apache/spark/sql/execution/streaming/AvailableNowDataStreamWrapper.scala ########## @@ -0,0 +1,85 @@ +/* + * 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.sql.execution.streaming + +import org.apache.spark.internal.Logging +import org.apache.spark.sql.connector.read.streaming.{MicroBatchStream, ReadLimit, SparkDataStream, SupportsAdmissionControl, SupportsTriggerAvailableNow} +import org.apache.spark.sql.connector.read.streaming + +/** + * This class wraps a [[SparkDataStream]] and makes it support Trigger.AvailableNow, by + * overriding its [[latestOffset]] method to always return the latest offset when the method is + * first called. It is as if there is no new data coming in from the source after the first + * [[latestOffset]] call. + */ +class AvailableNowDataStreamWrapper(val delegate: SparkDataStream) + extends SparkDataStream with SupportsTriggerAvailableNow with Logging { + + private var fetchedOffset: Option[streaming.Offset] = _ + + override def initialOffset(): streaming.Offset = delegate.initialOffset() + + override def deserializeOffset(json: String): streaming.Offset = delegate.deserializeOffset(json) + + override def commit(end: streaming.Offset): Unit = delegate.commit(end) + + override def stop(): Unit = delegate.stop() + + override def prepareForTriggerAvailableNow(): Unit = {} Review comment: Turned out `startOffset` is not needed in `prepareForTriggerAvailableNow`. See the latest code update. -- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. To unsubscribe, e-mail: [email protected] For queries about this service, please contact Infrastructure at: [email protected] --------------------------------------------------------------------- To unsubscribe, e-mail: [email protected] For additional commands, e-mail: [email protected]
