StefanRRichter commented on a change in pull request #8467: [FLINK-12535][network] Make CheckpointBarrierHandler non-blocking URL: https://github.com/apache/flink/pull/8467#discussion_r285497172
########## File path: flink-runtime/src/main/java/org/apache/flink/runtime/io/AsyncDataInput.java ########## @@ -0,0 +1,50 @@ +/* + * 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.flink.runtime.io; + +import java.util.concurrent.CompletableFuture; + +/** + * Interface defining couple of essential methods for asynchronous and non blocking data polling. + */ +public interface AsyncDataInput<T> { + CompletableFuture<?> AVAILABLE = CompletableFuture.completedFuture(null); + + /** + * Poll the next element. + * + * @return If the {@link T} is an {@code Optional}: + * 1. return {@code Optional.of(element)} - next returned element. {@code Optional.empty()} will + * be returned if there is no data to return or if {@link #isFinished()} returns true. + * otherwise: + * 2. next element or null if there is no data to return or if {@link #isFinished()} returns true. + */ + T pollNext() throws Exception; + + /** + * @return true if end of input was reached, false otherwise. + */ + boolean isFinished(); + + /** + * @return a future that is completed if there are more records available. If there are more + * records available immediately, {@link #AVAILABLE} should be returned. Previously returned + * not completed futures should become completed once there are more records available. Review comment: The interface does never talk about `records`, so I would rather go with `more input available` ---------------------------------------------------------------- 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. For queries about this service, please contact Infrastructure at: us...@infra.apache.org With regards, Apache Git Services
