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ASF GitHub Bot commented on FLINK-1977: --------------------------------------- Github user mbalassi commented on a diff in the pull request: https://github.com/apache/flink/pull/659#discussion_r29854598 --- Diff: flink-staging/flink-streaming/flink-streaming-core/src/main/java/org/apache/flink/streaming/api/functions/source/Source.java --- @@ -0,0 +1,87 @@ +/* + * 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.streaming.api.functions.source; + +import org.apache.flink.api.common.functions.Function; +import org.joda.time.Instant; + +import java.io.Serializable; + +/** + * Base interface for all stream data sources in Flink. The contract of a stream source + * is similar to an iterator - it is consumed as in the following pseudo code: + * + * <pre>{@code + * StreamSource<T> source = ...; + * Collector<T> out = ...; + * while (!source.reachedEnd()) { + * out.collect(source.next()); + * } + * } + * </pre> + * + * <b>Note about blocking behavior</b> + * <p>This implementations of the methods in the stream sources must have certain guarantees about + * blocking behavior. One of the two characteristics must be fulfilled.</p> + * <ul> + * <li>The methods must react to thread interrupt calls and break out of blocking calls with + * an {@link InterruptedException}.</li> + * <li>The method may ignore interrupt calls and/or swallow InterruptedExceptions, if it is guaranteed + * that the method returns quasi immediately irrespectively of the input. This is true for example + * for file streams, where the call is guaranteed to return after a very short I/O delay in + * the order of milliseconds.</li> + * </ul> + * + * @param <T> The type of the records produced by this source. + */ +public interface Source<T> extends Function, Serializable { --- End diff -- `StreamSource` or `SourceFunction`. > Rework Stream Operators to always be push based > ----------------------------------------------- > > Key: FLINK-1977 > URL: https://issues.apache.org/jira/browse/FLINK-1977 > Project: Flink > Issue Type: Improvement > Reporter: Aljoscha Krettek > Assignee: Aljoscha Krettek > > This is a result of the discussion on the mailing list. This is an excerpt > from the mailing list that gives the basic idea of the change: > I propose to change all streaming operators to be push based, with a > slightly improved interface: In addition to collect(), which I would > call receiveElement() I would add receivePunctuation() and > receiveBarrier(). The first operator in the chain would also get data > from the outside invokable that reads from the input iterator and > calls receiveElement() for the first operator in a chain. -- This message was sent by Atlassian JIRA (v6.3.4#6332)