gianm commented on code in PR #16790: URL: https://github.com/apache/druid/pull/16790#discussion_r1696280250
########## extensions-core/multi-stage-query/src/main/java/org/apache/druid/msq/shuffle/output/StageOutputReader.java: ########## @@ -0,0 +1,55 @@ +/* + * 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.druid.msq.shuffle.output; + +import com.google.common.util.concurrent.ListenableFuture; +import org.apache.druid.frame.channel.ReadableFrameChannel; +import org.apache.druid.msq.kernel.StageId; +import org.apache.druid.msq.shuffle.input.WorkerOrLocalInputChannelFactory; + +import java.io.Closeable; +import java.io.InputStream; + +/** + * Interface for remotely reading output channels for a particular stage. Each instance of this interface represents a + * stream from a single {@link org.apache.druid.msq.kernel.StagePartition} in + * {@link org.apache.druid.frame.file.FrameFile} format. + */ +public interface StageOutputReader extends Closeable +{ + /** + * Returns an {@link InputStream} starting from a particular point in the + * {@link org.apache.druid.frame.file.FrameFile}. Length of the stream is implementation-dependent; it may or may + * not go all the way to the end of the file. Zero-length stream indicates EOF. Any nonzero length means you should + * call this method again with a higher offset. + * + * @param offset offset into the frame file + * + * @see org.apache.druid.msq.exec.WorkerImpl#readChannel(StageId, int, long) + */ + ListenableFuture<InputStream> readRemotelyFrom(long offset); + + /** + * Returns a {@link ReadableFrameChannel} for local reading. + * + * @see WorkerOrLocalInputChannelFactory#openChannel(StageId, int, int) + */ + ReadableFrameChannel readLocally(); Review Comment: I have added this: ``` * It is implementation-dependent whether this method can be called multiple times. In particular, * {@link ChannelStageOutputReader#readLocally()} can only be called one time, but the implementations in * {@link FileStageOutputReader} and {@link NilStageOutputReader} can be called multiple times. ``` -- 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: commits-unsubscr...@druid.apache.org For queries about this service, please contact Infrastructure at: us...@infra.apache.org --------------------------------------------------------------------- To unsubscribe, e-mail: commits-unsubscr...@druid.apache.org For additional commands, e-mail: commits-h...@druid.apache.org
