| /* |
| * 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.nemo.runtime.executor.datatransfer; |
| |
| import org.apache.nemo.common.punctuation.Watermark; |
| |
| |
| /** |
| * An interface for tracking input watermarks among multiple input streams. |
| * --edge 1--> |
| * --edge 2--> watermarkManager --(emitWatermark)--> nextOperator |
| * --edge 3--> |
| */ |
| public interface InputWatermarkManager { |
| |
| /** |
| * This tracks the minimum input watermark among multiple input streams. |
| * This method is not a Thread-safe so the caller should synchronize it |
| * if multiple threads access this method concurrently. |
| * Ex) |
| * -- input stream1 (edge 1): ---------- ts: 3 ------------------ts: 6 |
| * ^^^ |
| * emit ts: 4 (edge 2) watermark at this time |
| * -- input stream2 (edge 2): ----------------- ts: 4------ |
| * ^^^ |
| * emit ts: 3 (edge 1) watermark at this time |
| * -- input stream3 (edge 3): ------- ts: 5 --------------- |
| * |
| * @param edgeIndex incoming edge index |
| * @param watermark watermark emitted from the edge |
| */ |
| void trackAndEmitWatermarks(int edgeIndex, Watermark watermark); |
| } |