| /* |
| * 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.task; |
| |
| import org.apache.nemo.common.ir.OutputCollector; |
| import org.apache.nemo.common.ir.Readable; |
| import org.apache.nemo.common.ir.vertex.SourceVertex; |
| import org.apache.nemo.common.punctuation.Finishmark; |
| import org.apache.nemo.common.punctuation.Watermark; |
| |
| import java.util.concurrent.Executors; |
| import java.util.concurrent.ScheduledExecutorService; |
| import java.util.concurrent.TimeUnit; |
| |
| /** |
| * Fetches data from a data source. |
| */ |
| class SourceVertexDataFetcher extends DataFetcher { |
| private final Readable readable; |
| private long boundedSourceReadTime = 0; |
| private static final long WATERMARK_PERIOD = 1000; // ms |
| private final ScheduledExecutorService watermarkTriggerService; |
| private boolean watermarkTriggered = false; |
| private final boolean bounded; |
| |
| SourceVertexDataFetcher(final SourceVertex dataSource, |
| final Readable readable, |
| final OutputCollector outputCollector) { |
| super(dataSource, outputCollector); |
| this.readable = readable; |
| this.readable.prepare(); |
| this.bounded = dataSource.isBounded(); |
| |
| if (!bounded) { |
| this.watermarkTriggerService = Executors.newScheduledThreadPool(1); |
| this.watermarkTriggerService.scheduleAtFixedRate(() -> |
| watermarkTriggered = true, |
| WATERMARK_PERIOD, WATERMARK_PERIOD, TimeUnit.MILLISECONDS); |
| } else { |
| this.watermarkTriggerService = null; |
| } |
| } |
| |
| /** |
| * This is non-blocking operation. |
| * |
| * @return current data |
| */ |
| @Override |
| Object fetchDataElement() { |
| if (readable.isFinished()) { |
| return Finishmark.getInstance(); |
| } else { |
| final long start = System.currentTimeMillis(); |
| final Object element = retrieveElement(); |
| boundedSourceReadTime += System.currentTimeMillis() - start; |
| return element; |
| } |
| } |
| |
| final long getBoundedSourceReadTime() { |
| return boundedSourceReadTime; |
| } |
| |
| @Override |
| public void close() throws Exception { |
| readable.close(); |
| if (watermarkTriggerService != null) { |
| watermarkTriggerService.shutdown(); |
| } |
| } |
| |
| private boolean isWatermarkTriggerTime() { |
| if (watermarkTriggered) { |
| watermarkTriggered = false; |
| return true; |
| } else { |
| return false; |
| } |
| } |
| |
| private Object retrieveElement() { |
| // Emit watermark |
| if (!bounded && isWatermarkTriggerTime()) { |
| return new Watermark(readable.readWatermark()); |
| } |
| |
| // Data |
| return readable.readCurrent(); |
| } |
| } |