| /** |
| * 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.apex.malhar.lib.window.impl; |
| |
| import javax.annotation.Nonnegative; |
| |
| import org.apache.apex.malhar.lib.window.ControlTuple; |
| import org.apache.apex.malhar.lib.window.ImplicitWatermarkGenerator; |
| import org.apache.apex.malhar.lib.window.Tuple; |
| import org.apache.hadoop.classification.InterfaceStability; |
| |
| import com.datatorrent.api.Context; |
| |
| /** |
| * An @{@link ImplicitWatermarkGenerator} implementation for generating watermarks |
| * based on event time. |
| * |
| * Generates a watermark tuple with a fixed difference from the latest event time. |
| * |
| * @since 3.7.0 |
| */ |
| @InterfaceStability.Evolving |
| public class FixedDiffEventTimeWatermarkGen implements ImplicitWatermarkGenerator |
| { |
| @Nonnegative |
| private long fixedDifference; |
| private long maxEventTime = -1; |
| |
| public FixedDiffEventTimeWatermarkGen(long fixedDifference) |
| { |
| this.fixedDifference = fixedDifference; |
| } |
| |
| /** |
| * {@inheritDoc} |
| */ |
| @Override |
| public void processTupleForWatermark(Tuple.WindowedTuple t, long currentProcessingTime) |
| { |
| long eventTime = t.getTimestamp(); |
| if (maxEventTime < eventTime) { |
| maxEventTime = eventTime; |
| } |
| } |
| |
| /** |
| * {@inheritDoc} |
| */ |
| @Override |
| public ControlTuple.Watermark getWatermarkTuple(long currentProcessingTime) |
| { |
| return new WatermarkImpl(maxEventTime - fixedDifference); |
| } |
| |
| @Override |
| public void setup(Context context) |
| { |
| } |
| |
| @Override |
| public void teardown() |
| { |
| } |
| |
| public void setFixedDifference(long fixedDifference) |
| { |
| this.fixedDifference = fixedDifference; |
| } |
| } |