heron/api/src/java/com/twitter/heron/api/bolt/IWindowedBolt.java

//  Copyright 2017 Twitter. All rights reserved.
//
//  Licensed 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 com.twitter.heron.api.bolt;

import java.util.Map;

import com.twitter.heron.api.topology.IComponent;
import com.twitter.heron.api.topology.TopologyContext;
import com.twitter.heron.api.windowing.TimestampExtractor;
import com.twitter.heron.api.windowing.TupleWindow;

/**
 * A bolt abstraction for supporting time and count based sliding & tumbling windows.
 */
public interface IWindowedBolt extends IComponent {
  /**
   * This is similar to the
   * {@link com.twitter.heron.api.bolt.IBolt#prepare(Map, TopologyContext, OutputCollector)}
   * except
   * that while emitting, the tuples are automatically anchored to the tuples in the inputWindow.
   */
  void prepare(Map<String, Object> topoConf, TopologyContext context, OutputCollector collector);

  /**
   * Process the tuple window and optionally emit new tuples based on the tuples in the input
   * window.
   */
  void execute(TupleWindow inputWindow);

  void cleanup();

  /**
   * Return a {@link TimestampExtractor} for extracting timestamps from a
   * tuple for event time based processing, or null for processing time.
   *
   * @return the timestamp extractor
   */
  TimestampExtractor getTimestampExtractor();
}