heron/api/src/java/com/twitter/heron/api/windowing/WaterMarkEvent.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.windowing;

/**
 * Watermark event used for tracking progress of time when
 * processing event based ts.
 */
public class WaterMarkEvent<T> extends EventImpl<T> {
  public WaterMarkEvent(long ts) {
    super(null, ts);
  }

  @Override
  public boolean isWatermark() {
    return true;
  }

  @Override
  public String toString() {
    return "WaterMarkEvent{} " + super.toString();
  }
}