| // 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; |
| |
| /** |
| * An event is a wrapper object that gets stored in the window. |
| * |
| * @param <T> the type of the object thats wrapped. E.g Tuple |
| */ |
| public interface Event<T> { |
| /** |
| * The event timestamp in millis. This could be the time |
| * when the source generated the tuple or the time |
| * when the tuple was received by a bolt. |
| * |
| * @return the event timestamp in milliseconds. |
| */ |
| long getTimestamp(); |
| |
| /** |
| * Returns the wrapped object, E.g. a tuple |
| * |
| * @return the wrapped object. |
| */ |
| T get(); |
| |
| /** |
| * If this is a watermark event or not. Watermark events are used |
| * for tracking time while processing event based ts. |
| * |
| * @return true if this is a watermark event |
| */ |
| boolean isWatermark(); |
| } |