com.twitter.heron.api.windowing.Window Maven / Gradle / Ivy
// 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.
/**
* 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 com.twitter.heron.api.windowing;
import java.util.List;
/**
* A view of events in a sliding window.
*
* @param the type of event that this window contains. E.g. {@link org.apache.storm.tuple.Tuple}
*/
public interface Window {
/**
* Gets the list of events in the window.
*
* Note: If the number of tuples in windows is huge, invoking {@code get} would
* load all the tuples into memory and may throw an OOM exception. Use windowing with persistence
*
*
* @return the list of events in the window.
*/
List get();
/**
* Get the list of newly added events in the window since the last time the window was generated.
*
* @return the list of newly added events in the window.
*/
List getNew();
/**
* Get the list of events expired from the window since the last time the window was generated.
*
* @return the list of events expired from the window.
*/
List getExpired();
/**
* If processing based on event time, returns the window end time based on watermark otherwise
* returns the window end time based on processing time.
*
* @return the window end timestamp
*/
Long getEndTimestamp();
/**
* Returns the window start timestamp. Will return null if the window length is not based on
* time duration.
*
* @return the window start timestamp or null if the window length is not time based
*/
Long getStartTimestamp();
}