/**
* 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.alibaba.jstorm.window;
import backtype.storm.tuple.Tuple;
import java.io.Serializable;
import java.util.Collection;
/**
* A retractor enables re-computing of purged historic windows.
* Note that for such re-computing, user would need to pull window states from their own state factory,
* e.g., HBase, HDFS, DB, etc. instead of state factory within JStorm.
*
* @author wange
* @since 16/12/19
*/
public interface Retractor extends Serializable {
void retract(Tuple element, Collection<TimeWindow> windows);
}