org.apache.flink.runtime.taskexecutor.GlobalAggregateManager Maven / Gradle / Ivy
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* Licensed to the Apache Software Foundation (ASF) under one
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* distributed with this work for additional information
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* 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,
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*/
package org.apache.flink.runtime.taskexecutor;
import java.io.IOException;
import org.apache.flink.api.common.functions.AggregateFunction;
/**
* This interface gives access to transient, named, global aggregates. This can be sued to share
* state amongst parallel tasks in a job. It is not designed for high throughput updates
* and the aggregates do NOT survive a job failure. Each call to the updateGlobalAggregate()
* method results in serialized RPC communication with the JobMaster so use with care.
*/
public interface GlobalAggregateManager {
/**
* Update the global aggregate and return the new value.
*
* @param aggregateName The name of the aggregate to update
* @param aggregand The value to add to the aggregate
* @param aggregateFunction The function to apply to the current aggregate and aggregand to
* obtain the new aggregate value
* @return The updated aggregate
*/
OUT updateGlobalAggregate(String aggregateName, Object aggregand, AggregateFunction aggregateFunction) throws IOException;
}