/*
* Copyright (c) 2008-2017, Hazelcast, Inc. 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.hazelcast.mapreduce;
/**
* This interface can be implemented to define a Collator which is executed after calculation
* of the MapReduce algorithm on remote cluster nodes but before returning the final result.<br>
* Collator can, for example, be used to sum up a final value.
*
* @param <ValueIn> value type of the resulting values
* @param <ValueOut> type for the collated result
* @since 3.2
* @deprecated MapReduce is deprecated and will be removed in 4.0.
* For map aggregations, you can use {@link com.hazelcast.aggregation.Aggregator} on IMap.
* For general data processing, it is superseded by <a href="http://jet.hazelcast.org">Hazelcast Jet</a>.
*/
@Deprecated
public interface Collator<ValueIn, ValueOut> {
/**
* This method is called with the mapped and possibly reduced values from the MapReduce algorithm.
*
* @param values The mapped and possibly reduced values from the MapReduce algorithm
* @return The collated result
*/
ValueOut collate(Iterable<ValueIn> values);
}