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/*
 * Copyright (c) 2008-2019, 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;

import com.hazelcast.nio.serialization.BinaryInterface;

import java.io.Serializable;

/**
 * 
 * A CombinerFactory implementation is used to build {@link Combiner} instances per key.

 * An implementation needs to be serializable by Hazelcast since it is distributed together with
 * the {@link Mapper} implementation to run alongside.
 * 
 *
 * @param     key type of the resulting keys
 * @param   value type of the incoming values
 * @param  value type of the reduced values
 * @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 * For general data processing, it is superseded by Hazelcast Jet.
 */
@Deprecated
@BinaryInterface
public interface CombinerFactory
        extends Serializable {

    /**
     * Build a new {@link Combiner} instance specific to the supplied key.
     *
     * @param key key that the new Combiner is build for
     * @return a Combiner instance specific for the given key
     */
    Combiner newCombiner(KeyIn key);

}