org.gridgain.grid.kernal.processors.hadoop.v1.GridHadoopV1ReduceTask.java Source code

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Here is the source code for org.gridgain.grid.kernal.processors.hadoop.v1.GridHadoopV1ReduceTask.java

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/* 
 Copyright (C) GridGain Systems. 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 org.gridgain.grid.kernal.processors.hadoop.v1;

import org.apache.hadoop.mapred.*;
import org.apache.hadoop.util.*;
import org.gridgain.grid.*;
import org.gridgain.grid.hadoop.*;
import org.gridgain.grid.kernal.processors.hadoop.*;
import org.gridgain.grid.kernal.processors.hadoop.v2.*;

/**
 * Hadoop reduce task implementation for v1 API.
 */
public class GridHadoopV1ReduceTask extends GridHadoopV1Task {
    /** {@code True} if reduce, {@code false} if combine. */
    private final boolean reduce;

    /**
     * Constructor.
     *
     * @param taskInfo Task info.
     * @param reduce {@code True} if reduce, {@code false} if combine.
     */
    public GridHadoopV1ReduceTask(GridHadoopTaskInfo taskInfo, boolean reduce) {
        super(taskInfo);

        this.reduce = reduce;
    }

    /** {@inheritDoc} */
    @SuppressWarnings("unchecked")
    @Override
    public void run(GridHadoopTaskContext taskCtx) throws GridException {
        GridHadoopJob job = taskCtx.job();

        GridHadoopV2TaskContext ctx = (GridHadoopV2TaskContext) taskCtx;

        JobConf jobConf = ctx.jobConf();

        GridHadoopTaskInput input = taskCtx.input();

        GridHadoopV1OutputCollector collector = null;

        try {
            collector = collector(jobConf, ctx, reduce || !job.info().hasReducer(), fileName(), ctx.attemptId());

            Reducer reducer = ReflectionUtils
                    .newInstance(reduce ? jobConf.getReducerClass() : jobConf.getCombinerClass(), jobConf);

            assert reducer != null;

            try {
                try {
                    while (input.next()) {
                        if (isCancelled())
                            throw new GridHadoopTaskCancelledException("Reduce task cancelled.");

                        reducer.reduce(input.key(), input.values(), collector, Reporter.NULL);
                    }
                } finally {
                    reducer.close();
                }
            } finally {
                collector.closeWriter();
            }

            collector.commit();
        } catch (Exception e) {
            if (collector != null)
                collector.abort();

            throw new GridException(e);
        }
    }
}