org.apache.ignite.internal.processors.hadoop.v1.GridHadoopV1ReduceTask.java Source code

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/*
 * 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 org.apache.ignite.internal.processors.hadoop.v1;

import org.apache.hadoop.mapred.*;
import org.apache.hadoop.util.*;
import org.apache.ignite.*;
import org.apache.ignite.internal.processors.hadoop.*;
import org.apache.ignite.internal.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 IgniteCheckedException {
        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 IgniteCheckedException(e);
        }
    }
}