org.kiji.mapreduce.output.HFileReducerMapReduceJobOutput.java Source code

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Here is the source code for org.kiji.mapreduce.output.HFileReducerMapReduceJobOutput.java

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/**
 * (c) Copyright 2013 WibiData, Inc.
 *
 * See the NOTICE file distributed with this work for additional
 * information regarding copyright ownership.
 *
 * 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.kiji.mapreduce.output;

import java.io.IOException;

import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.mapreduce.Job;
import org.apache.hadoop.mapreduce.OutputFormat;
import org.apache.hadoop.mapreduce.lib.output.FileOutputFormat;
import org.apache.hadoop.mapreduce.lib.output.SequenceFileOutputFormat;

import org.kiji.mapreduce.KijiConfKeys;
import org.kiji.mapreduce.KijiTableContext;
import org.kiji.mapreduce.MapReduceJobOutput;
import org.kiji.mapreduce.context.HFileWriterContext;

/**
 * M/R job output configuration for a job intending to reduce into HFiles.
 *
 * Used for the special case when the user wants a reducer to write HFiles.
 * Reducers can't write HFiles directly, but must write SequenceFiles that will be post-processed
 * (sorted) by an identity Map/Reduce in order to finally write HFiles.
 */
public class HFileReducerMapReduceJobOutput extends MapReduceJobOutput {
    private final HFileMapReduceJobOutput mJobOutput;

    /**
     * Initializes an instance.
     *
     * @param jobOutput Wraps this HFile M/R job output.
     */
    public HFileReducerMapReduceJobOutput(HFileMapReduceJobOutput jobOutput) {
        mJobOutput = jobOutput;
    }

    /** {@inheritDoc} */
    @Override
    public void configure(Job job) throws IOException {
        super.configure(job); // sets the Hadoop output format

        final Configuration conf = job.getConfiguration();
        conf.set(KijiConfKeys.KIJI_OUTPUT_TABLE_URI, mJobOutput.getTable().getURI().toString());

        // Kiji table context:
        conf.setClass(KijiConfKeys.KIJI_TABLE_CONTEXT_CLASS, HFileWriterContext.class, KijiTableContext.class);

        // Set the output path.
        FileOutputFormat.setOutputPath(job, mJobOutput.getPath());

        job.setNumReduceTasks(mJobOutput.getNumReduceTasks());
    }

    /** {@inheritDoc} */
    @Override
    protected Class<? extends OutputFormat> getOutputFormatClass() {
        return SequenceFileOutputFormat.class;
    }
}