org.openimaj.hadoop.tools.downloader.HadoopDownloader Maven / Gradle / Ivy

Go to download
Show more of this group Show more artifacts with this name
Show all versions of HadoopDownloader Show documentation
Distributed download tool.
The newest version!
/**
 * Copyright (c) 2011, The University of Southampton and the individual contributors.
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without modification,
 * are permitted provided that the following conditions are met:
 *
 *   * 	Redistributions of source code must retain the above copyright notice,
 * 	this list of conditions and the following disclaimer.
 *
 *   *	Redistributions in binary form must reproduce the above copyright notice,
 * 	this list of conditions and the following disclaimer in the documentation
 * 	and/or other materials provided with the distribution.
 *
 *   *	Neither the name of the University of Southampton nor the names of its
 * 	contributors may be used to endorse or promote products derived from this
 * 	software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
 * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR
 * ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON
 * ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */
package org.openimaj.hadoop.tools.downloader;

import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.conf.Configured;
import org.apache.hadoop.io.BytesWritable;
import org.apache.hadoop.io.SequenceFile.CompressionType;
import org.apache.hadoop.io.Text;
import org.apache.hadoop.io.compress.DefaultCodec;
import org.apache.hadoop.mapreduce.Job;
import org.apache.hadoop.mapreduce.lib.input.FileInputFormat;
import org.apache.hadoop.mapreduce.lib.input.TextInputFormat;
import org.apache.hadoop.mapreduce.lib.map.MultithreadedMapper;
import org.apache.hadoop.mapreduce.lib.output.SequenceFileOutputFormat;
import org.apache.hadoop.util.Tool;
import org.apache.hadoop.util.ToolRunner;

/**
 * A tool for the distributed downloading of data into Hadoop SequenceFiles.
 * 
 * @author Sina Samangooei ([email protected])
 * @author Jonathon Hare ([email protected])
 * 
 */
public class HadoopDownloader extends Configured implements Tool {
	protected static final String ARGS_KEY = "hadoop.downloader.args";

	@Override
	public int run(String[] args) throws Exception {
		final HadoopDownloaderOptions options = new HadoopDownloaderOptions(args);
		options.prepare(true);

		final Job job = new Job(getConf());

		job.setJarByClass(HadoopDownloader.class);
		job.setJobName("Hadoop Downloader Utility");

		job.setOutputKeyClass(Text.class);
		job.setOutputValueClass(BytesWritable.class);

		if (options.getNumberOfThreads() <= 1) {
			job.setMapperClass(DownloadMapper.class);
		} else {
			job.setMapperClass(MultithreadedMapper.class);
			MultithreadedMapper.setMapperClass(job, DownloadMapper.class);
			MultithreadedMapper.setNumberOfThreads(job, options.getNumberOfThreads());
		}

		job.setInputFormatClass(TextInputFormat.class);
		job.setOutputFormatClass(SequenceFileOutputFormat.class);

		job.setNumReduceTasks(options.getNumberOfReducers());

		job.getConfiguration().setStrings(ARGS_KEY, args);

		FileInputFormat.setInputPaths(job, options.getInputPaths());
		SequenceFileOutputFormat.setOutputPath(job, options.getOutputPath());
		SequenceFileOutputFormat.setCompressOutput(job, true);
		SequenceFileOutputFormat.setOutputCompressorClass(job, DefaultCodec.class);
		SequenceFileOutputFormat.setOutputCompressionType(job, CompressionType.BLOCK);

		job.waitForCompletion(true);

		return 0;
	}

	/**
	 * Main program entry point
	 * 
	 * @param args
	 *            command-line arguments
	 * @throws Exception
	 *             if an error occurs
	 */
	public static void main(String[] args) throws Exception {
		final int res = ToolRunner.run(new Configuration(), new HadoopDownloader(), args);

		System.exit(res);
	}
}