edu.umd.cloud9.collection.line.DemoCountTextDocuments.java Source code

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Here is the source code for edu.umd.cloud9.collection.line.DemoCountTextDocuments.java

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/*
 * Cloud9: A MapReduce Library for Hadoop
 *
 * 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 edu.umd.cloud9.collection.line;

import java.io.IOException;

import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.conf.Configured;
import org.apache.hadoop.fs.Path;
import org.apache.hadoop.io.LongWritable;
import org.apache.hadoop.io.NullWritable;
import org.apache.hadoop.mapred.FileInputFormat;
import org.apache.hadoop.mapred.JobClient;
import org.apache.hadoop.mapred.JobConf;
import org.apache.hadoop.mapred.MapReduceBase;
import org.apache.hadoop.mapred.Mapper;
import org.apache.hadoop.mapred.OutputCollector;
import org.apache.hadoop.mapred.Reporter;
import org.apache.hadoop.mapred.lib.NullOutputFormat;
import org.apache.hadoop.util.Tool;
import org.apache.hadoop.util.ToolRunner;
import org.apache.log4j.Logger;

public class DemoCountTextDocuments extends Configured implements Tool {

    private static final Logger sLogger = Logger.getLogger(DemoCountTextDocuments.class);

    private static enum Count {
        DOCS
    };

    private static class MyMapper extends MapReduceBase
            implements Mapper<LongWritable, TextDocument, NullWritable, NullWritable> {

        public void configure(JobConf job) {
        }

        public void map(LongWritable key, TextDocument doc, OutputCollector<NullWritable, NullWritable> output,
                Reporter reporter) throws IOException {
            reporter.incrCounter(Count.DOCS, 1);
        }
    }

    /**
     * Creates an instance of this tool.
     */
    public DemoCountTextDocuments() {
    }

    private static int printUsage() {
        System.out.println("usage: [input]");
        ToolRunner.printGenericCommandUsage(System.out);
        return -1;
    }

    /**
     * Runs this tool.
     */
    public int run(String[] args) throws Exception {
        if (args.length != 1) {
            printUsage();
            return -1;
        }

        String inputPath = args[0];

        sLogger.info("input: " + inputPath);

        JobConf conf = new JobConf(DemoCountTextDocuments.class);
        conf.setJobName("DemoCountTextDocuments");

        conf.setNumReduceTasks(0);

        FileInputFormat.setInputPaths(conf, new Path(inputPath));

        conf.setInputFormat(TextDocumentInputFormat.class);
        conf.setOutputFormat(NullOutputFormat.class);
        conf.setMapperClass(MyMapper.class);

        JobClient.runJob(conf);

        return 0;
    }

    /**
     * Dispatches command-line arguments to the tool via the
     * <code>ToolRunner</code>.
     */
    public static void main(String[] args) throws Exception {
        int res = ToolRunner.run(new Configuration(), new DemoCountTextDocuments(), args);
        System.exit(res);
    }
}