de.hpi.fgis.hdrs.mapreduce.examples.PredicateCount.java Source code

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Here is the source code for de.hpi.fgis.hdrs.mapreduce.examples.PredicateCount.java

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/**
 * Copyright 2011 Daniel Hefenbrock
 *
 * 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 de.hpi.fgis.hdrs.mapreduce.examples;

import java.io.IOException;

import org.apache.hadoop.conf.Configured;
import org.apache.hadoop.fs.Path;
import org.apache.hadoop.io.BytesWritable;
import org.apache.hadoop.io.IntWritable;
import org.apache.hadoop.io.NullWritable;
import org.apache.hadoop.mapreduce.Job;
import org.apache.hadoop.mapreduce.Mapper;
import org.apache.hadoop.mapreduce.Reducer;
import org.apache.hadoop.mapreduce.lib.output.FileOutputFormat;
import org.apache.hadoop.mapreduce.lib.output.SequenceFileOutputFormat;
import org.apache.hadoop.util.Tool;
import org.apache.hadoop.util.ToolRunner;

import de.hpi.fgis.hdrs.Triple;
import de.hpi.fgis.hdrs.mapreduce.TripleInputFormat;

public class PredicateCount extends Configured implements Tool {

    public static class Map extends Mapper<NullWritable, Triple, BytesWritable, IntWritable> {

        private final static IntWritable one = new IntWritable(1);
        private BytesWritable pred = new BytesWritable();

        public void map(NullWritable key, Triple value, Context context) throws IOException, InterruptedException {
            pred.set(value.getBuffer(), value.getPredicateOffset(), value.getPredicateLength());
            context.write(pred, one);
        }
    }

    public static class Reduce extends Reducer<BytesWritable, IntWritable, BytesWritable, IntWritable> {

        public void reduce(BytesWritable key, Iterable<IntWritable> values, Context context)
                throws IOException, InterruptedException {
            int sum = 0;
            for (IntWritable val : values) {
                sum += val.get();
            }
            context.write(key, new IntWritable(sum));
        }
    }

    @Override
    public int run(String[] args) throws Exception {
        Job job = new Job(getConf());
        job.setJarByClass(PredicateCount.class);
        job.setJobName("PredicateCount");

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

        job.setMapperClass(Map.class);
        job.setCombinerClass(Reduce.class);
        job.setReducerClass(Reduce.class);

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

        int argc = 0;

        TripleInputFormat.setStoreAddress(job, args[argc++]);
        TripleInputFormat.setIndex(job, args[argc++]);
        if ("-p".equals(args[argc])) {
            argc++;
            String s = args[argc++];
            String p = args[argc++];
            String o = args[argc++];
            if ("*".equals(s))
                s = null;
            if ("*".equals(p))
                p = null;
            if ("*".equals(o))
                o = null;
            TripleInputFormat.setPattern(job, Triple.newPattern(s, p, o));
        } else {
            FileOutputFormat.setOutputPath(job, new Path(args[argc]));
        }

        boolean success = job.waitForCompletion(true);
        return success ? 0 : 1;
    }

    public static void main(String[] args) throws Exception {
        int ret = ToolRunner.run(new PredicateCount(), args);
        System.exit(ret);
    }

}