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

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Here is the source code for de.hpi.fgis.hdrs.mapreduce.examples.PredicateAnalysis.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.LongWritable;
import org.apache.hadoop.io.NullWritable;
import org.apache.hadoop.io.Text;
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.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 PredicateAnalysis extends Configured implements Tool {

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

        private Triple current = null;
        private long count = 0;

        public void map(NullWritable key, Triple value, Context context) throws IOException, InterruptedException {

            if (null == current) {
                current = value;
            }

            if (Triple.buffersEqual(current.getBuffer(), current.getObjectOffset(), current.getObjectLength(),
                    value.getBuffer(), value.getObjectOffset(), value.getObjectLength())) {
                count += value.getMultiplicity();
            } else {
                BytesWritable object = new BytesWritable();
                object.set(current.getBuffer(), current.getObjectOffset(), current.getObjectLength());
                context.write(object, new LongWritable(count));

                current = value;
                count = 1;
            }
        }
    }

    public static class Reduce extends Reducer<BytesWritable, LongWritable, Text, Text> {

        public void reduce(BytesWritable key, Iterable<LongWritable> values, Context context)
                throws IOException, InterruptedException {
            context.write(new Text(new String(key.getBytes(), 0, key.getLength())),
                    new Text("" + values.iterator().next()));
        }
    }

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

        job.setMapOutputKeyClass(BytesWritable.class);
        job.setMapOutputValueClass(LongWritable.class);

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

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

        job.setNumReduceTasks(0);

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

        TripleInputFormat.setStoreAddress(job, args[0]);
        TripleInputFormat.setIndex(job, "POS");
        TripleInputFormat.setPattern(job, Triple.newPattern(null, args[1], null));
        TripleInputFormat.setAggregationLevel2(job);

        SequenceFileOutputFormat.setOutputPath(job, new Path(args[2]));

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

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

}