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43025
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eri.katsar
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package eu.dnetlib.data.mapreduce.hbase.lodExport.build;
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42692
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eri.katsar
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43143
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giorgos.al
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import java.io.IOException;
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43395
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eri.katsar
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import java.nio.charset.Charset;
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43143
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giorgos.al
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import java.util.Iterator;
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42692
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eri.katsar
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import org.apache.hadoop.io.Text;
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import org.apache.hadoop.mapreduce.Reducer;
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43395
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eri.katsar
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import org.apache.hadoop.mapreduce.TaskInputOutputContext;
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import org.apache.hadoop.mapreduce.lib.output.MultipleOutputs;
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42692
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eri.katsar
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import org.apache.log4j.Logger;
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43025
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eri.katsar
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public class BlockReducer extends Reducer<Text, Text, Text, Text> {
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43950
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eri.katsar
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private static final String SEPERATOR = ",";
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43897
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eri.katsar
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43485
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eri.katsar
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public static enum BLOCKS_COUNTER {
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TOTAL_ENTITIES
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43093
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eri.katsar
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}
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42692
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eri.katsar
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43093
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eri.katsar
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private Logger log = Logger.getLogger(BlockReducer.class);
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42692
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eri.katsar
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43395
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eri.katsar
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private MultipleOutputs MultipleOutputWriter;
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43025
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eri.katsar
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43395
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eri.katsar
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43093
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eri.katsar
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@Override
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protected void setup(Context context) throws IOException, InterruptedException {
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43395
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eri.katsar
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MultipleOutputWriter = new MultipleOutputs((TaskInputOutputContext) context);
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43093
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eri.katsar
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}
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42692
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eri.katsar
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43093
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eri.katsar
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@Override
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protected void reduce(final Text key, final Iterable<Text> values, final Context context) throws IOException, InterruptedException {
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Iterator<Text> it = values.iterator();
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43054
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eri.katsar
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43093
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eri.katsar
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try {
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//each list is a block
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StringBuilder field = new StringBuilder();
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43395
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eri.katsar
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int nunberOfEntities = 0;
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43093
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eri.katsar
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while (it.hasNext()) {
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eri.katsar
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field.append(it.next()).append(SEPERATOR);
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43395
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eri.katsar
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nunberOfEntities++;
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}
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43100
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eri.katsar
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43897
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eri.katsar
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MultipleOutputWriter.write("b", key, new Text(field.toString()), "blocks/b");
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43485
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eri.katsar
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MultipleOutputWriter.write("entitiesNumber", key, new Text(String.valueOf(nunberOfEntities).getBytes(Charset.forName("UTF-8"))), "stats/entitiesNumber");
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context.getCounter(BLOCKS_COUNTER.TOTAL_ENTITIES).increment(1);
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43093
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eri.katsar
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} catch (Exception e) {
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throw new InterruptedException(e.getMessage());
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}
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42692
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eri.katsar
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43093
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eri.katsar
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}
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42802
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eri.katsar
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43093
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eri.katsar
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@Override
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protected void cleanup(Context context) throws IOException, InterruptedException {
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log.info("Cleaning up reducer...");
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eri.katsar
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MultipleOutputWriter.close();
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43093
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eri.katsar
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}
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42692
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eri.katsar
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}
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