/**
* Program: HBaseRecordPro.java
* Editor: Waue Chen
* From : NCHC. Taiwn
* Last Update Date: 07/02/2008
* Upgrade to 0.17
*/
/*
* Cloud9: A MapReduce Library for Hadoop
*/
package tw.org.nchc.demo;
import java.io.IOException;
import java.util.Iterator;
import java.util.StringTokenizer;
import org.apache.hadoop.fs.FileSystem;
import org.apache.hadoop.fs.Path;
import org.apache.hadoop.io.IntWritable;
import org.apache.hadoop.io.LongWritable;
import org.apache.hadoop.io.Text;
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.Reducer;
import org.apache.hadoop.mapred.Reporter;
import tw.org.nchc.code.Convert;
/**
*
Simple word count demo. Counts words in the Bible+Shakespeare sample
* collection. Expected trace of MapReduce operation:
*
*
* Map input records=156215
* Map output records=1734298
* Map input bytes=9068074
* Map output bytes=15919397
* Combine input records=1734298
* Combine output records=135372
* Reduce input groups=41788
* Reduce input records=135372
* Reduce output records=41788
*
*
*/
public class DemoWordCount {
// mapper: emits (token, 1) for every word occurrence
private static class MapClass extends MapReduceBase implements
Mapper {
// reuse objects to save overhead of object creation
private final static IntWritable one = new IntWritable(1);
private Text word = new Text();
public void map(LongWritable key, Text value,
OutputCollector output, Reporter reporter)
throws IOException {
String line = ((Text) value).toString();
StringTokenizer itr = new StringTokenizer(line);
while (itr.hasMoreTokens()) {
word.set(itr.nextToken());
output.collect(word, one);
}
}
}
// reducer: sums up all the counts
private static class ReduceClass extends MapReduceBase implements
Reducer {
// reuse objects
private final static IntWritable SumValue = new IntWritable();
public void reduce(Text key, Iterator values,
OutputCollector output, Reporter reporter)
throws IOException {
// sum up values
int sum = 0;
while (values.hasNext()) {
sum += values.next().get();
}
SumValue.set(sum);
output.collect(key, SumValue);
}
}
private DemoWordCount() {
}
/**
* Runs the demo.
*/
public static void main(String[] args) throws IOException {
String filename = "/user/waue/test/132.txt";
String outputPath = "sample-counts";
int mapTasks = 20;
int reduceTasks = 1;
JobConf conf = new JobConf(DemoWordCount.class);
conf.setJobName("wordcount");
conf.setNumMapTasks(mapTasks);
conf.setNumReduceTasks(reduceTasks);
//0.16
// conf.setInputPath(new Path(filename));
Convert.setInputPath(conf, new Path(filename));
conf.setOutputKeyClass(Text.class);
conf.setOutputValueClass(IntWritable.class);
// 0.16
// conf.setOutputPath(new Path(outputPath));
Convert.setInputPath(conf, new Path(outputPath));
conf.setMapperClass(MapClass.class);
conf.setCombinerClass(ReduceClass.class);
conf.setReducerClass(ReduceClass.class);
// Delete the output directory if it exists already
Path outputDir = new Path(outputPath);
// 0.16
// FileSystem.get(conf).delete(outputDir);
FileSystem.get(conf).delete(outputDir,true);
JobClient.runJob(conf);
}
}