package org.archive.hadoop.mapreduce;
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.net.URI;
import java.net.URISyntaxException;
import java.nio.charset.Charset;
import java.util.ArrayList;
import java.util.Arrays;
import org.apache.hadoop.conf.Configurable;
import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.fs.FSDataInputStream;
import org.apache.hadoop.fs.FileSystem;
import org.apache.hadoop.fs.Path;
import org.apache.hadoop.io.Text;
import org.apache.hadoop.mapreduce.Partitioner;
public class AlphaPartitioner extends Partitioner<Text, Text> implements
Configurable {
// TODO: refactor
private static final Charset UTF8 = Charset.forName("UTF-8");
private static String CONFIG_SPLIT_PATH_NAME = "alphapartitioner.path";
private String boundaries[] = new String[0];
Configuration conf;
@Override
public int getPartition(Text key, Text value, int numPartitions) {
String keyS = key.toString();
int loc = Arrays.binarySearch(boundaries, keyS);
if (loc < 0) {
loc = (loc * -1) - 2;
if (loc < 0) {
loc = 0;
}
}
return loc;
}
public Configuration getConf() {
return conf;
}
public void setConf(Configuration conf) {
this.conf = conf;
String partitionPath = getPartitionPath(conf);
String numReduceTasks = conf.get("mapred.reduce.tasks");
System.err.println("AlphaPartitioner-reducers: " + numReduceTasks);
System.err.println("AlphaPartitioner-partitionPath: " + partitionPath);
try {
URI uri = new URI(partitionPath);
FileSystem fs = FileSystem.get(uri, conf);
Path p = new Path(partitionPath);
loadBoundaries(new BufferedReader(new InputStreamReader(fs.open(p))));
} catch (IOException e) {
// TODO: ugh. how to handle?
e.printStackTrace();
} catch (URISyntaxException e) {
e.printStackTrace();
}
}
/**
* @param conf
* Configuration for the Job
* @param path
* hdfs:// URI pointing to the split file
*/
public static void setPartitionPath(Configuration conf, String path) {
conf.set(CONFIG_SPLIT_PATH_NAME, path);
}
/**
* @param conf
* Configuration for the Job
* @return the hdfs:// URI for the split file configured for this job
*/
public static String getPartitionPath(Configuration conf) {
return conf.get(CONFIG_SPLIT_PATH_NAME);
}
public static int countLinesInPath(Path path, Configuration conf)
throws IOException {
FileSystem fs = path.getFileSystem(conf);
FSDataInputStream is = fs.open(path);
BufferedReader br = new BufferedReader(new InputStreamReader(is, UTF8));
int lineCount = 0;
while (br.readLine() != null) {
lineCount++;
}
is.close();
return lineCount;
}
private void loadBoundaries(BufferedReader bis) throws IOException {
ArrayList<String> l = new ArrayList<String>();
while (true) {
String line = bis.readLine();
if (line == null) {
break;
}
l.add(line);
}
boundaries = l.toArray(boundaries);
Arrays.sort(boundaries);
}
}