/*
* Cloud9: A Hadoop toolkit for working with big data
*
* 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 edu.umd.cloud9.example.bigram;
import java.util.Arrays;
import java.util.Collections;
import java.util.Comparator;
import java.util.Iterator;
import java.util.List;
import org.apache.commons.cli.CommandLine;
import org.apache.commons.cli.CommandLineParser;
import org.apache.commons.cli.GnuParser;
import org.apache.commons.cli.HelpFormatter;
import org.apache.commons.cli.OptionBuilder;
import org.apache.commons.cli.Options;
import org.apache.commons.cli.ParseException;
import org.apache.hadoop.fs.Path;
import org.apache.hadoop.io.IntWritable;
import org.apache.hadoop.io.Text;
import org.apache.hadoop.util.ToolRunner;
import tl.lin.data.pair.PairOfWritables;
import com.google.common.collect.Iterators;
import edu.umd.cloud9.io.SequenceFileUtils;
public class AnalyzeBigramCount {
private static final String INPUT = "input";
@SuppressWarnings({ "static-access" })
public static void main(String[] args) {
Options options = new Options();
options.addOption(OptionBuilder.withArgName("path").hasArg()
.withDescription("input path").create(INPUT));
CommandLine cmdline = null;
CommandLineParser parser = new GnuParser();
try {
cmdline = parser.parse(options, args);
} catch (ParseException exp) {
System.err.println("Error parsing command line: " + exp.getMessage());
System.exit(-1);
}
if (!cmdline.hasOption(INPUT)) {
System.out.println("args: " + Arrays.toString(args));
HelpFormatter formatter = new HelpFormatter();
formatter.setWidth(120);
formatter.printHelp(AnalyzeBigramCount.class.getName(), options);
ToolRunner.printGenericCommandUsage(System.out);
System.exit(-1);
}
String inputPath = cmdline.getOptionValue(INPUT);
System.out.println("input path: " + inputPath);
List<PairOfWritables<Text, IntWritable>> bigrams =
SequenceFileUtils.readDirectory(new Path(inputPath));
Collections.sort(bigrams, new Comparator<PairOfWritables<Text, IntWritable>>() {
public int compare(PairOfWritables<Text, IntWritable> e1,
PairOfWritables<Text, IntWritable> e2) {
if (e2.getRightElement().compareTo(e1.getRightElement()) == 0) {
return e1.getLeftElement().compareTo(e2.getLeftElement());
}
return e2.getRightElement().compareTo(e1.getRightElement());
}
});
int singletons = 0;
int sum = 0;
for (PairOfWritables<Text, IntWritable> bigram : bigrams) {
sum += bigram.getRightElement().get();
if (bigram.getRightElement().get() == 1) {
singletons++;
}
}
System.out.println("total number of unique bigrams: " + bigrams.size());
System.out.println("total number of bigrams: " + sum);
System.out.println("number of bigrams that appear only once: " + singletons);
System.out.println("\nten most frequent bigrams: ");
Iterator<PairOfWritables<Text, IntWritable>> iter = Iterators.limit(bigrams.iterator(), 10);
while (iter.hasNext()) {
PairOfWritables<Text, IntWritable> bigram = iter.next();
System.out.println(bigram.getLeftElement() + "\t" + bigram.getRightElement());
}
}
}