/*
* Cloud9: A MapReduce Library for Hadoop
*
* 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.collection.wikipedia.graph;
import java.io.IOException;
import java.util.Iterator;
import java.util.Random;
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.conf.Configured;
import org.apache.hadoop.fs.FileSystem;
import org.apache.hadoop.fs.Path;
import org.apache.hadoop.io.IntWritable;
import org.apache.hadoop.io.Text;
import org.apache.hadoop.mapred.JobClient;
import org.apache.hadoop.mapred.JobConf;
import org.apache.hadoop.mapred.MapFileOutputFormat;
import org.apache.hadoop.mapred.MapReduceBase;
import org.apache.hadoop.mapred.Mapper;
import org.apache.hadoop.mapred.OutputCollector;
import org.apache.hadoop.mapred.Partitioner;
import org.apache.hadoop.mapred.Reducer;
import org.apache.hadoop.mapred.Reporter;
import org.apache.hadoop.mapred.SequenceFileInputFormat;
import org.apache.hadoop.mapred.SequenceFileOutputFormat;
import org.apache.hadoop.mapred.TextInputFormat;
import org.apache.hadoop.mapred.TextOutputFormat;
import org.apache.hadoop.util.Tool;
import org.apache.hadoop.util.ToolRunner;
import org.apache.log4j.Logger;
import edu.umd.cloud9.collection.wikipedia.WikipediaPage;
import edu.umd.cloud9.collection.wikipedia.WikipediaPage.Link;
import edu.umd.cloud9.io.map.HMapSIW;
import edu.umd.cloud9.io.pair.PairOfIntString;
import edu.umd.cloud9.io.pair.PairOfStringInt;
import edu.umd.cloud9.io.pair.PairOfStrings;
/**
* Tool for extracting anchor text out of Wikipedia.
*
* @author Jimmy Lin
*/
public class ExtractWikipediaAnchorText extends Configured implements Tool {
private static final Logger LOG = Logger.getLogger(ExtractWikipediaAnchorText.class);
private static enum PageTypes {
TOTAL, REDIRECT, DISAMBIGUATION, EMPTY, ARTICLE, STUB, NON_ARTICLE
};
private static class MyMapper1 extends MapReduceBase implements
Mapper<IntWritable, WikipediaPage, PairOfStringInt, PairOfStrings> {
private static final PairOfStringInt KEYPAIR = new PairOfStringInt();
private static final PairOfStrings VALUEPAIR = new PairOfStrings();
// Basic algorithm:
// Emit: key = (link target article name, 0), value = (link target docid, "");
// Emit: key = (link target article name, 1), value = (src docid, anchor text)
public void map(IntWritable key, WikipediaPage p,
OutputCollector<PairOfStringInt, PairOfStrings> output, Reporter reporter)
throws IOException {
reporter.incrCounter(PageTypes.TOTAL, 1);
String title = p.getTitle();
// This is a caveat and a potential gotcha: Wikipedia article titles are not case sensitive on
// the initial character, so a link to "commodity" will go to the article titled "Commodity"
// without any issue. Therefore we need to emit two versions of article titles.
VALUEPAIR.set(p.getDocid(), "");
KEYPAIR.set(title, 0);
output.collect(KEYPAIR, VALUEPAIR);
String fc = title.substring(0, 1);
if (fc.matches("[A-Z]")) {
title = title.replaceFirst(fc, fc.toLowerCase());
KEYPAIR.set(title, 0);
output.collect(KEYPAIR, VALUEPAIR);
}
if (p.isRedirect()) {
reporter.incrCounter(PageTypes.REDIRECT, 1);
} else if (p.isDisambiguation()) {
reporter.incrCounter(PageTypes.DISAMBIGUATION, 1);
} else if (p.isEmpty()) {
reporter.incrCounter(PageTypes.EMPTY, 1);
} else if (p.isArticle()) {
reporter.incrCounter(PageTypes.ARTICLE, 1);
if (p.isStub()) {
reporter.incrCounter(PageTypes.STUB, 1);
}
} else {
reporter.incrCounter(PageTypes.NON_ARTICLE, 1);
}
for (Link link : p.extractLinks()) {
KEYPAIR.set(link.getTarget(), 1);
VALUEPAIR.set(p.getDocid(), link.getAnchorText());
output.collect(KEYPAIR, VALUEPAIR);
}
}
}
private static class MyReducer1 extends MapReduceBase implements
Reducer<PairOfStringInt, PairOfStrings, IntWritable, PairOfIntString> {
private static final IntWritable SRCID = new IntWritable();
private static final PairOfIntString TARGET_ANCHOR_PAIR = new PairOfIntString();
private String targetTitle;
private int targetDocid;
public void reduce(PairOfStringInt key, Iterator<PairOfStrings> values,
OutputCollector<IntWritable, PairOfIntString> output, Reporter reporter) throws IOException {
if (key.getRightElement() == 0) {
targetTitle = key.getLeftElement();
targetDocid = Integer.parseInt(values.next().getLeftElement());
} else {
if (!key.getLeftElement().equals(targetTitle)) {
return;
}
while (values.hasNext()) {
PairOfStrings pair = values.next();
SRCID.set(Integer.parseInt(pair.getLeftElement()));
TARGET_ANCHOR_PAIR.set(targetDocid, pair.getRightElement());
output.collect(SRCID, TARGET_ANCHOR_PAIR);
}
}
}
}
private static class MyPartitioner1 implements Partitioner<PairOfStringInt, PairOfStrings> {
public void configure(JobConf job) {}
public int getPartition(PairOfStringInt key, PairOfStrings value, int numReduceTasks) {
return (key.getLeftElement().hashCode() & Integer.MAX_VALUE) % numReduceTasks;
}
}
private static class MyMapper2 extends MapReduceBase implements
Mapper<IntWritable, PairOfIntString, IntWritable, Text> {
private static final IntWritable KEY = new IntWritable();
private static final Text VALUE = new Text();
public void map(IntWritable key, PairOfIntString t, OutputCollector<IntWritable, Text> output,
Reporter reporter) throws IOException {
KEY.set(t.getLeftElement());
VALUE.set(t.getRightElement());
output.collect(KEY, VALUE);
}
}
private static class MyReducer2 extends MapReduceBase implements
Reducer<IntWritable, Text, IntWritable, HMapSIW> {
private static final HMapSIW map = new HMapSIW();
public void reduce(IntWritable key, Iterator<Text> values,
OutputCollector<IntWritable, HMapSIW> output, Reporter reporter) throws IOException {
map.clear();
Text cur;
while (values.hasNext()) {
cur = values.next();
map.increment(cur.toString());
}
output.collect(key, map);
}
}
private static final String INPUT_OPTION = "input";
private static final String OUTPUT_OPTION = "output";
@SuppressWarnings("static-access")
@Override
public int run(String[] args) throws Exception {
Options options = new Options();
options.addOption(OptionBuilder.withArgName("path").hasArg()
.withDescription("input").create(INPUT_OPTION));
options.addOption(OptionBuilder.withArgName("path").hasArg()
.withDescription("output for adjacency list").create(OUTPUT_OPTION));
CommandLine cmdline;
CommandLineParser parser = new GnuParser();
try {
cmdline = parser.parse(options, args);
} catch (ParseException exp) {
System.err.println("Error parsing command line: " + exp.getMessage());
return -1;
}
if (!cmdline.hasOption(INPUT_OPTION) || !cmdline.hasOption(OUTPUT_OPTION)) {
HelpFormatter formatter = new HelpFormatter();
formatter.printHelp(this.getClass().getName(), options);
ToolRunner.printGenericCommandUsage(System.out);
return -1;
}
Random random = new Random();
String tmp = "tmp-" + this.getClass().getCanonicalName() + "-" + random.nextInt(10000);
task1(cmdline.getOptionValue(INPUT_OPTION), tmp);
task2(tmp, cmdline.getOptionValue(OUTPUT_OPTION));
return 0;
}
private void task1(String inputPath, String outputPath) throws IOException {
LOG.info("Exracting anchor text (phase 1)...");
LOG.info(" - input: " + inputPath);
LOG.info(" - output: " + outputPath);
JobConf conf = new JobConf(getConf(), ExtractWikipediaAnchorText.class);
conf.setJobName(String.format(
"ExtractWikipediaAnchorText:phase1[input: %s, output: %s]", inputPath, outputPath));
// 10 reducers is reasonable.
conf.setNumReduceTasks(10);
SequenceFileInputFormat.addInputPath(conf, new Path(inputPath));
TextOutputFormat.setOutputPath(conf, new Path(outputPath));
conf.setInputFormat(SequenceFileInputFormat.class);
conf.setOutputFormat(SequenceFileOutputFormat.class);
conf.setMapOutputKeyClass(PairOfStringInt.class);
conf.setMapOutputValueClass(PairOfStrings.class);
conf.setOutputKeyClass(IntWritable.class);
conf.setOutputValueClass(PairOfIntString.class);
conf.setMapperClass(MyMapper1.class);
conf.setReducerClass(MyReducer1.class);
conf.setPartitionerClass(MyPartitioner1.class);
// Delete the output directory if it exists already.
FileSystem.get(conf).delete(new Path(outputPath), true);
JobClient.runJob(conf);
}
private void task2(String inputPath, String outputPath) throws IOException {
LOG.info("Exracting anchor text (phase 2)...");
LOG.info(" - input: " + inputPath);
LOG.info(" - output: " + outputPath);
JobConf conf = new JobConf(getConf(), ExtractWikipediaAnchorText.class);
conf.setJobName(String.format(
"ExtractWikipediaAnchorText:phase2[input: %s, output: %s]", inputPath, outputPath));
// Gathers everything together for convenience; feasible for Wikipedia.
conf.setNumReduceTasks(1);
TextInputFormat.addInputPath(conf, new Path(inputPath));
TextOutputFormat.setOutputPath(conf, new Path(outputPath));
conf.setInputFormat(SequenceFileInputFormat.class);
conf.setOutputFormat(MapFileOutputFormat.class);
conf.setMapOutputKeyClass(IntWritable.class);
conf.setMapOutputValueClass(Text.class);
conf.setOutputKeyClass(IntWritable.class);
conf.setOutputValueClass(HMapSIW.class);
conf.setMapperClass(MyMapper2.class);
conf.setReducerClass(MyReducer2.class);
// Delete the output directory if it exists already.
FileSystem.get(conf).delete(new Path(outputPath), true);
JobClient.runJob(conf);
// Clean up intermediate data.
FileSystem.get(conf).delete(new Path(inputPath), true);
}
public ExtractWikipediaAnchorText() {}
public static void main(String[] args) throws Exception {
int res = ToolRunner.run(new ExtractWikipediaAnchorText(), args);
System.exit(res);
}
}