de.l3s.content.mapred.WikipediaPagesBz2InputStream.java Source code

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Here is the source code for de.l3s.content.mapred.WikipediaPagesBz2InputStream.java

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/*
 * 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 de.l3s.content.mapred;

import java.io.BufferedReader;
import java.io.FileInputStream;
import java.io.IOException;
import java.io.InputStreamReader;

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.util.ToolRunner;
import org.apache.tools.bzip2.CBZip2InputStream;

import edu.umd.cloud9.collection.wikipedia.WikipediaPage;
import edu.umd.cloud9.collection.wikipedia.language.WikipediaPageFactory;

/**
 * Class for working with bz2-compressed Wikipedia article dump files on local disk.
 *
 * @author Jimmy Lin
 * @author Peter Exner
 */
public class WikipediaPagesBz2InputStream {
    private static int DEFAULT_STRINGBUFFER_CAPACITY = 1024;

    private BufferedReader br;
    private FileInputStream fis;

    /**
     * Creates an input stream for reading Wikipedia articles from a bz2-compressed dump file.
     *
     * @param file path to dump file
     * @throws IOException
     */
    public WikipediaPagesBz2InputStream(String file) throws IOException {
        br = null;
        fis = new FileInputStream(file);
        byte[] ignoreBytes = new byte[2];
        fis.read(ignoreBytes); // "B", "Z" bytes from commandline tools
        br = new BufferedReader(new InputStreamReader(new CBZip2InputStream(fis)));

    }

    /**
     * Reads the next Wikipedia page.
     *
     * @param page WikipediaPage object to read into
     * @return <code>true</code> if page is successfully read
     * @throws IOException
     */
    public boolean readNext(WikipediaPage page) throws IOException {
        String s = null;
        StringBuffer sb = new StringBuffer(DEFAULT_STRINGBUFFER_CAPACITY);

        while ((s = br.readLine()) != null) {
            if (s.endsWith("<page>"))
                break;
        }

        if (s == null) {
            fis.close();
            br.close();
            return false;
        }

        sb.append(s + "\n");

        while ((s = br.readLine()) != null) {
            sb.append(s + "\n");

            if (s.endsWith("</page>"))
                break;
        }

        WikipediaPage.readPage(page, sb.toString());

        return true;
    }

    private static final String INPUT_OPTION = "input";
    private static final String LANGUAGE_OPTION = "output";

    @SuppressWarnings("static-access")
    public static void main(String[] args) throws Exception {
        Options options = new Options();
        options.addOption(OptionBuilder.withArgName("path").hasArg().withDescription("gzipped XML dump file")
                .create(INPUT_OPTION));
        options.addOption(OptionBuilder.withArgName("lang").hasArg().withDescription("output location")
                .create(LANGUAGE_OPTION));

        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_OPTION)) {
            HelpFormatter formatter = new HelpFormatter();
            formatter.printHelp(WikipediaPagesBz2InputStream.class.getCanonicalName(), options);
            ToolRunner.printGenericCommandUsage(System.out);
            System.exit(-1);
        }

        String path = cmdline.getOptionValue(INPUT_OPTION);
        String lang = cmdline.hasOption(LANGUAGE_OPTION) ? cmdline.getOptionValue(LANGUAGE_OPTION) : "en";
        WikipediaPage p = WikipediaPageFactory.createWikipediaPage(lang);

        WikipediaPagesBz2InputStream stream = new WikipediaPagesBz2InputStream(path);
        while (stream.readNext(p)) {
            System.out.println(p.getTitle() + "\t" + p.getDocid());
        }
    }
}