it.polito.tellmefirst.web.rest.utils.LangDetectUtils.java Source code

Introduction

Here is the source code for it.polito.tellmefirst.web.rest.utils.LangDetectUtils.java

Source

/**
 * TellMeFirst - A Knowledge Discovery Application
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU Affero General Public License as
 * published by the Free Software Foundation, either version 3 of the
 * License, or (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU Affero General Public License for more details.
 *
 * You should have received a copy of the GNU Affero General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */

package it.polito.tellmefirst.web.rest.utils;

import java.io.InputStream;
import java.net.JarURLConnection;
import java.net.URL;
import java.util.ArrayList;
import java.util.Enumeration;
import java.util.HashMap;
import java.util.List;
import java.util.jar.JarEntry;
import java.util.jar.JarFile;

import org.apache.commons.io.IOUtils;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;

import com.cybozu.labs.langdetect.Detector;
import com.cybozu.labs.langdetect.DetectorFactory;
import com.cybozu.labs.langdetect.LangDetectException;
import com.cybozu.labs.langdetect.Language;

/**
 * Created by User:
 */
public class LangDetectUtils {

    static Log LOG = LogFactory.getLog(LangDetectUtils.class);

    private static LangDetectUtils langDetectUtils;

    public static final String defaultLang = "english";
    public static final HashMap<String, String> mapLangCode = new HashMap<String, String>();
    static {
        mapLangCode.put("en", "english");
        mapLangCode.put("it", "italian");
        // ... TODO if other languages will be supported
    }

    /** A private Constructor prevents any other class from instantiating. */
    private LangDetectUtils() {
        try {

            String dirname = "profiles/";
            Enumeration<URL> en = Detector.class.getClassLoader().getResources(dirname);
            List<String> profiles = new ArrayList<String>();
            if (en.hasMoreElements()) {
                URL url = en.nextElement();
                JarURLConnection urlcon = (JarURLConnection) url.openConnection();
                JarFile jar = urlcon.getJarFile();
                Enumeration<JarEntry> entries = jar.entries();
                while (entries.hasMoreElements()) {
                    String entry = entries.nextElement().getName();
                    if (entry.startsWith(dirname)) {
                        InputStream in = Detector.class.getClassLoader().getResourceAsStream(entry);
                        profiles.add(IOUtils.toString(in));
                    }
                }

            }
            DetectorFactory.loadProfile(profiles);
        } catch (LangDetectException e) {
            LOG.error("Error loading profiles directory " + e.getMessage());
        } catch (Exception e) {
            LOG.error("Error loading profiles directory " + e.getMessage());
        }
    }

    public static synchronized LangDetectUtils getLangDetectUtils() {
        if (langDetectUtils == null) {
            langDetectUtils = new LangDetectUtils();
        }
        return langDetectUtils;
    }

    public String detect(String text) throws LangDetectException {

        String langCode = null;
        String mappedLang = null;

        Detector detector = DetectorFactory.create();
        detector.append(text);

        langCode = detector.detect();
        LOG.debug("langCode=" + langCode);

        mappedLang = mapLangCode.get(langCode);
        if (mappedLang == null)
            mappedLang = defaultLang;
        LOG.debug("mappedLang=" + langCode);

        return mappedLang;
    }

    public ArrayList<Language> detectLangs(String text) throws LangDetectException {
        Detector detector = DetectorFactory.create();
        detector.append(text);
        return detector.getProbabilities();
    }

    public Object clone() throws CloneNotSupportedException {
        throw new CloneNotSupportedException();
    }

}