D-Net

/*

 * This file is part of CoAnSys project.

 * Copyright (c) 2012-2015 ICM-UW

 * 

 * CoAnSys 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.

 * CoAnSys 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 CoAnSys. If not, see <http://www.gnu.org/licenses/>.

 */

package eu.dnetlib.dhp.common.string;

import java.text.Normalizer;

import java.util.HashMap;

import java.util.Map;

/**

 * Mapping to the basic Latin alphabet (a-z, A-Z). In most cases, a character is

 * mapped to the closest visual form, rather than functional one, e.g.: "ö" is

 * mapped to "o" rather than "oe", and "đ" is mapped to "d" rather than "dj" or

 * "gj". Notable exceptions include: "ĸ" mapped to "q", "ß" mapped to "ss", and

 * "Þ", "þ" mapped to "Y", "y".

 *

 * <p> Each character is processed as follows: <ol> <li>the character is

 * compatibility decomposed,</li> <li>all the combining marks are removed,</li>

 * <li>the character is compatibility composed,</li> <li>additional "manual"

 * substitutions are applied.</li> </ol> </p>

 *

 * <p> All the characters from the "Latin-1 Supplement" and "Latin Extended-A"

 * Unicode blocks are mapped to the "Basic Latin" block. Characters from other

 * alphabets are generally left intact, although the decomposable ones may be

 * affected by the procedure. </p>

 *

 * @author Lukasz Bolikowski (bolo@icm.edu.pl)

 * 

 * @author Łukasz Dumiszewski /just copied from coansys-commons/

 *

 */

public final class DiacriticsRemover {

    private static final Character[] from = {

        'Æ', 'Ð', 'Ø', 'Þ', 'ß', 'æ', 'ð', 'ø', 'þ', 'Đ', 'đ', 'Ħ',

        'ħ', 'ı', 'ĸ', 'Ł', 'ł', 'Ŋ', 'ŋ', 'Œ', 'œ', 'Ŧ', 'ŧ'};

    private static final String[] to = {

        "AE", "D", "O", "Y", "ss", "ae", "d", "o", "y", "D", "d", "H",

        "h", "i", "q", "L", "l", "N", "n", "OE", "oe", "T", "t"};

    private static Map<Character, String> lookup = buildLookup();

    //------------------------ CONSTRUCTORS -------------------

    private DiacriticsRemover() {}

    //------------------------ LOGIC --------------------------

    /**

     * Removes diacritics from a text.

     *

     * @param text Text to process.

     * @return Text without diacritics.

     */

    public static String removeDiacritics(String text) {

        if (text == null) {

            return null;

        }

        String tmp = Normalizer.normalize(text, Normalizer.Form.NFKD);

        StringBuilder builder = new StringBuilder();

        for (int i = 0; i < tmp.length(); i++) {

            Character ch = tmp.charAt(i);

            if (Character.getType(ch) == Character.NON_SPACING_MARK) {

                continue;

            }

            if (lookup.containsKey(ch)) {

                builder.append(lookup.get(ch));

            } else {

                builder.append(ch);

            }

        }

        return builder.toString();

    }

    //------------------------ PRIVATE --------------------------

    private static Map<Character, String> buildLookup() {

        if (from.length != to.length) {

            throw new IllegalStateException();

        }

        Map<Character, String> _lookup = new HashMap<Character, String>();

        for (int i = 0; i < from.length; i++) {

            _lookup.put(from[i], to[i]);

        }

        return _lookup;

    }

}