ZDB.java

/*
 * Copyright (C) 2014 Jörg Prante
 *
 * 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
 * or write to the Free Software Foundation, Inc., 51 Franklin Street,
 * Fifth Floor, Boston, MA 02110-1301 USA.
 *
 * The interactive user interfaces in modified source and object code
 * versions of this program must display Appropriate Legal Notices,
 * as required under Section 5 of the GNU Affero General Public License.
 *
 */
package org.xbib.standardnumber;

import java.util.regex.Matcher;
import java.util.regex.Pattern;

/**
 * Zeitschriftendatenbank ID
 *
 *  ZDB is the world’s largest specialized database for serial titles (journals, annuals, newspapers, also
 *  e-journals).
 *
 * @see <a href="http://support.d-nb.de/iltis/onlineRoutinen/Pruefziffernberechnung.htm"></a>Prüfziffernberechnung in ILTIS</a>
 * @see <a href="https://wiki.dnb.de/pages/viewpage.action?pageId=48139522">DNB Wiki</a>
 */
public class ZDB extends AbstractStandardNumber implements Comparable<ZDB>, StandardNumber {

    private final static Pattern PATTERN = Pattern.compile("^[\\p{Digit}]{2,10}\\-{0,1}[\\p{Digit}xX]{1}\\b");

    private String value;

    private String formatted;

    private boolean createWithChecksum;

    @Override
    public String type() {
        return "zdb";
    }

    @Override
    public ZDB set(CharSequence value) {
        this.value = value != null ? value.toString() : null;
        return this;
    }

    @Override
    public int compareTo(ZDB o) {
        return value != null ?  value.compareTo(o.normalizedValue()) : -1;
    }

    @Override
    public String normalizedValue() {
        return value;
    }

    @Override
    public ZDB createChecksum(boolean createWithChecksum) {
        this.createWithChecksum = createWithChecksum;
        return this;
    }

    @Override
    public ZDB normalize() {
        Matcher m = PATTERN.matcher(value);
        if (m.find()) {
            this.value = dehyphenate(value.substring(m.start(), m.end()));
        }
        return this;
    }

    @Override
    public boolean isValid() {
        return value != null && !value.isEmpty() && check();
    }

    @Override
    public ZDB verify() throws NumberFormatException {
        if (value == null || value.isEmpty()) {
            throw new NumberFormatException("invalid");
        }
        if (!check()) {
            throw new NumberFormatException("bad checksum");
        }
        return this;
    }

    @Override
    public String format() {
        if (formatted == null) {
            StringBuilder sb = new StringBuilder(value);
            this.formatted = sb.insert(sb.length()-1,"-").toString();
        }
        return formatted;
    }

    @Override
    public ZDB reset() {
        this.value = null;
        this.formatted = null;
        this.createWithChecksum = false;
        return this;
    }

    private boolean check() {
        int l = value.length() - 1;
        int checksum = 0;
        int weight = 2;
        int val;
        for (int i = l-1; i >= 0; i--) {
            val = value.charAt(i) - '0';
            checksum += val * weight++;
        }
        if (createWithChecksum) {
            char ch = checksum % 11 == 10 ? 'X' : (char)('0' + (checksum % 11));
            value = value.substring(0, l) + ch;
        }
        return checksum % 11 ==
                (value.charAt(l) == 'X' || value.charAt(l) == 'x' ? 10 : value.charAt(l) - '0');
    }

    private String dehyphenate(String value) {
        StringBuilder sb = new StringBuilder(value);
        int i = sb.indexOf("-");
        while (i >= 0) {
            sb.deleteCharAt(i);
            i = sb.indexOf("-");
        }
        return sb.toString();
    }
}