com.liferay.portal.kernel.util.NaturalOrderStringComparator.java Source code

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Here is the source code for com.liferay.portal.kernel.util.NaturalOrderStringComparator.java

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/**
 * Copyright (c) 2000-present Liferay, Inc. All rights reserved.
 *
 * This library is free software; you can redistribute it and/or modify it under
 * the terms of the GNU Lesser General Public License as published by the Free
 * Software Foundation; either version 2.1 of the License, or (at your option)
 * any later version.
 *
 * This library 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 Lesser General Public License for more
 * details.
 */

package com.liferay.portal.kernel.util;

import com.liferay.petra.string.StringPool;

import java.io.Serializable;

import java.util.Comparator;

/**
 * @author Hugo Huijser
 */
public class NaturalOrderStringComparator implements Comparator<String>, Serializable {

    public NaturalOrderStringComparator() {
        this(true, false);
    }

    public NaturalOrderStringComparator(boolean ascending, boolean caseSensitive) {

        _ascending = ascending;
        _caseSensitive = caseSensitive;
    }

    @Override
    public int compare(String s1, String s2) {
        if (s1 == null) {
            s1 = StringPool.BLANK;
        }

        if (s2 == null) {
            s2 = StringPool.BLANK;
        }

        int value = 0;

        int i1 = 0;
        int i2 = 0;

        int length1 = s1.length();
        int length2 = s2.length();

        while ((i1 < length1) && (i2 < length2)) {
            char c1 = s1.charAt(i1);
            char c2 = s2.charAt(i2);

            if (Validator.isDigit(c1) && Validator.isDigit(c2)) {
                String leadingDigitsAsString1 = StringUtil.extractLeadingDigits(s1.substring(i1));
                String leadingDigitsAsString2 = StringUtil.extractLeadingDigits(s2.substring(i2));

                int leadingNumber1 = GetterUtil.getInteger(leadingDigitsAsString1);
                int leadingNumber2 = GetterUtil.getInteger(leadingDigitsAsString2);

                if (leadingNumber1 != leadingNumber2) {
                    value = leadingNumber1 - leadingNumber2;

                    break;
                }

                i1 += leadingDigitsAsString1.length();
                i2 += leadingDigitsAsString2.length();

                continue;
            }

            if (isCheckSpecialCharacters() && Validator.isAscii(c1) && Validator.isAscii(c2)) {

                boolean digitOrLetter1 = _isDigitOrLetter(c1);
                boolean digitOrLetter2 = _isDigitOrLetter(c2);

                if (digitOrLetter1 ^ digitOrLetter2) {
                    if (digitOrLetter1) {
                        value = 1;
                    } else {
                        value = -1;
                    }

                    break;
                }
            }

            if (c1 == c2) {
                i1++;
                i2++;

                continue;
            }

            if (_caseSensitive) {
                value = c1 - c2;

                break;
            }

            char c1UpperCase = Character.toUpperCase(c1);
            char c2UpperCase = Character.toUpperCase(c2);

            if (c1UpperCase == c2UpperCase) {
                i1++;
                i2++;

                continue;
            }

            value = c1UpperCase - c2UpperCase;

            break;
        }

        if ((value == 0) && (length1 != length2)) {
            if ((length1 == i1) && (length2 == i2)) {
                value = length2 - length1;
            } else {
                value = length1 - length2;
            }
        }

        if (_ascending) {
            return value;
        }

        return -value;
    }

    protected boolean isCheckSpecialCharacters() {
        return true;
    }

    private boolean _isDigitOrLetter(char c) {
        if (Validator.isChar(c) || Validator.isDigit(c)) {
            return true;
        }

        return false;
    }

    private final boolean _ascending;
    private final boolean _caseSensitive;

}