/*
 * Symphony - A modern community (forum/SNS/blog) platform written in Java.
 * Copyright (C) 2012-2017,  b3log.org & hacpai.com
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU 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 General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */
package org.b3log.symphony.util;

import org.apache.commons.lang.StringUtils;

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

/**
 * Network utilities.
 *
 * @author <a href="http://88250.b3log.org">Liang Ding</a>
 * @version 1.0.2.0, Mar 2, 2017
 * @since 1.3.0
 */
public final class Networks {

    /**
     * Is IPv4.
     *
     * @param ip ip
     * @return {@code true} if it is, returns {@code false} otherwise
     */
    public static boolean isIPv4(final String ip) {
        if (StringUtils.isBlank(ip)) {
            return false;
        }

        final String regex = "^(([01]?\\d\\d?|2[0-4]\\d|25[0-5])\\.){3}([01]?\\d\\d?|2[0-4]\\d|25[0-5])$";

        final Pattern pattern = Pattern.compile(regex);
        final Matcher matcher = pattern.matcher(ip);

        return matcher.matches();
    }

    /**
     * Private constructor.
     */
    private Networks() {
    }
}
