de.siegmar.logbackgelf.InetUtil Maven / Gradle / Ivy

/*
 * Logback GELF - zero dependencies Logback GELF appender library.
 * Copyright (C) 2019 Oliver Siegmar
 *
 * 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.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
 */

package de.siegmar.logbackgelf;

import java.net.InetAddress;
import java.net.UnknownHostException;

final class InetUtil {

    private InetUtil() {
    }

    /**
     * Retrieves the local host's name. Preferably the fully qualified one.
     *
     * @return the (fully qualified) name of local host or the IP address if not resolvable.
     * @throws UnknownHostException if the hostname could not be resolved due to a system
     *                              misconfiguration.
     */
    static String getLocalHostName() throws UnknownHostException {
        final InetAddress localHost = InetAddress.getLocalHost();
        final String canonicalHostName = localHost.getCanonicalHostName();
        return canonicalHostName.isEmpty() ? localHost.getHostName() : canonicalHostName;
    }

}