de.malkusch.whoisServerList.publicSuffixList.util.DomainUtil Maven / Gradle / Ivy

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Public Suffix List API

There is a newer version: 2.2.0

package de.malkusch.whoisServerList.publicSuffixList.util;

import java.util.Collection;

import javax.annotation.concurrent.ThreadSafe;

import org.apache.commons.lang3.StringUtils;

/**
 * Domain utility class.
 *
 * @author [email protected]
 * @see Donations
 */
@ThreadSafe
public final class DomainUtil {

    /**
     * Private utility class constructor.
     */
    private DomainUtil() {
    }

    /**
     * Splits a domain or pattern into its labels.
     *
     * Splitting is done at ".".
     *
     * @param domain  the domain name or rule pattern, null returns null
     * @return the domain or rule label, or null
     */
    public static String[] splitLabels(final String domain) {
        if (domain == null) {
            return null;

        }
        if (domain.isEmpty()) {
            return new String[]{};

        }
        return domain.split("\\.");
    }

    /**
     * Joins labels to a domain name or rule pattern.
     *
     * Joining is done with ".".
     *
     * @param labels  the domain or rule labels, not null
     * @return the domain name or rule pattern
     */
    public static String joinLabels(final Collection labels) {
        return joinLabels(labels.toArray(new String[]{}));
    }

    /**
     * Joins labels to a domain name or rule pattern.
     *
     * Joining is done with ".".
     *
     * @param labels  the domain or rule labels, not null
     * @return the domain name or rule pattern
     */
    public static String joinLabels(final String[] labels) {
        return StringUtils.join(labels, '.');
    }

}