Java Socket Address Get getAddressFirst(InetSocketAddress inetSocketAddress)

Description

Returns the String form of the IP address of the given InetSocketAddress , or the hostname if it has not been resolved.

License

Apache License

Parameter

Parameter	Description
inetSocketAddress	the socket address in which to retrieve the address from

Return

the String representation of the address or the hostname, or null if neither can be found.

Declaration

public static String getAddressFirst(InetSocketAddress inetSocketAddress)

Method Source Code

//package com.java2s;
/*/*from  w  w w  .  java2  s.c o m*/
 * Copyright 2018 NAVER Corp.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

import java.net.InetAddress;
import java.net.InetSocketAddress;

public class Main {
    /**
     * Returns the String form of the IP address of the given {@link InetSocketAddress}, or the hostname
     * if it has not been resolved. Returns {@code null} if neither can be retrieved.
     *
     * <p>This <b>does not</b> trigger a DNS lookup if the address has not been resolved yet by simply
     * returning the hostname.
     *
     * @param inetSocketAddress the socket address in which to retrieve the address from
     * @return  the String representation of the address or the hostname, or {@code null} if neither
     *          can be found.
     *
     * @see InetSocketAddress#isUnresolved()
     */
    public static String getAddressFirst(InetSocketAddress inetSocketAddress) {
        if (inetSocketAddress == null) {
            return null;
        }
        InetAddress inetAddress = inetSocketAddress.getAddress();
        if (inetAddress != null) {
            return inetAddress.getHostAddress();
        }
        // This won't trigger a DNS lookup as if it got to here, the hostName should not be null on the basis
        // that InetSocketAddress does not allow both address and hostName fields to be null.
        return inetSocketAddress.getHostName();
    }

    /**
     * Returns the String form of the IP address of the given {@link InetSocketAddress}, or the hostname
     * if it has not been resolved. Returns {@code defaultAddress} if neither can be retrieved.
     *
     * <p>This <b>does not</b> trigger a DNS lookup if the address has not been resolved yet by simply
     * returning the hostname.
     *
     * @param inetSocketAddress the socket address in which to retrieve the address from
     * @param defaultAddress    the value to return if neither the string form of the address nor the
     *                          hostname can be found
     * @return  the String representation of the address or the hostname, or {@code defaultAddress} if neither
     *          can be found.
     *
     * @see InetSocketAddress#isUnresolved()
     */
    public static String getAddressFirst(InetSocketAddress inetSocketAddress, String defaultAddress) {
        String address = getAddressFirst(inetSocketAddress);
        if (address == null) {
            return defaultAddress;
        }
        return address;
    }
}