com.epam.deltix.util.io.CachedLocalIP Maven / Gradle / Ivy

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/*
 * Copyright 2021 EPAM Systems, Inc
 *
 * See the NOTICE file distributed with this work for additional information
 * regarding copyright ownership. 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.
 */
package com.epam.deltix.util.io;

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

/**
 * Caches local IP address.
 * Attention: Doesn't track dynamic IP address changes.      
 */
public abstract class CachedLocalIP {
    private static String localIP = null;

    public static String getIP() {
        if (localIP == null) {
            try {
                final InetAddress addr = InetAddress.getLocalHost();
                final StringBuilder s = new StringBuilder();
                for (byte b : addr.getAddress()) {
                    s.append(String.format("%02x", b & 0xFF));
                }
                localIP = s.toString();
            } catch (UnknownHostException x) {
                throw new com.epam.deltix.util.io.UncheckedIOException(x);
            }
        }
        return localIP;
    }
}