/**
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you 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.
 */
// This code has been copied from hadoop-common 0.23.1
package org.apache.bookkeeper.net;

import java.net.InetAddress;
import java.net.UnknownHostException;
import java.util.ArrayList;
import java.util.Collection;
import java.util.List;

public class NetUtils {

    /**
     * Given a string representation of a host, return its ip address
     * in textual presentation.
     *
     * @param name a string representation of a host:
     *             either a textual representation its IP address or its host name
     * @return its IP address in the string format
     */
    public static String normalizeHostName(String name) {
        try {
            return InetAddress.getByName(name).getHostAddress();
        } catch (UnknownHostException e) {
            return name;
        }
    }

    /**
     * Given a collection of string representation of hosts, return a list of
     * corresponding IP addresses in the textual representation.
     *
     * @param names a collection of string representations of hosts
     * @return a list of corresponding IP addresses in the string format
     * @see #normalizeHostName(String)
     */
    public static List<String> normalizeHostNames(Collection<String> names) {
        List<String> hostNames = new ArrayList<String>(names.size());
        for (String name : names) {
            hostNames.add(normalizeHostName(name));
        }
        return hostNames;
    }

}
