/*
 * 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.
 */
package org.apache.geode.test.dunit;

import org.apache.geode.distributed.internal.DistributionConfig;
import org.apache.geode.internal.net.SocketCreator;

import java.net.UnknownHostException;

/**
 * <code>NetworkUtils</code> provides static utility methods to perform network DNS lookups or
 * similar actions.
 * 
 * These methods can be used directly: <code>NetworkUtils.getIPLiteral()</code>, however, they are
 * intended to be referenced through static import:
 *
 * <pre>
 * import static org.apache.geode.test.dunit.NetworkUtils.*;
 *    ...
 *    String hostName = getIPLiteral();
 * </pre>
 *
 * Extracted from DistributedTestCase.
 */
public class NetworkUtils {

  protected NetworkUtils() {}

  /**
   * Get the IP literal name for the current host. Use this instead of "localhost" to avoid IPv6
   * name resolution bugs in the JDK/machine config. This method honors java.net.preferIPvAddresses
   * 
   * @return an IP literal which honors java.net.preferIPvAddresses
   */
  public static String getIPLiteral() {
    try {
      return SocketCreator.getLocalHost().getHostAddress();
    } catch (UnknownHostException e) {
      throw new Error("Problem determining host IP address", e);
    }
  }

  /**
   * Get the host name to use for a server cache in client/server dunit testing.
   * 
   * @param host the dunit Host to get a machine host name for
   * @return the host name
   */
  public static String getServerHostName(final Host host) {
    String serverBindAddress =
        System.getProperty(DistributionConfig.GEMFIRE_PREFIX + "server-bind-address");
    return serverBindAddress != null ? serverBindAddress : host.getHostName();
  }
}