content: package com.lxr.iot.util;
  
  /*
   * 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.
   */
  
  import org.slf4j.Logger;
  import org.slf4j.LoggerFactory;
  
  import java.io.IOException;
  import java.lang.reflect.Method;
  import java.net.*;
  import java.nio.channels.Selector;
  import java.nio.channels.SocketChannel;
  import java.nio.channels.spi.SelectorProvider;
  import java.util.ArrayList;
  import java.util.Enumeration;
  
  public class RemotingUtil {
      public static final String OS_NAME = System.getProperty("os.name");
  
      private static final Logger log = LoggerFactory.getLogger(RemotingUtil.class);
      private static boolean isLinuxPlatform = false;
      private static boolean isWindowsPlatform = false;
  
      static {
          if (OS_NAME != null && OS_NAME.toLowerCase().contains("linux")) {
              isLinuxPlatform = true;
          }
  
          if (OS_NAME != null && OS_NAME.toLowerCase().contains("windows")) {
              isWindowsPlatform = true;
          }
      }
  
      public static boolean isWindowsPlatform() {
          return isWindowsPlatform;
      }
  
      public static Selector openSelector() throws IOException {
          Selector result = null;
  
          if (isLinuxPlatform()) {
              try {
                  final Class<?> providerClazz = Class.forName("sun.nio.ch.EPollSelectorProvider");
                  if (providerClazz != null) {
                      try {
                          final Method method = providerClazz.getMethod("provider");
                          if (method != null) {
                              final SelectorProvider selectorProvider = (SelectorProvider) method.invoke(null);
                              if (selectorProvider != null) {
                                  result = selectorProvider.openSelector();
                              }
                          }
                      } catch (final Exception e) {
                          log.warn("Open ePoll Selector for linux platform exception", e);
                      }
                  }
              } catch (final Exception e) {
                  // ignore
              }
          }
  
          if (result == null) {
              result = Selector.open();
          }
  
          return result;
      }
  
      public static boolean isLinuxPlatform() {
          return isLinuxPlatform;
      }
  
      public static String getLocalAddress() {
          try {
              // Traversal Network interface to get the first non-loopback and non-private address
              Enumeration<NetworkInterface> enumeration = NetworkInterface.getNetworkInterfaces();
              ArrayList<String> ipv4Result = new ArrayList<String>();
              ArrayList<String> ipv6Result = new ArrayList<String>();
              while (enumeration.hasMoreElements()) {
                  final NetworkInterface networkInterface = enumeration.nextElement();
                  final Enumeration<InetAddress> en = networkInterface.getInetAddresses();
                  while (en.hasMoreElements()) {
                      final InetAddress address = en.nextElement();
                      if (!address.isLoopbackAddress()) {
                          if (address instanceof Inet6Address) {
                              ipv6Result.add(normalizeHostAddress(address));
                          } else {
                              ipv4Result.add(normalizeHostAddress(address));
                          }
                      }
                  }
              }
  
              // prefer ipv4
              if (!ipv4Result.isEmpty()) {
                  for (String ip : ipv4Result) {
                      if (ip.startsWith("127.0") || ip.startsWith("192.168")) {
                          continue;
                      }
  
                      return ip;
                  }
  
                  return ipv4Result.get(ipv4Result.size() - 1);
              } else if (!ipv6Result.isEmpty()) {
                  return ipv6Result.get(0);
              }
              //If failed to find,fall back to localhost
              final InetAddress localHost = InetAddress.getLocalHost();
              return normalizeHostAddress(localHost);
          } catch (Exception e) {
              log.error("Failed to obtain local address", e);
          }
  
          return null;
      }
  
      public static String normalizeHostAddress(final InetAddress localHost) {
          if (localHost instanceof Inet6Address) {
              return "[" + localHost.getHostAddress() + "]";
          } else {
              return localHost.getHostAddress();
          }
      }
  
      public static SocketAddress string2SocketAddress(final String addr) {
          String[] s = addr.split(":");
          InetSocketAddress isa = new InetSocketAddress(s[0], Integer.parseInt(s[1]));
          return isa;
      }
  
      public static String socketAddress2String(final SocketAddress addr) {
          StringBuilder sb = new StringBuilder();
          InetSocketAddress inetSocketAddress = (InetSocketAddress) addr;
          sb.append(inetSocketAddress.getAddress().getHostAddress());
          sb.append(":");
          sb.append(inetSocketAddress.getPort());
          return sb.toString();
      }
  
      public static SocketChannel connect(SocketAddress remote) {
          return connect(remote, 1000 * 5);
      }
  
      public static SocketChannel connect(SocketAddress remote, final int timeoutMillis) {
          SocketChannel sc = null;
          try {
              sc = SocketChannel.open();
              sc.configureBlocking(true);
              sc.socket().setSoLinger(false, -1);
              sc.socket().setTcpNoDelay(true);
              sc.socket().setReceiveBufferSize(1024 * 64);
              sc.socket().setSendBufferSize(1024 * 64);
              sc.socket().connect(remote, timeoutMillis);
              sc.configureBlocking(false);
              return sc;
          } catch (Exception e) {
              if (sc != null) {
                  try {
                      sc.close();
                  } catch (IOException e1) {
                      e1.printStackTrace();
                  }
              }
          }
  
          return null;
      }
  
  
  }
  