content: /*
   * 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 com.alipay.remoting.util;
  
  import java.util.concurrent.ThreadFactory;
  
  import com.alipay.remoting.config.ConfigManager;
  
  import io.netty.bootstrap.ServerBootstrap;
  import io.netty.channel.EventLoopGroup;
  import io.netty.channel.epoll.Epoll;
  import io.netty.channel.epoll.EpollChannelOption;
  import io.netty.channel.epoll.EpollEventLoopGroup;
  import io.netty.channel.epoll.EpollMode;
  import io.netty.channel.epoll.EpollServerSocketChannel;
  import io.netty.channel.epoll.EpollSocketChannel;
  import io.netty.channel.nio.NioEventLoopGroup;
  import io.netty.channel.socket.ServerSocketChannel;
  import io.netty.channel.socket.SocketChannel;
  import io.netty.channel.socket.nio.NioServerSocketChannel;
  import io.netty.channel.socket.nio.NioSocketChannel;
  
  /**
   * Utils for netty EventLoop
   *
   * @author YANGLiiN
   * @version $Id: NettyEventLoopUtil.java, v 1.5 2018-05-28 14:07 YANGLiiN $
   */
  public class NettyEventLoopUtil {
  
      /** check whether epoll enabled, and it would not be changed during runtime. */
      private static boolean epollEnabled = ConfigManager.netty_epoll() && Epoll.isAvailable();
  
      /**
       * Create the right event loop according to current platform and system property, fallback to NIO when epoll not enabled.
       *
       * @param nThreads
       * @param threadFactory
       * @return an EventLoopGroup suitable for the current platform
       */
      public static EventLoopGroup newEventLoopGroup(int nThreads, ThreadFactory threadFactory) {
          return epollEnabled ? new EpollEventLoopGroup(nThreads, threadFactory)
              : new NioEventLoopGroup(nThreads, threadFactory);
      }
  
      /**
       * @return a SocketChannel class suitable for the given EventLoopGroup implementation
       */
      public static Class<? extends SocketChannel> getClientSocketChannelClass() {
          return epollEnabled ? EpollSocketChannel.class : NioSocketChannel.class;
      }
  
      /**
       * @return a ServerSocketChannel class suitable for the given EventLoopGroup implementation
       */
      public static Class<? extends ServerSocketChannel> getServerSocketChannelClass() {
          return epollEnabled ? EpollServerSocketChannel.class : NioServerSocketChannel.class;
      }
  
      /**
       * Use {@link EpollMode#LEVEL_TRIGGERED} for server bootstrap if level trigger enabled by system properties,
       *   otherwise use {@link EpollMode#EDGE_TRIGGERED}.
       * @param serverBootstrap server bootstrap
       */
      public static void enableTriggeredMode(ServerBootstrap serverBootstrap) {
          if (epollEnabled) {
              if (ConfigManager.netty_epoll_lt_enabled()) {
                  serverBootstrap.childOption(EpollChannelOption.EPOLL_MODE,
                      EpollMode.LEVEL_TRIGGERED);
              } else {
                  serverBootstrap
                      .childOption(EpollChannelOption.EPOLL_MODE, EpollMode.EDGE_TRIGGERED);
              }
          }
      }
  }
  