查看本类的 API文档回源码主页

   /*
    * Copyright 2016 The Netty Project
    *
    * The Netty Project 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:
    *
    *   https://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 io.netty.resolver.dns;
  
  import io.netty.channel.ChannelFactory;
  import io.netty.channel.EventLoop;
  import io.netty.channel.socket.DatagramChannel;
  import io.netty.resolver.AddressResolver;
  import io.netty.resolver.AddressResolverGroup;
  import io.netty.resolver.NameResolver;
  import io.netty.resolver.RoundRobinInetAddressResolver;
  
  import java.net.InetAddress;
  import java.net.InetSocketAddress;
  
  /**
   * A {@link AddressResolverGroup} of {@link DnsNameResolver}s that supports random selection of destination addresses if
   * multiple are provided by the nameserver. This is ideal for use in applications that use a pool of connections, for
   * which connecting to a single resolved address would be inefficient.
   */
  public class RoundRobinDnsAddressResolverGroup extends DnsAddressResolverGroup {
  
      public RoundRobinDnsAddressResolverGroup(DnsNameResolverBuilder dnsResolverBuilder) {
          super(dnsResolverBuilder);
      }
  
      public RoundRobinDnsAddressResolverGroup(
              Class<? extends DatagramChannel> channelType,
              DnsServerAddressStreamProvider nameServerProvider) {
          super(channelType, nameServerProvider);
      }
  
      public RoundRobinDnsAddressResolverGroup(
              ChannelFactory<? extends DatagramChannel> channelFactory,
              DnsServerAddressStreamProvider nameServerProvider) {
          super(channelFactory, nameServerProvider);
      }
  
      /**
       * We need to override this method, not
       * {@link #newNameResolver(EventLoop, ChannelFactory, DnsServerAddressStreamProvider)},
       * because we need to eliminate possible caching of {@link io.netty.resolver.NameResolver#resolve}
       * by {@link InflightNameResolver} created in
       * {@link #newResolver(EventLoop, ChannelFactory, DnsServerAddressStreamProvider)}.
       */
      @Override
      protected final AddressResolver<InetSocketAddress> newAddressResolver(EventLoop eventLoop,
                                                                            NameResolver<InetAddress> resolver)
              throws Exception {
          return new RoundRobinInetAddressResolver(eventLoop, resolver).asAddressResolver();
      }
  }