查看本类的 API文档回源码主页

   /*
    * Copyright 2018 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 static io.netty.resolver.dns.DnsAddressDecoder.decodeAddress;
  
  import java.net.InetAddress;
  import java.net.UnknownHostException;
  import java.util.Collections;
  import java.util.List;
  
  import io.netty.channel.Channel;
  import io.netty.channel.EventLoop;
  import io.netty.handler.codec.dns.DnsRecord;
  import io.netty.handler.codec.dns.DnsRecordType;
  import io.netty.util.concurrent.Future;
  import io.netty.util.concurrent.Promise;
  
  final class DnsAddressResolveContext extends DnsResolveContext<InetAddress> {
  
      private final DnsCache resolveCache;
      private final AuthoritativeDnsServerCache authoritativeDnsServerCache;
      private final boolean completeEarlyIfPossible;
  
      DnsAddressResolveContext(DnsNameResolver parent, Channel channel, Future<? extends Channel> channelReadyFuture,
                               Promise<?> originalPromise, String hostname, DnsRecord[] additionals,
                               DnsServerAddressStream nameServerAddrs, int allowedQueries, DnsCache resolveCache,
                               AuthoritativeDnsServerCache authoritativeDnsServerCache,
                               boolean completeEarlyIfPossible) {
          super(parent, channel, channelReadyFuture, originalPromise, hostname, DnsRecord.CLASS_IN,
                parent.resolveRecordTypes(), additionals, nameServerAddrs, allowedQueries);
          this.resolveCache = resolveCache;
          this.authoritativeDnsServerCache = authoritativeDnsServerCache;
          this.completeEarlyIfPossible = completeEarlyIfPossible;
      }
  
      @Override
      DnsResolveContext<InetAddress> newResolverContext(DnsNameResolver parent, Channel channel,
                                                        Future<? extends Channel> channelReadyFuture,
                                                        Promise<?> originalPromise,
                                                        String hostname,
                                                        int dnsClass, DnsRecordType[] expectedTypes,
                                                        DnsRecord[] additionals,
                                                        DnsServerAddressStream nameServerAddrs, int allowedQueries) {
          return new DnsAddressResolveContext(parent, channel, channelReadyFuture, originalPromise, hostname, additionals,
                  nameServerAddrs, allowedQueries, resolveCache, authoritativeDnsServerCache, completeEarlyIfPossible);
      }
  
      @Override
      InetAddress convertRecord(DnsRecord record, String hostname, DnsRecord[] additionals, EventLoop eventLoop) {
          return decodeAddress(record, hostname, parent.isDecodeIdn());
      }
  
      @Override
      List<InetAddress> filterResults(List<InetAddress> unfiltered) {
          Collections.sort(unfiltered, PreferredAddressTypeComparator.comparator(parent.preferredAddressType()));
          return unfiltered;
      }
  
      @Override
      boolean isCompleteEarly(InetAddress resolved) {
          return completeEarlyIfPossible && parent.preferredAddressType().addressType() == resolved.getClass();
      }
  
      @Override
      boolean isDuplicateAllowed() {
          // We don't want include duplicates to mimic JDK behaviour.
          return false;
      }
  
      @Override
      void cache(String hostname, DnsRecord[] additionals,
                 DnsRecord result, InetAddress convertedResult) {
          resolveCache.cache(hostname, additionals, convertedResult, result.timeToLive(), channel().eventLoop());
      }
  
      @Override
      void cache(String hostname, DnsRecord[] additionals, UnknownHostException cause) {
          resolveCache.cache(hostname, additionals, cause, channel().eventLoop());
      }
  
      @Override
      void doSearchDomainQuery(String hostname, Promise<List<InetAddress>> nextPromise) {
          // Query the cache for the hostname first and only do a query if we could not find it in the cache.
          if (!DnsNameResolver.doResolveAllCached(
                  hostname, additionals, nextPromise, resolveCache, parent.resolvedInternetProtocolFamiliesUnsafe())) {
             super.doSearchDomainQuery(hostname, nextPromise);
         }
     }
 
     @Override
     DnsCache resolveCache() {
         return resolveCache;
     }
 
     @Override
     AuthoritativeDnsServerCache authoritativeDnsServerCache() {
         return authoritativeDnsServerCache;
     }
 }