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 org.apache.cassandra.transport;
  
  import java.net.InetAddress;
  import java.util.ArrayList;
  import java.util.EnumMap;
  import java.util.List;
  
  import com.github.benmanes.caffeine.cache.Cache;
  import com.github.benmanes.caffeine.cache.Caffeine;
  import com.github.benmanes.caffeine.cache.LoadingCache;
  
  import static org.apache.cassandra.utils.Clock.Global.currentTimeMillis;
  
  /**
   * This class tracks the last 100 connections per protocol version
   */
  public class ProtocolVersionTracker
  {
      private static final int DEFAULT_MAX_CAPACITY = 100;
  
      private final EnumMap<ProtocolVersion, LoadingCache<InetAddress, Long>> clientsByProtocolVersion;
  
      ProtocolVersionTracker()
      {
          this(DEFAULT_MAX_CAPACITY);
      }
  
      private ProtocolVersionTracker(int capacity)
      {
          clientsByProtocolVersion = new EnumMap<>(ProtocolVersion.class);
  
          for (ProtocolVersion version : ProtocolVersion.values())
          {
              clientsByProtocolVersion.put(version, Caffeine.newBuilder().maximumSize(capacity)
                                                            .build(key -> currentTimeMillis()));
          }
      }
  
      void addConnection(InetAddress addr, ProtocolVersion version)
      {
          clientsByProtocolVersion.get(version).put(addr, currentTimeMillis());
      }
  
      List<ClientStat> getAll()
      {
          List<ClientStat> result = new ArrayList<>();
  
          clientsByProtocolVersion.forEach((version, cache) ->
              cache.asMap().forEach((address, lastSeenTime) -> result.add(new ClientStat(address, version, lastSeenTime))));
  
          return result;
      }
  
      List<ClientStat> getAll(ProtocolVersion version)
      {
          List<ClientStat> result = new ArrayList<>();
  
          clientsByProtocolVersion.get(version).asMap().forEach((address, lastSeenTime) ->
              result.add(new ClientStat(address, version, lastSeenTime)));
  
          return result;
      }
  
      public void clear()
      {
          clientsByProtocolVersion.values().forEach(Cache::invalidateAll);
      }
  }
  