content: /*
   * Copyright 1999-2018 Alibaba Group Holding Ltd.
   *
   * Licensed 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.alibaba.csp.sentinel.cluster.server.connection;
  
  import java.net.InetSocketAddress;
  import java.util.ArrayList;
  import java.util.List;
  import java.util.Map;
  import java.util.concurrent.ConcurrentHashMap;
  import java.util.concurrent.Executors;
  import java.util.concurrent.ScheduledExecutorService;
  import java.util.concurrent.ScheduledFuture;
  import java.util.concurrent.TimeUnit;
  
  import com.alibaba.csp.sentinel.log.RecordLog;
  
  import io.netty.channel.Channel;
  
  /**
   * Universal connection pool for connection management.
   *
   * @author xuyue
   * @author Eric Zhao
   * @since 1.4.0
   */
  public class ConnectionPool {
  
      @SuppressWarnings("PMD.ThreadPoolCreationRule")
      private static final ScheduledExecutorService TIMER = Executors.newScheduledThreadPool(2);
  
      /**
       * Format: ("ip:port", connection)
       */
      private final Map<String, Connection> CONNECTION_MAP = new ConcurrentHashMap<String, Connection>();
  
      /**
       * Periodic scan task.
       */
      private ScheduledFuture scanTaskFuture = null;
  
      public void createConnection(Channel channel) {
          if (channel != null) {
              Connection connection = new NettyConnection(channel, this);
  
              String connKey = getConnectionKey(channel);
              CONNECTION_MAP.put(connKey, connection);
          }
      }
  
      /**
       * Start the scan task for long-idle connections.
       */
      private synchronized void startScan() {
          if (scanTaskFuture == null
              || scanTaskFuture.isCancelled()
              || scanTaskFuture.isDone()) {
              scanTaskFuture = TIMER.scheduleAtFixedRate(
                  new ScanIdleConnectionTask(this), 10, 30, TimeUnit.SECONDS);
          }
      }
  
      /**
       * Format to "ip:port".
       *
       * @param channel channel
       * @return formatted key
       */
      private String getConnectionKey(Channel channel) {
          InetSocketAddress socketAddress = (InetSocketAddress)channel.remoteAddress();
          String remoteIp = socketAddress.getAddress().getHostAddress();
          int remotePort = socketAddress.getPort();
          return remoteIp + ":" + remotePort;
      }
  
      private String getConnectionKey(String ip, int port) {
          return ip + ":" + port;
      }
  
      public void refreshLastReadTime(Channel channel) {
          if (channel != null) {
              String connKey = getConnectionKey(channel);
              Connection connection = CONNECTION_MAP.get(connKey);
              if (connection != null) {
                  connection.refreshLastReadTime(System.currentTimeMillis());
              }
          }
      }
  
      public Connection getConnection(String remoteIp, int remotePort) {
          String connKey = getConnectionKey(remoteIp, remotePort);
          return CONNECTION_MAP.get(connKey);
      }
  
      public void remove(Channel channel) {
          String connKey = getConnectionKey(channel);
          CONNECTION_MAP.remove(connKey);
      }
  
      public List<Connection> listAllConnection() {
          List<Connection> connections = new ArrayList<Connection>(CONNECTION_MAP.values());
          return connections;
      }
  
      public int count() {
          return CONNECTION_MAP.size();
      }
  
      public void clear() {
          CONNECTION_MAP.clear();
      }
  
      public void shutdownAll() throws Exception {
          for (Connection c : CONNECTION_MAP.values()) {
              c.close();
          }
      }
  
      public void refreshIdleTask() {
          if (scanTaskFuture == null || scanTaskFuture.cancel(false)) {
              startScan();
          } else {
              RecordLog.info("The result of canceling scanTask is error.");
          }
      }
  }
  
  