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.cloud.api;
  
  import javax.servlet.annotation.WebListener;
  import javax.servlet.http.HttpSession;
  import javax.servlet.http.HttpSessionEvent;
  import javax.servlet.http.HttpSessionListener;
  import org.apache.logging.log4j.Logger;
  import org.apache.logging.log4j.LogManager;
  
  import java.util.Map;
  import java.util.concurrent.ConcurrentHashMap;
  
  @WebListener
  public class ApiSessionListener implements HttpSessionListener {
      protected Logger logger = LogManager.getLogger(getClass());
      private static Map<String, HttpSession> sessions = new ConcurrentHashMap<>();
  
      /**
       * @return the internal administered session count
       */
      public static long getSessionCount() {
          return sessions.size();
      }
  
      /**
       * @return the size of the internal {@see Map} of sessions
       */
      public static long getNumberOfSessions() {
          return sessions.size();
      }
  
      public void sessionCreated(HttpSessionEvent event) {
          if (logger.isDebugEnabled()) {
              logger.debug("Session created by Id : " + event.getSession().getId() + " , session: " + event.getSession().toString() + " , source: " + event.getSource().toString() + " , event: " + event.toString());
          }
          synchronized (this) {
              HttpSession session = event.getSession();
              sessions.put(session.getId(), event.getSession());
          }
          if (logger.isTraceEnabled()) {
              logger.trace("Sessions count: " + getSessionCount());
          }
      }
  
      public void sessionDestroyed(HttpSessionEvent event) {
          if (logger.isDebugEnabled()) {
              logger.debug("Session destroyed by Id : " + event.getSession().getId() + " , session: " + event.getSession().toString() + " , source: " + event.getSource().toString() + " , event: " + event.toString());
          }
          synchronized (this) {
              sessions.remove(event.getSession().getId());
          }
          if (logger.isTraceEnabled()) {
              logger.trace("Sessions count: " + getSessionCount());
          }
      }
  }
  