/*
    *  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.mina.filter.keepalive;
  
  import org.apache.mina.core.session.IoSession;
  import org.slf4j.Logger;
  import org.slf4j.LoggerFactory;
  
  /**
   * Tells {@link KeepAliveFilter} what to do when a keep-alive response message
   * was not received within a certain timeout.
   *
   * @author <a href="http://mina.apache.org">Apache MINA Project</a>
   */
  public interface KeepAliveRequestTimeoutHandler {
      /**
       * Do nothing.
       */
      KeepAliveRequestTimeoutHandlerstTimeoutHandler.html#KeepAliveRequestTimeoutHandler">KeepAliveRequestTimeoutHandler NOOP = new KeepAliveRequestTimeoutHandler() {
          public void keepAliveRequestTimedOut(KeepAliveFilter filter, IoSession session) throws Exception {
              // Do nothing.
          }
      };
  
      /**
       * Logs a warning message, but doesn't do anything else.
       */
      KeepAliveRequestTimeoutHandlerestTimeoutHandler.html#KeepAliveRequestTimeoutHandler">KeepAliveRequestTimeoutHandler LOG = new KeepAliveRequestTimeoutHandler() {
          private final Logger LOGGER = LoggerFactory.getLogger(KeepAliveFilter.class);
  
          public void keepAliveRequestTimedOut(KeepAliveFilter filter, IoSession session) throws Exception {
              LOGGER.warn("A keep-alive response message was not received within " + "{} second(s).",
                      filter.getRequestTimeout());
          }
      };
  
      /**
       * Throws a {@link KeepAliveRequestTimeoutException}.
       */
      KeepAliveRequestTimeoutHandlereoutHandler.html#KeepAliveRequestTimeoutHandler">KeepAliveRequestTimeoutHandler EXCEPTION = new KeepAliveRequestTimeoutHandler() {
          public void keepAliveRequestTimedOut(KeepAliveFilter filter, IoSession session) throws Exception {
              throw new KeepAliveRequestTimeoutException("A keep-alive response message was not received within "
                      + filter.getRequestTimeout() + " second(s).");
          }
      };
  
      /**
       * Closes the connection after logging.
       */
      KeepAliveRequestTimeoutHandlertTimeoutHandler.html#KeepAliveRequestTimeoutHandler">KeepAliveRequestTimeoutHandler CLOSE = new KeepAliveRequestTimeoutHandler() {
          private final Logger LOGGER = LoggerFactory.getLogger(KeepAliveFilter.class);
  
          public void keepAliveRequestTimedOut(KeepAliveFilter filter, IoSession session) throws Exception {
              LOGGER.warn("Closing the session because a keep-alive response "
                      + "message was not received within {} second(s).", filter.getRequestTimeout());
              session.closeNow();
          }
      };
  
      /**
       * A special handler for the 'deaf speaker' mode.
       */
      KeepAliveRequestTimeoutHandlertHandler.html#KeepAliveRequestTimeoutHandler">KeepAliveRequestTimeoutHandler DEAF_SPEAKER = new KeepAliveRequestTimeoutHandler() {
          public void keepAliveRequestTimedOut(KeepAliveFilter filter, IoSession session) throws Exception {
              throw new Error("Shouldn't be invoked.  Please file a bug report.");
          }
      };
  
      /**
       * Invoked when {@link KeepAliveFilter} couldn't receive the response for
       * the sent keep alive message.
       * 
       * @param filter The filter to use
       * @param session The current session
       * @throws Exception If anything went wrong
       */
      void keepAliveRequestTimedOut(KeepAliveFilter filter, IoSession session) throws Exception;
  }