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.activemq.transport.amqp;
  
  import java.io.IOException;
  import java.util.Timer;
  import java.util.concurrent.RejectedExecutionException;
  import java.util.concurrent.SynchronousQueue;
  import java.util.concurrent.ThreadFactory;
  import java.util.concurrent.ThreadPoolExecutor;
  import java.util.concurrent.TimeUnit;
  import java.util.concurrent.atomic.AtomicBoolean;
  
  import org.apache.activemq.thread.SchedulerTimerTask;
  import org.apache.activemq.transport.AbstractInactivityMonitor;
  import org.apache.activemq.transport.InactivityIOException;
  import org.apache.activemq.transport.Transport;
  import org.apache.activemq.transport.TransportFilter;
  import org.apache.activemq.wireformat.WireFormat;
  import org.slf4j.Logger;
  import org.slf4j.LoggerFactory;
  
  public class AmqpInactivityMonitor extends TransportFilter {
  
      private static final Logger LOG = LoggerFactory.getLogger(AmqpInactivityMonitor.class);
  
      private static ThreadPoolExecutor ASYNC_TASKS;
      private static int CONNECTION_CHECK_TASK_COUNTER;
      private static Timer CONNECTION_CHECK_TASK_TIMER;
      private static int KEEPALIVE_TASK_COUNTER;
      private static Timer KEEPALIVE_TASK_TIMER;
  
      private final AtomicBoolean failed = new AtomicBoolean(false);
      private AmqpTransport amqpTransport;
  
      private long connectionTimeout = AmqpWireFormat.DEFAULT_CONNECTION_TIMEOUT;
  
      private SchedulerTimerTask connectCheckerTask;
      private final Runnable connectChecker = new Runnable() {
  
          private final long startTime = System.currentTimeMillis();
  
          @Override
          public void run() {
              long now = System.currentTimeMillis();
  
              if ((now - startTime) >= connectionTimeout && connectCheckerTask != null && !ASYNC_TASKS.isShutdown()) {
                  LOG.debug("No connection attempt made in time for {}! Throwing InactivityIOException.", AmqpInactivityMonitor.this.toString());
                  try {
                      ASYNC_TASKS.execute(new Runnable() {
                          @Override
                          public void run() {
                              onException(new InactivityIOException(
                                  "Channel was inactive for too (>" + (connectionTimeout) + ") long: " + next.getRemoteAddress()));
                          }
                      });
                  } catch (RejectedExecutionException ex) {
                      if (!ASYNC_TASKS.isShutdown()) {
                          LOG.error("Async connection timeout task was rejected from the executor: ", ex);
                          throw ex;
                      }
                  }
              }
          }
      };
  
      private SchedulerTimerTask keepAliveTask;
      private final Runnable keepAlive = new Runnable() {
  
          @Override
          public void run() {
              if (keepAliveTask != null && !ASYNC_TASKS.isShutdown()) {
                  try {
                      ASYNC_TASKS.execute(new Runnable() {
                          @Override
                          public void run() {
                              try {
                                  long nextIdleUpdate = amqpTransport.keepAlive();
                                  if (nextIdleUpdate > 0) {
                                      synchronized (AmqpInactivityMonitor.this) {
                                          if (keepAliveTask != null) {
                                              keepAliveTask = new SchedulerTimerTask(keepAlive);
                                              KEEPALIVE_TASK_TIMER.schedule(keepAliveTask, nextIdleUpdate);
                                          }
                                      }
                                  }
                              } catch (Exception ex) {
                                  onException(new InactivityIOException(
                                      "Exception while performing idle checks for connection: " + next.getRemoteAddress()));
                              }
                          }
                      });
                  } catch (RejectedExecutionException ex) {
                      if (!ASYNC_TASKS.isShutdown()) {
                          LOG.error("Async connection timeout task was rejected from the executor: ", ex);
                          throw ex;
                      }
                  }
              }
          }
      };
  
      public AmqpInactivityMonitor(Transport next, WireFormat wireFormat) {
          super(next);
      }
  
      @Override
      public void start() throws Exception {
          next.start();
      }
  
      @Override
      public void stop() throws Exception {
          stopConnectionTimeoutChecker();
          stopKeepAliveTask();
          next.stop();
      }
  
      @Override
      public void onException(IOException error) {
          if (failed.compareAndSet(false, true)) {
              stopConnectionTimeoutChecker();
              if (amqpTransport != null) {
                  amqpTransport.onException(error);
              }
              transportListener.onException(error);
          }
      }
  
      public void setAmqpTransport(AmqpTransport amqpTransport) {
          this.amqpTransport = amqpTransport;
      }
  
      public AmqpTransport getAmqpTransport() {
          return amqpTransport;
      }
  
      public synchronized void startConnectionTimeoutChecker(long connectionTimeout) {
          this.connectionTimeout = connectionTimeout;
          if (connectionTimeout > 0 && connectCheckerTask == null) {
              connectCheckerTask = new SchedulerTimerTask(connectChecker);
  
              long connectionCheckInterval = Math.min(connectionTimeout, 1000);
  
              synchronized (AbstractInactivityMonitor.class) {
                  if (CONNECTION_CHECK_TASK_COUNTER == 0) {
                      if (ASYNC_TASKS == null || ASYNC_TASKS.isShutdown()) {
                          ASYNC_TASKS = createExecutor();
                      }
                      CONNECTION_CHECK_TASK_TIMER = new Timer("AMQP InactivityMonitor State Check", true);
                  }
                  CONNECTION_CHECK_TASK_COUNTER++;
                  CONNECTION_CHECK_TASK_TIMER.schedule(connectCheckerTask, connectionCheckInterval, connectionCheckInterval);
              }
          }
      }
  
      /**
       * Starts the keep alive task which will run after the given delay.
       *
       * @param nextKeepAliveCheck
       *        time in milliseconds to wait before performing the next keep-alive check.
       */
      public synchronized void startKeepAliveTask(long nextKeepAliveCheck) {
          if (nextKeepAliveCheck > 0 && keepAliveTask == null) {
              keepAliveTask = new SchedulerTimerTask(keepAlive);
  
              synchronized (AbstractInactivityMonitor.class) {
                  if (KEEPALIVE_TASK_COUNTER == 0) {
                      if (ASYNC_TASKS == null || ASYNC_TASKS.isShutdown()) {
                          ASYNC_TASKS = createExecutor();
                      }
                      KEEPALIVE_TASK_TIMER = new Timer("AMQP InactivityMonitor Idle Update", true);
                  }
                  KEEPALIVE_TASK_COUNTER++;
                  KEEPALIVE_TASK_TIMER.schedule(keepAliveTask, nextKeepAliveCheck);
              }
          }
      }
  
      public synchronized void stopConnectionTimeoutChecker() {
          if (connectCheckerTask != null) {
              connectCheckerTask.cancel();
              connectCheckerTask = null;
  
              synchronized (AbstractInactivityMonitor.class) {
                  CONNECTION_CHECK_TASK_TIMER.purge();
                  CONNECTION_CHECK_TASK_COUNTER--;
                  if (CONNECTION_CHECK_TASK_COUNTER == 0) {
                      CONNECTION_CHECK_TASK_TIMER.cancel();
                      CONNECTION_CHECK_TASK_TIMER = null;
                  }
              }
          }
      }
  
      public synchronized void stopKeepAliveTask() {
          if (keepAliveTask != null) {
              keepAliveTask.cancel();
              keepAliveTask = null;
  
              synchronized (AbstractInactivityMonitor.class) {
                  KEEPALIVE_TASK_TIMER.purge();
                  KEEPALIVE_TASK_COUNTER--;
                  if (KEEPALIVE_TASK_COUNTER == 0) {
                      KEEPALIVE_TASK_TIMER.cancel();
                      KEEPALIVE_TASK_TIMER = null;
                  }
              }
          }
      }
  
      private final ThreadFactory factory = new ThreadFactory() {
          @Override
          public Thread newThread(Runnable runnable) {
              Thread thread = new Thread(runnable, "AmqpInactivityMonitor Async Task: " + runnable);
              thread.setDaemon(true);
              return thread;
          }
      };
  
      private ThreadPoolExecutor createExecutor() {
          ThreadPoolExecutor exec = new ThreadPoolExecutor(0, Integer.MAX_VALUE, 90, TimeUnit.SECONDS, new SynchronousQueue<Runnable>(), factory);
          exec.allowCoreThreadTimeOut(true);
          return exec;
      }
  }
  