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.thread;
  
  import org.slf4j.Logger;
  import org.slf4j.LoggerFactory;
  
  /**
   *
   */
  class DedicatedTaskRunner implements TaskRunner {
  
      private static final Logger LOG = LoggerFactory.getLogger(DedicatedTaskRunner.class);
      private final Task task;
      private final Thread thread;
  
      private final Object mutex = new Object();
      private boolean threadTerminated;
      private boolean pending;
      private boolean shutdown;
  
      public DedicatedTaskRunner(final Task task, String name, int priority, boolean daemon) {
          this.task = task;
          thread = new Thread(name) {
              @Override
              public void run() {
                  try {
                      runTask();
                  } finally {
                      LOG.trace("Run task done: {}", task);
                  }
              }
          };
          thread.setDaemon(daemon);
          thread.setName(name);
          thread.setPriority(priority);
          thread.start();
      }
  
      /**
       */
      @Override
      public void wakeup() throws InterruptedException {
          synchronized (mutex) {
              if (shutdown) {
                  return;
              }
              pending = true;
              mutex.notifyAll();
          }
      }
  
      /**
       * shut down the task
       *
       * @param timeout
       * @throws InterruptedException
       */
      @Override
      public void shutdown(long timeout) throws InterruptedException {
          LOG.trace("Shutdown timeout: {} task: {}", timeout, task);
          synchronized (mutex) {
              shutdown = true;
              pending = true;
              mutex.notifyAll();
  
              // Wait till the thread stops ( no need to wait if shutdown
              // is called from thread that is shutting down)
              if (Thread.currentThread() != thread && !threadTerminated) {
                  mutex.wait(timeout);
              }
          }
      }
  
      /**
       * shut down the task
       *
       * @throws InterruptedException
       */
      @Override
      public void shutdown() throws InterruptedException {
          shutdown(0);
      }
  
      final void runTask() {
  
          try {
              while (true) {
  
                  synchronized (mutex) {
                      pending = false;
                      if (shutdown) {
                          return;
                      }
                  }
  
                  LOG.trace("Running task {}", task);
                  if (!task.iterate()) {
                      // wait to be notified.
                      synchronized (mutex) {
                          if (shutdown) {
                              return;
                          }
                          while (!pending) {
                              mutex.wait();
                          }
                      }
                  }
  
              }
  
          } catch (InterruptedException e) {
              // Someone really wants this thread to die off.
              Thread.currentThread().interrupt();
          } finally {
              // Make sure we notify any waiting threads that thread
              // has terminated.
              synchronized (mutex) {
                  threadTerminated = true;
                  mutex.notifyAll();
              }
          }
      }
  }
  