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.broker;
  
  import java.util.Iterator;
  import java.util.Set;
  import java.util.concurrent.CopyOnWriteArraySet;
  import java.util.concurrent.atomic.AtomicBoolean;
  
  import org.apache.activemq.Service;
  import org.apache.activemq.ThreadPriorities;
  import org.slf4j.Logger;
  import org.slf4j.LoggerFactory;
  
  /**
   * Used to provide information on the status of the Connection
   * 
   * 
   */
  public class TransportStatusDetector implements Service, Runnable {
      private static final Logger LOG = LoggerFactory.getLogger(TransportStatusDetector.class);
      private TransportConnector connector;
      private Set<TransportConnection> collectionCandidates = new CopyOnWriteArraySet<TransportConnection>();
      private AtomicBoolean started = new AtomicBoolean(false);
      private Thread runner;
      private int sweepInterval = 5000;
  
      TransportStatusDetector(TransportConnector connector) {
          this.connector = connector;
      }
  
      /**
       * @return Returns the sweepInterval.
       */
      public int getSweepInterval() {
          return sweepInterval;
      }
  
      /**
       * The sweepInterval to set.
       * 
       * @param sweepInterval
       */
      public void setSweepInterval(int sweepInterval) {
          this.sweepInterval = sweepInterval;
      }
  
      protected void doCollection() {
          for (Iterator<TransportConnection> i = collectionCandidates.iterator(); i.hasNext();) {
              TransportConnection tc = i.next();
              if (tc.isMarkedCandidate()) {
                  if (tc.isBlockedCandidate()) {
                      collectionCandidates.remove(tc);
                      doCollection(tc);
                  } else {
                      tc.doMark();
                  }
              } else {
                  collectionCandidates.remove(tc);
              }
          }
      }
  
      protected void doSweep() {
          for (Iterator i = connector.getConnections().iterator(); i.hasNext();) {
              TransportConnection connection = (TransportConnection)i.next();
              if (connection.isMarkedCandidate()) {
                  connection.doMark();
                  collectionCandidates.add(connection);
              }
          }
      }
  
      protected void doCollection(TransportConnection tc) {
          LOG.warn("found a blocked client - stopping: {}", tc);
          try {
              tc.stop();
          } catch (Exception e) {
              LOG.error("Error stopping {}", tc, e);
          }
      }
  
      public void run() {
          while (started.get()) {
              try {
                  doCollection();
                  doSweep();
                  Thread.sleep(sweepInterval);
              } catch (Throwable e) {
                  LOG.error("failed to complete a sweep for blocked clients", e);
              }
          }
      }
  
      public void start() throws Exception {
          if (started.compareAndSet(false, true)) {
              runner = new Thread(this, "ActiveMQ Transport Status Monitor: " + connector);
              runner.setDaemon(true);
              runner.setPriority(ThreadPriorities.BROKER_MANAGEMENT);
              runner.start();
          }
      }
  
      public void stop() throws Exception {
          started.set(false);
          if (runner != null) {
              runner.join(getSweepInterval() * 5L);
          }
      }
  }
  