/*

  * This software is licensed under the Apache License, Version 2.0

  * (the "License") agreement; 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 net.admin4j.ui.servlets;

 import javax.servlet.ServletConfig;

 import javax.servlet.ServletException;

 import net.admin4j.config.Admin4JConfiguration;

 import net.admin4j.monitor.BlockedThreadDetector;

 import net.admin4j.util.Daemon;

 import net.admin4j.util.ServletUtils;

 import net.admin4j.util.notify.NotifierUtils;

 /**

  * This servlet will start a thread monitor that will notify administrators of threading issues.

  * <p>Init parameters for this servlet are as follows:</p>

  * <li>sleep.interval.millis -- Optional.  Default 30000 (30 sec).  Amount of time in millis monitor will sleep between checks.</li>

  * <li>max.blocked.threads -- Optional.  Default 2. Number of blocked threads monitor will tolerate before notification.</li>

  * <li>notifier -- Required.  Handles admin notification.  See documentation for the Notifier you're using

  * for any additional configuration requirements.  For example, 'net.admin4j.util.notify.EmailNotifier'.</li>

  * @author D. Ashmore

  * @since 1.0

  */

 public class ThreadMonitorStartupServlet extends Admin4JServlet {

         private static final long serialVersionUID = 591261515058479941L;

         public static final String PUBLIC_HANDLE="thread";

         @SuppressWarnings("unused")

     private static Daemon threadMonitorDaemon = null;

         @Override

         public void init(ServletConfig config) throws ServletException {

             super.init(config);

                 try {                        

                         long sleepIntervalMillis = BlockedThreadDetector.DEFAULT_SLEEP_INTERVAL;

                         int nbrBlockedThreads = BlockedThreadDetector.DEFAULT_BLOCKED_THREAD_THRESHOLD;

                         String sleepIntervalMillisStr = ServletUtils.getConfigurationSetting(

                     new String[]{PUBLIC_HANDLE + ".sleep.interval.millis", 

                     "sleep.interval.millis"}, config);

                         if (sleepIntervalMillisStr != null) {

                                 try {

                     sleepIntervalMillis = Long.parseLong(sleepIntervalMillisStr);

                 } catch (Exception e) {

                     sleepIntervalMillis = BlockedThreadDetector.DEFAULT_SLEEP_INTERVAL;

                     this.logger.error("Invalid sleep.interval.millis parameter for ThreadMonitorStartupServlet.  Default used.  sleep.interval.millis="+ sleepIntervalMillisStr, 

                             e);

                 }

                         }

                         else if ( Admin4JConfiguration.getThreadSleepIntervalMillis() != null ) {

                             sleepIntervalMillis = Admin4JConfiguration.getThreadSleepIntervalMillis();

             }

                         String blockedThreadThresholdStr = ServletUtils.getConfigurationSetting(

                     new String[]{PUBLIC_HANDLE + ".max.blocked.threads", 

                     "max.blocked.threads"}, config);

                         if (blockedThreadThresholdStr != null) {

                                 try {

                     nbrBlockedThreads = Integer.parseInt(blockedThreadThresholdStr);

                 } catch (Exception e) {

                     nbrBlockedThreads = BlockedThreadDetector.DEFAULT_BLOCKED_THREAD_THRESHOLD;

                     this.logger.error("Invalid max.blocked.threads parameter for ThreadMonitorStartupServlet.  Default used.  max.blocked.threads="+ blockedThreadThresholdStr, 

                             e);

                 }

                         }

                         else if ( Admin4JConfiguration.getThreadMaxBlockedThreads() != null ) {

                             nbrBlockedThreads = Admin4JConfiguration.getThreadMaxBlockedThreads();

             }

                         String notifierClassName = config.getInitParameter("notifier");

                         BlockedThreadDetector blockedThreadDetector = new BlockedThreadDetector(

                                 NotifierUtils.configure(config, notifierClassName), 

                                 nbrBlockedThreads);

                         threadMonitorDaemon = new Daemon( blockedThreadDetector, "Admin4j Blocked Thread Detector", sleepIntervalMillis);

                 }

                 catch (Throwable t) {

                         logger.error("Error in boot sequence", t);

                         throw new ServletException(t);

                 }

         }

     /* (non-Javadoc)

      * @see net.admin4j.ui.servlets.Admin4JServlet#hasDisplay()

      */

     @Override

     public boolean hasDisplay() {

         return false;

     }

 }