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OpenNMS 1.6.11 » org » opennms » web » InitializerServletContextListener.java
//
//  $Id: InitializerServletContextListener.java 10576 2008-09-18 14:43:43Z rangerrick $
//
// This file is part of the OpenNMS(R) Application.
//
// OpenNMS(R) is Copyright (C) 2002-2003 The OpenNMS Group, Inc.  All
// rights reserved.
// OpenNMS(R) is a derivative work, containing both original code,
// included code and modified code that was published under the GNU
// General Public License. Copyrights for modified and included code
// are below.
//
// OpenNMS(R) is a registered trademark of The OpenNMS Group, Inc.
//
// Modifications:
//
// 2008 May 10: Use log4j for logging. - dj@opennms.org
// 2007 Dec 12: Format comments. - dj@opennms.org
// 2007 Jun 24: Organize imports. - dj@opennms.org
//
// Copyright (C) 1999-2001 Oculan Corp.  All rights reserved.
//
// This program is free software; you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation; either version 2 of the License, or
// (at your option) any later version.
//
// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU General Public License for more details.
//
// You should have received a copy of the GNU General Public License
// along with this program; if not, write to the Free Software
// Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
//
// For more information contact:
//      OpenNMS Licensing       <license@opennms.org>
//      http://www.opennms.org/
//      http://www.opennms.com/
//

package org.opennms.web;

import java.net.ConnectException;
import java.util.Date;
import java.util.Timer;
import java.util.TimerTask;

import javax.servlet.ServletContextEvent;
import javax.servlet.ServletContextListener;
import javax.servlet.ServletException;

import org.apache.log4j.Category;
import org.opennms.core.utils.ThreadCategory;
import org.opennms.netmgt.model.events.EventProxyException;
import org.opennms.web.category.CategoryList;
import org.opennms.web.category.RTCPostSubscriber;

/**
 * Initializes our internal servlet systems at servlet container startup, and
 * destroys any pool resources at servlet container shutdown.
 * 
 * This listener is specified in the web.xml to listen to
 * <code>ServletContext</code> lifecyle events. On startup it calls
 * ServletInitializer.init and initializes the UserFactory, GroupFactory. On
 * shutdown it calls ServletInitializer.destroy.
 * 
 * @author <A HREF="mailto:larry@opennms.org">Lawrence Karnowski </A>
 * @author <A HREF="http://www.opennms.org/">OpenNMS </A>
 */
public class InitializerServletContextListener implements ServletContextListener {

    private Timer rtcCheckTimer = null;

    public void contextInitialized(ServletContextEvent event) {
        try {
            /*
             * Initialize the scarce resource policies (db connections) and
             * common configuration.
             */
            ServletInitializer.init(event.getServletContext());

            log().info("Initialized servlet systems successfully");
        } catch (ServletException e) {
            log().error("Error while initializing servlet systems: " + e, e);
        } catch (Exception e) {
            log().error("Error while initializing user, group, or view factory: " + e, e);
        }

        try {
            rtcCheckTimer = new Timer();
            rtcCheckTimer.schedule(new RTCPostSubscriberTimerTask(), new Date(), 130000);
        } catch (ServletException e) {
            log().error("Error while initializing RTC check timer: " + e, e);
        }
    }

    private Category log() {
        return ThreadCategory.getInstance(getClass());
    }

    public void contextDestroyed(ServletContextEvent event) {
        try {
            /*
             * Let the scarce resource policies release any shared
             * resouces (db connections).
             */
            ServletInitializer.destroy(event.getServletContext());

            // Report success.
            log().info("Destroyed servlet systems successfully");
        } catch (ServletException e) {
            log().error("Error while destroying servlet systems: " + e, e);
        }

        if (rtcCheckTimer != null) {
            rtcCheckTimer.cancel();
            rtcCheckTimer = null;
        }
    }

    public class RTCPostSubscriberTimerTask extends TimerTask {
        private CategoryList m_categorylist;

        public RTCPostSubscriberTimerTask() throws ServletException {
            m_categorylist = new CategoryList();
        }

        public void run() {
            try {
                if (!m_categorylist.isDisconnected()) {
                    return;
                }
            } catch (Exception e) {
                log().error("Error checking if OpenNMS is disconnected: " + e, e);
                return;
            }

            log().info("OpenNMS is disconnected -- attempting RTC POST subscription");

            try {
                RTCPostSubscriber.subscribeAll("WebConsoleView");
                log().info("RTC POST subscription event sent successfully");
            } catch (EventProxyException e) {
                if (e.getCause() instanceof ConnectException) {
                    log().info("RTC POST failed due to ConnectException: " + e.getCause().toString());
                } else {
                    log().error("Error subscribing to RTC POSTs: " + e, e);
                }
            } catch (Exception e) {
                log().error("Error subscribing to RTC POSTs: " + e, e);
            }
        }
        
        private Category log() {
            return ThreadCategory.getInstance(getClass());
        }
    }
}
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