broadcasteventprocessor.java

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//
// 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:
//
// 2004 Jan 13: Added this new code for the XML RPC Daemon
//
// Original code base 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       <[e-mail]>
//      http://www.opennms.org/
//      http://www.opennms.com/
//
// Tab Size = 8
//
package org.opennms.netmgt.xmlrpcd;

import java.util.ArrayList;
import java.util.Enumeration;
import java.util.List;

import org.apache.log4j.Category;
import org.opennms.core.queue.FifoQueue;
import org.opennms.core.queue.FifoQueueException;
import org.opennms.core.utils.ThreadCategory;
import org.opennms.netmgt.config.XmlrpcdConfigFactory;
import org.opennms.netmgt.config.xmlrpcd.SubscribedEvent;
import org.opennms.netmgt.eventd.EventIpcManagerFactory;
import org.opennms.netmgt.eventd.EventListener;
import org.opennms.netmgt.xml.event.Event;

/**
 * 
 * @author <a href="mailto:[e-mail]">James Zuo </a>
 * @author <a href="http://www.opennms.org/">OpenNMS </a>
 */
final class BroadcastEventProcessor implements EventListener {

    /**
     * The location where incoming events of interest are enqueued
     */
    private FifoQueue m_eventQ;

    /**
     * The maximam size of the event queue.
     */
    private int m_maxQSize;

    /**
     * Create message selector to set to the subscription
     */
    BroadcastEventProcessor(FifoQueue eventQ, int maxQSize, Enumeration eventEnum) {
        // Create the selector for the ueis this service is interested in
        //
        List ueiList = new ArrayList();

        while (eventEnum.hasMoreElements()) {
            SubscribedEvent sEvent = (SubscribedEvent) eventEnum.nextElement();
            ueiList.add(sEvent.getUei());
        }

        m_eventQ = eventQ;
        m_maxQSize = maxQSize;
        EventIpcManagerFactory.init();
        EventIpcManagerFactory.getInstance().getManager().addEventListener(this, ueiList);
    }

    /**
     * Unsubscribe from eventd
     */
    public void close() {
        EventIpcManagerFactory.getInstance().getManager().removeEventListener(this);
    }

    /**
     * This method is invoked by the EventIpcManager when a new event is
     * available for processing. Each message is examined for its Universal
     * Event Identifier and the appropriate action is taking based on each UEI.
     * 
     * @param event
     *            The event
     * 
     */
    public void onEvent(Event event) {
        Category log = ThreadCategory.getInstance(getClass());

        String eventUei = event.getUei();
        if (eventUei == null)
            return;

        if (log.isDebugEnabled())
            log.debug("Received event: " + eventUei);

        try {
            if (XmlrpcdConfigFactory.getInstance().eventSubscribed(eventUei)) {
                if (m_eventQ.size() >= m_maxQSize) {
                    m_eventQ.remove(1000);

                    if (log.isDebugEnabled())
                        log.debug("Event " + eventUei + " removed from event queue");
                }

                m_eventQ.add(event);

                if (log.isDebugEnabled())
                    log.debug("Event " + eventUei + " added to event queue");
            }
        } catch (InterruptedException ex) {
            log.error("Failed to process event", ex);
            return;
        } catch (FifoQueueException ex) {
            log.error("Failed to process event", ex);
            return;
        } catch (Throwable t) {
            log.error("Failed to process event", t);
            return;
        }
    }

    /**
     * Return an id for this event listener
     */
    public String getName() {
        return "Xmlrpcd:BroadcastEventProcessor";
    }
}