eventqueueprocessor.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.Enumeration;

import org.apache.log4j.Category;
import org.opennms.core.fiber.PausableFiber;
import org.opennms.core.queue.FifoQueue;
import org.opennms.core.queue.FifoQueueException;
import org.opennms.core.utils.ThreadCategory;
import org.opennms.netmgt.EventConstants;
import org.opennms.netmgt.config.xmlrpcd.XmlrpcServer;
import org.opennms.netmgt.xml.event.Event;
import org.opennms.netmgt.xml.event.Parm;
import org.opennms.netmgt.xml.event.Parms;
import org.opennms.netmgt.xml.event.Value;

/**
 * The EventQueueProcessor processes the events recieved by xmlrpcd and sends
 * notifications to the external XMLRPC server via XMLRPC protocol.
 * 
 * @author <A HREF="mailto:[e-mail]">James Zuo </A>
 * @author <A HREF="http://www.opennms.org">OpenNMS.org </A>
 * 
 */
class EventQueueProcessor implements Runnable, PausableFiber {
    /**
     * The input queue
     */
    private FifoQueue m_eventQ;

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

    /**
     * An object used to communicate with exteranl xmlrpc servers
     */
    private XmlRpcNotifier m_notifier;

    /**
     * Current status of the fiber
     */
    private int m_status;

    /**
     * The thread that is executing the <code>run</code> method on behalf of
     * the fiber.
     */
    private Thread m_worker;

    /**
     * The constructor
     */
    EventQueueProcessor(FifoQueue eventQ, XmlrpcServer[] rpcServers, int retries, int elapseTime, boolean verifyServer, String localServer, int maxQSize) {
        m_eventQ = eventQ;
        m_maxQSize = maxQSize;
        m_notifier = new XmlRpcNotifier(rpcServers, retries, elapseTime, verifyServer, localServer);
    }

    private void processEvent(Event event) {
        Category log = ThreadCategory.getInstance(getClass());

        String uei = event.getUei();
        if (uei == null) {
            // should only get registered events
            if (log.isDebugEnabled())
                log.debug("Event received with null UEI, ignoring event");
            return;
        }

        if (log.isDebugEnabled())
            log.debug("About to process event: " + event.getUei());

        // get eventid
        long eventId = -1;
        if (event.hasDbid())
            eventId = event.getDbid();

        // get node id
        long nodeId = -1;
        if (event.hasNodeid())
            nodeId = event.getNodeid();

        String ipAddr = event.getInterface();
        String service = event.getService();
        String eventTime = event.getTime();

        if (log.isDebugEnabled())
            log.debug("Event\nuei\t\t" + uei + "\neventid\t\t" + eventId + "\nnodeid\t\t" + nodeId + "\nipaddr\t\t" + ipAddr + "\nservice\t\t" + service + "\neventtime\t" + (eventTime != null ? eventTime : "<null>"));

        if (uei.equals(EventConstants.NODE_LOST_SERVICE_EVENT_UEI)) {
            if (!m_notifier.sendServiceDownEvent(event)) {
                pushBackEvent(event);
            }
        } else if (uei.equals(EventConstants.INTERFACE_DOWN_EVENT_UEI)) {
            if (!m_notifier.sendInterfaceDownEvent(event)) {
                pushBackEvent(event);
            }
        } else if (uei.equals(EventConstants.NODE_DOWN_EVENT_UEI)) {
            if (!m_notifier.sendNodeDownEvent(event)) {
                pushBackEvent(event);
            }
        } else if (uei.equals(EventConstants.NODE_UP_EVENT_UEI)) {
            if (!m_notifier.sendNodeUpEvent(event)) {
                pushBackEvent(event);
            }
        } else if (uei.equals(EventConstants.INTERFACE_UP_EVENT_UEI)) {
            if (!m_notifier.sendInterfaceUpEvent(event)) {
                pushBackEvent(event);
            }
        } else if (uei.equals(EventConstants.NODE_REGAINED_SERVICE_EVENT_UEI)) {
            if (!m_notifier.sendServiceUpEvent(event)) {
                pushBackEvent(event);
            }
        } else if (uei.equals(EventConstants.XMLRPC_NOTIFICATION_EVENT_UEI)) {
            xmlrpcNotificationEventHandler(event);
        }
    }

    /**
     * Process xmlrpcNotificationEvent according the status flag to determine to
     * send a notifyReceivedEvent, or a notifySuccess, or a notifyFailure
     * notification to XMLRPC Server.
     */
    private void xmlrpcNotificationEventHandler(Event event) {
        Category log = ThreadCategory.getInstance(getClass());

        long txNo = -1L;
        String sourceUei = null;
        String notification = null;
        int status = -1;

        Parms parms = event.getParms();
        if (parms != null) {
            String parmName = null;
            Value parmValue = null;
            String parmContent = null;

            Enumeration parmEnum = parms.enumerateParm();
            while (parmEnum.hasMoreElements()) {
                Parm parm = (Parm) parmEnum.nextElement();
                parmName = parm.getParmName();
                parmValue = parm.getValue();
                if (parmValue == null)
                    continue;
                else
                    parmContent = parmValue.getContent();

                // get txNo
                if (parmName.equals(EventConstants.PARM_TRANSACTION_NO)) {
                    String temp = parmContent;
                    if (log.isDebugEnabled())
                        log.debug("ParmName: " + parmName + " /parmContent: " + parmContent);

                    try {
                        txNo = Long.valueOf(temp).longValue();
                    } catch (NumberFormatException nfe) {
                        log.warn("Parameter " + EventConstants.PARM_TRANSACTION_NO + " cannot be non-numberic", nfe);
                        txNo = -1L;
                    }
                } else if (parmName.equals(EventConstants.PARM_SOURCE_EVENT_UEI)) {
                    sourceUei = parmContent;
                    if (log.isDebugEnabled())
                        log.debug("ParmName: " + parmName + " /parmContent: " + parmContent);
                } else if (parmName.equals(EventConstants.PARM_SOURCE_EVENT_MESSAGE)) {
                    notification = parmContent;
                    if (log.isDebugEnabled())
                        log.debug("ParmName: " + parmName + " /parmContent: " + parmContent);
                } else if (parmName.equals(EventConstants.PARM_SOURCE_EVENT_STATUS)) {
                    String temp = parmContent;
                    if (log.isDebugEnabled())
                        log.debug("ParmName: " + parmName + " /parmContent: " + parmContent);

                    try {
                        status = Integer.valueOf(temp).intValue();
                    } catch (NumberFormatException nfe) {
                        log.warn("Parameter " + EventConstants.PARM_SOURCE_EVENT_STATUS + " cannot be non-numberic", nfe);
                        status = -1;
                    }
                }

            }
        }

        boolean validParameters = (txNo != -1L) && (sourceUei != null) && (notification != null) && (status != -1);
        if (!validParameters) {
            log.error("Invalid parameters.");
            return;
        }

        switch (status) {
        case EventConstants.XMLRPC_NOTIFY_RECEIVED:
            if (!m_notifier.notifyReceivedEvent(txNo, sourceUei, notification)) {
                pushBackEvent(event);
            }
            break;
        case EventConstants.XMLRPC_NOTIFY_SUCCESS:
            if (!m_notifier.notifySuccess(txNo, sourceUei, notification)) {
                pushBackEvent(event);
            }
            break;
        case EventConstants.XMLRPC_NOTIFY_FAILURE:
            if (!m_notifier.notifyFailure(txNo, sourceUei, notification)) {
                pushBackEvent(event);
            }
        }
    }

    /**
     * Push the event back to the event queue if OpenNMS failed to send message
     * to the external XMLRPC server, so that it could be send to the server
     * again later.
     */
    private void pushBackEvent(Event event) {
        Category log = ThreadCategory.getInstance(getClass());

        // push the event back to the event queue
        try {
            if (m_eventQ.size() < m_maxQSize) {
                m_eventQ.add(event);

                if (log.isDebugEnabled())
                    log.debug("Push the event back to queue.");
            }

            // re-establish connection to xmlrpc servers
            m_notifier.createConnection();
        } catch (FifoQueueException e) {
            log.error("Failed to push the event back to queue", e);
        } catch (InterruptedException e) {
            log.error("Failed to push the event back to queue", e);
        }
    }

    /**
     * Returns true if the status is ok and the thread should continue running.
     * If the status returend is false then the thread should exit.
     * 
     */
    private synchronized boolean statusOK() {
        Category log = ThreadCategory.getInstance(getClass());

        //
        // Loop until there is a new client or we are shutdown
        //
        boolean exitThread = false;
        boolean exitCheck = false;
        while (!exitCheck) {
            //
            // check the child thread!
            //
            if (m_worker.isAlive() == false && m_status != STOP_PENDING) {
                log.warn(getName() + " terminated abnormally");
                m_status = STOP_PENDING;
            }

            //
            // do normal status checks now
            //
            if (m_status == STOP_PENDING) {
                exitCheck = true;
                exitThread = true;
                m_status = STOPPED;
            } else if (m_status == PAUSE_PENDING) {
                pause();
            } else if (m_status == RESUME_PENDING) {
                resume();
            } else if (m_status == PAUSED) {
                try {
                    wait();
                } catch (InterruptedException e) {
                    m_status = STOP_PENDING;
                }
            } else if (m_status == RUNNING) {
                exitCheck = true;
            }

        } // end !exit check

        return !exitThread;

    } // statusOK

    /**
     * Starts the current fiber. If the fiber has already been started,
     * regardless of it's current state, then an IllegalStateException is
     * thrown.
     * 
     * @throws java.lang.IllegalStateException
     *             Thrown if the fiber has already been started.
     * 
     */
    public synchronized void start() {
        Category log = ThreadCategory.getInstance(getClass());

        if (m_worker != null)
            throw new IllegalStateException("The fiber is running or has already run");

        m_status = STARTING;

        m_worker = new Thread(this, getName());
        m_worker.start();

        if (log.isDebugEnabled())
            log.debug(getName() + " started");
    }

    /**
     * Pauses the current fiber.
     */
    public synchronized void pause() {
        if (m_worker == null || m_worker.isAlive() == false)
            throw new IllegalStateException("The fiber is not running");

        m_status = PAUSED;
        notifyAll();
    }

    /**
     * Resumes the currently paused fiber.
     */
    public synchronized void resume() {
        if (m_worker == null || m_worker.isAlive() == false)
            throw new IllegalStateException("The fiber is not running");

        m_status = RUNNING;
        notifyAll();
    }

    /**
     * <p>
     * Stops this fiber. If the fiber has never been started then an
     * <code>IllegalStateExceptio</code> is generated.
     * </p>
     * 
     * @throws java.lang.IllegalStateException
     *             Thrown if the fiber has never been started.
     */
    public synchronized void stop() {
        if (m_worker == null)
            throw new IllegalStateException("The fiber has never run");

        m_status = STOP_PENDING;
        m_worker.interrupt();
        notifyAll();
    }

    /**
     * Returns the name of the fiber.
     * 
     * @return The name of the Fiber.
     */
    public String getName() {
        return "EventQueueProcessor";
    }

    /**
     * Returns the current status of the fiber
     * 
     * @return The status of the Fiber.
     */
    public synchronized int getStatus() {
        if (m_worker != null && !m_worker.isAlive())
            m_status = STOPPED;

        return m_status;
    }

    /**
     * Reads off of the event queue and depends on the uei of the event of read,
     * process the event to send a notification to the external XMLRPC server
     * via XMLRPC protocol.
     * 
     */
    public void run() {
        Category log = ThreadCategory.getInstance(getClass());

        synchronized (this) {
            m_status = RUNNING;
        }

        while (statusOK()) {
            Object obj = null;
            try {
                obj = m_eventQ.remove(1000);
            } catch (InterruptedException iE) {
                log.debug("Caught interrupted exception");
                log.debug(iE.getLocalizedMessage(), iE);

                obj = null;

                m_status = STOP_PENDING;
            } catch (FifoQueueException qE) {
                log.debug("Caught fifo queue exception");
                log.debug(qE.getLocalizedMessage(), qE);

                obj = null;

                m_status = STOP_PENDING;
            }

            if (obj != null && statusOK()) {
                try {
                    processEvent((Event) obj);
                } catch (Throwable t) {
                    log.error("Unexpected error processing event", t);
                }
            }
        }
    }
}