outageeventcache.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:
//
// 2003 Jan 31: Updated cache to handle when down and up events have same time.
// 2003 Jan 08: Changed SQL "= null" to "is null" to work with Postgres 7.2.
// 
// 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/
//

package org.opennms.netmgt.outage;

import java.text.ParseException;
import java.util.ListIterator;

import org.apache.log4j.Category;
import org.opennms.core.utils.ThreadCategory;
import org.opennms.netmgt.EventConstants;

/**
 * This class will help solve a current intermittant bug where the resolution to
 * an error event is received before the error event itself, due to the database
 * being busy,
 * 
 * If an "up" is received without a matching "down", the event will be saved off
 * to the cache. Thus, when the "down" is received, it can be matched against
 * the events in this cache to see if it has actually been resolved.
 * 
 * @author <A HREF="mailto:[e-mail]">Tarus </A>
 */
public final class OutageEventCache extends java.util.LinkedList {
    /**
     * Singleton instance of the ServiceEventArchive class
     */
    private static final OutageEventCache m_singleton = new OutageEventCache();

    public OutageEventCache() {
        super();
    }

    /**
     * Returns the SelectEventArchive singleton.
     */
    public static OutageEventCache getInstance() {
        return m_singleton;
    }

    /**
     * Adds an object to the cache.
     */
    public boolean add(Object o) {
        synchronized (m_singleton) {
            return super.add(o);
        }
    }

    /**
     * When called, this method will try to find a match for the "unmatched"
     * error event. It will search from least to most severe -> UNRESPONSIVE
     * LOST_SERVICE, INTERFACE_DOWN and NODE_DOWN. If a match is made, the event
     * from the cache is returned, otherwise null.
     * 
     * @param eventId
     *            Event id
     * @param nodeId
     *            Event node ID
     * @param ipAddr
     *            Event IP address
     * @param serviceId
     *            Event service ID
     * @param eventTime
     *            Event timestamp
     * @param type
     *            Event type (service lost, service regained, etc...)
     * 
     * @return the matching entry from the cache
     */
    public OutageEventEntry findCacheMatch(long eventId, long nodeId, String ipAddr, long serviceId, String eventTime, int type) {
        Category log = ThreadCategory.getInstance(getClass());

        java.util.Date serviceLostTime = null;
        try {
            serviceLostTime = EventConstants.parseToDate(eventTime);
        } catch (ParseException e) {
            ThreadCategory.getInstance(this.getClass()).warn("Failed to parse event time: " + eventTime, e);
            return null;
        }

        // Iterate over event cache list and attempt to find
        // a matching entry. If a matching entry is found which
        // meets the criteria then return the entry
        //
        OutageEventEntry cacheEntry = null;
        OutageEventEntry currentEvent = new OutageEventEntry(eventId, nodeId, ipAddr, serviceId, eventTime, type);
        boolean match = false;

        synchronized (m_singleton) {
            ListIterator liter = m_singleton.listIterator();
            while (liter.hasNext() && !match) {
                cacheEntry = (OutageEventEntry) liter.next();

                if (log.isDebugEnabled()) {
                    log.debug("findCacheMatch: cache entry type=" + cacheEntry.getType() + ", lost entry type=" + currentEvent.getType());
                }

                // Now test if cache entry has corresponding event type
                // if specified type is LOST_SERVICE, looking for
                // REGAINED_SERVICE,
                // if specified type is INTERFACE_DOWN, looking for
                // INTERFACE_UP, etc...
                //
                switch (type) {
                case OutageEventEntry.EVENT_TYPE_LOST_SERVICE:
                    // Test to see if there is a cached REGAINED_SERVICE event
                    // that matches this
                    // LOST_SERVICE event in nodeId, IP Address and serviceID.
                    // If so, compare times.
                    // If the REGAINED event occurred after the LOST event, a
                    // match will be made.
                    // Otherwise, if this LOST event matches a cached LOST
                    // event, the cached event
                    // will be deleted.

                    if (cacheEntry.getType() == OutageEventEntry.EVENT_TYPE_REGAINED_SERVICE) {
                        if (cacheEntry.getNodeId() == currentEvent.getNodeId() && cacheEntry.getIpAddr().equals(currentEvent.getIpAddr()) && cacheEntry.getSvcId() == currentEvent.getSvcId()) {
                            java.util.Date serviceRegainedTime = null;
                            try {
                                serviceRegainedTime = EventConstants.parseToDate(cacheEntry.getEventTime());
                            } catch (ParseException e) {
                                ThreadCategory.getInstance(this.getClass()).warn("Failed to parse event time " + cacheEntry.getEventTime(), e);
                                // Remove the entry
                                liter.remove();
                                continue;
                            }

                            if (serviceRegainedTime.after(serviceLostTime) || serviceRegainedTime.equals(serviceLostTime)) {
                                if (log.isDebugEnabled())
                                    log.debug("findCacheMatch: Cache Hit! - Outage will be cleared");
                                match = true;
                                // Remove the entry
                                liter.remove();
                            } else {
                                // Remove the entry
                                liter.remove();
                                continue;
                            }
                        }
                    } else if (cacheEntry.getType() == OutageEventEntry.EVENT_TYPE_LOST_SERVICE) {
                        liter.remove();
                        continue;
                    }
                    break;

                case OutageEventEntry.EVENT_TYPE_INTERFACE_DOWN:
                    // Test to see if there is a cached INTERFACE_UP event that
                    // matches this
                    // INTERFACE_DOWN event in nodeId and IP Address. If so,
                    // compare times.
                    // If the INTERFACE_UP event occurred after the
                    // INTERFACE_DOWN event, a match will be made.
                    // Otherwise, if this INTERFACE_DOWN event matches a cached
                    // INTERFACE_DOWN event, the cached event
                    // will be deleted.

                    if (cacheEntry.getType() == OutageEventEntry.EVENT_TYPE_INTERFACE_UP) {
                        if (cacheEntry.getNodeId() == currentEvent.getNodeId() && cacheEntry.getIpAddr().equals(currentEvent.getIpAddr())) {
                            java.util.Date serviceRegainedTime = null;
                            try {
                                serviceRegainedTime = EventConstants.parseToDate(cacheEntry.getEventTime());
                            } catch (ParseException e) {
                                ThreadCategory.getInstance(this.getClass()).warn("Failed to parse event time " + cacheEntry.getEventTime(), e);
                                // Remove the entry
                                liter.remove();
                                continue;
                            }

                            if (serviceRegainedTime.after(serviceLostTime) || serviceRegainedTime.equals(serviceLostTime)) {
                                if (log.isDebugEnabled())
                                    log.debug("findCacheMatch: Cache Hit! - Outage will be cleared");
                                match = true;
                                // Remove the entry
                                liter.remove();
                            } else {
                                // Remove the entry
                                liter.remove();
                                continue;
                            }
                        }
                    } else if (cacheEntry.getType() == OutageEventEntry.EVENT_TYPE_INTERFACE_DOWN) {
                        liter.remove();
                        continue;
                    }
                    break;

                case OutageEventEntry.EVENT_TYPE_NODE_DOWN:
                    // Test to see if there is a cached NODE_UP event that
                    // matches this
                    // NODE_DOWN event in nodeId. If so, compare times.
                    // If the NODE_UP event occurred after the NODE_DOWN event,
                    // a match will be made.
                    // Otherwise, if this NODE_DOWN event matches a cached
                    // NODE_DOWN event, the cached event
                    // will be deleted.

                    if (cacheEntry.getType() == OutageEventEntry.EVENT_TYPE_NODE_UP) {
                        if (cacheEntry.getNodeId() == currentEvent.getNodeId()) {
                            java.util.Date serviceRegainedTime = null;
                            try {
                                serviceRegainedTime = EventConstants.parseToDate(cacheEntry.getEventTime());
                            } catch (ParseException e) {
                                ThreadCategory.getInstance(this.getClass()).warn("Failed to parse event time " + cacheEntry.getEventTime(), e);
                                // Remove the entry
                                liter.remove();
                                continue;
                            }

                            if (serviceRegainedTime.after(serviceLostTime) || serviceRegainedTime.equals(serviceLostTime)) {
                                if (log.isDebugEnabled())
                                    log.debug("findCacheMatch: Cache Hit! - Outage will be cleared");
                                match = true;
                                // Remove the entry
                                liter.remove();
                            } else {
                                // Remove the entry
                                liter.remove();
                                continue;
                            }
                        }
                    } else if (cacheEntry.getType() == OutageEventEntry.EVENT_TYPE_NODE_DOWN) {
                        liter.remove();
                        continue;
                    }
                    break;

                default:
                    log.warn("findCacheMatch: Unexpected Event - Deleting.");
                    liter.remove();
                    break;
                }
            }

            if (match && cacheEntry != null) {
                return cacheEntry;
            } else {
                return null;
            }

        }
    }
}