client/monitors/Heartbeat__Monitor.java

/* 
 * i-scream central monitoring system
 * http://www.i-scream.org.uk
 * Copyright (C) 2000-2002 i-scream
 * 
 * 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.
 */

//---PACKAGE DECLARATION---
package uk.org.iscream.cms.server.client.monitors;

//---IMPORTS---
import java.util.HashMap;
import java.util.Iterator;
import java.util.StringTokenizer;
import uk.org.iscream.cms.server.client.*;
import uk.org.iscream.cms.server.core.*;
import uk.org.iscream.cms.util.*;
import uk.org.iscream.cms.server.componentmanager.*;

/**
 * This Monitor watches heartbeats.
 * It generates an alert when a heartbeat that is expected
 * does not arrive. Unlike all the other monitors, this one
 * is driven by an event *not* occuring, rather than an
 * event occuring. This means it must be actively checking
 * for missing heartbeat's, and thus has an extra inner class
 * thread.
 *
 * @author  $Author: tdb $
 * @version $Id: Heartbeat__Monitor.java,v 1.23 2002/05/21 16:47:16 tdb Exp $
 */
public class Heartbeat__Monitor extends MonitorSkeleton {

//---FINAL ATTRIBUTES---

    /**
     * The current CVS revision of this class
     */
    public final String REVISION = "$Revision: 1.23 $";
    
    /**
     * A description of this monitor
     */
    public final String DESC = "Monitors Heartbeats.";
    
    /**
     * The default (used if not configured) period at
     * which to check for old heartbeats. (in seconds)
     */
    public final int DEFAULT_CHECK_PERIOD = 60;
    
//---STATIC METHODS---

//---CONSTRUCTORS---
    
    /**
     * Constructs a new Heartbeat monitor, and starts off
     * the worker thread.
     */
    public Heartbeat__Monitor() {
        super();
        createInitialHosts();
        new HeartbeatWorker().start();
    }

//---PUBLIC METHODS---
    
    /**
     * Analyse a packet of data. In this case, this will just
     * register the fact that a heartbeat has arrived.
     *
     * @param packet The packet of data to analyse
     */
    public void analysePacket(XMLPacket packet) {
        String source = packet.getParam("packet.attributes.machine_name");
        if (!_hosts.containsKey(source)) {
            synchronized(this) {
                _hosts.put(source, new HeartbeatHolder(new Register(source, _name)));
            }
        }
        HeartbeatHolder lastHeartbeat = (HeartbeatHolder) _hosts.get(source);
        lastHeartbeat.setLastHeartbeat(System.currentTimeMillis()/1000);
    }
    
    /**
     * Overrides the {@link java.lang.Object#toString() Object.toString()}
     * method to provide clean logging (every class should have this).
     *
     * This uses the uk.org.iscream.cms.util.NameFormat class
     * to format the toString()
     *
     * @return the name of this class and its CVS revision
     */
    public String toString() {
        return FormatName.getName(
            _name,
            getClass().getName(),
            REVISION);
    }

    /**
     * return the String representation of what the monitor does
     */
    public String getDescription(){
        return DESC;
    }

//---PRIVATE METHODS---
    
    /**
     * Checks whether the time since the last heartbeat
     * is beyond the threshold(s).
     *
     * @param timeSinceLastHB a long time since the last heartbeat arrived
     * @param reg the Register for this host
     * @return the level which has been breached, if any
     */
    private int checkAttributeThreshold(long timeSinceLastHB, Register reg) {
        for(int thresholdLevel = Alert.thresholdLevels.length - 1; thresholdLevel >= 0; thresholdLevel--) {
            if (reg.getThreshold(thresholdLevel) != -1.0) {
                if (((long) reg.getThreshold(thresholdLevel)) < timeSinceLastHB) {
                    return thresholdLevel;
                }
            }
        }
        return Alert.thresholdNORMAL;
    }
    
    /**
     * Gets an initial list of hosts from the config
     * and adds a fake set of heartbeats for them.
     * If the hosts don't respond within the timeout
     * period an alert will be raised.
     *
     * The effect of this is to allow us to know about
     * hosts which weren't on when we started up, and
     * will thus never have generated a heartbeat - yet
     * will still want to know they're not responding.
     */
    private void createInitialHosts() {
        // get the initial list of hosts from the config
        String initialHosts = "";
        try {
            initialHosts = _cp.getProperty(_name, "Monitor.Heartbeat.initialHosts");
        } catch (PropertyNotFoundException e) {
            // just leave initialHosts empty
            _logger.write(Heartbeat__Monitor.this.toString(), Logger.DEBUG, "No initial list of hosts set, defaulting to none.");
        }
        
        // parse through the initial hosts adding them
        StringTokenizer st = new StringTokenizer(initialHosts, ";");
        while (st.hasMoreTokens()) {
            String source = st.nextToken();
            // check if they already exist, don't want to add them twice
            if (!_hosts.containsKey(source)) {
                synchronized(this) {
                    _hosts.put(source, new HeartbeatHolder(new Register(source, _name)));
                }
            }
            HeartbeatHolder lastHeartbeat = (HeartbeatHolder) _hosts.get(source);
            // set a "fake" heartbeat
            lastHeartbeat.setLastHeartbeat(System.currentTimeMillis()/1000);
        }
    }

//---ACCESSOR/MUTATOR METHODS---
    
    /**
     * Returns a reference to the Queue we're getting data
     * from. This is specific to this monitor.
     *
     * @return a reference to a Queue to get data from
     */
    protected Queue getQueue() {
        return MonitorManager.getInstance().getHeartbeatQueue();
    }
    
//---ATTRIBUTES---

    /**
     * This is the friendly identifier of the
     * component this class is running in.
     * eg, a Filter may be called "filter1",
     * If this class does not have an owning
     * component,  a name from the configuration
     * can be placed here.  This name could also
     * be changed to null for utility classes.
     */
    private String _name = "Heartbeat";
    
    /**
     * A reference to the configuration proxy in use
     */
    private ConfigurationProxy _cp = ConfigurationProxy.getInstance();
    
    /**
     * A HashMap of hosts, with associated HeartbeatHolder's.
     */
    private HashMap _hosts = new HashMap();
    
    /**
     * A reference to the system logger.
     */
    private Logger _logger = ReferenceManager.getInstance().getLogger();

//---STATIC ATTRIBUTES---

//---INNER CLASSES---
    
    /**
     * This inner class simply holding some information
     * about a specific host.
     */
    private class HeartbeatHolder {
        
        /**
         * Construct a new HeartbeatHolder.
         */
        public HeartbeatHolder(Register register) {
            _register = register;
        }
        
        /**
         * Set the time of the last heartbeat
         */
        public void setLastHeartbeat(long lastHeartbeat) {
            _lastHeartbeat = lastHeartbeat;
        }
        
        /**
         * Get the time of the last heartbeat
         */
        public long getLastHeartbeat() {
            return _lastHeartbeat;
        }
        
        /**
         * Get the Register
         */
        public Register getRegister() {
            return _register;
        }
        
        /**
         * last heartbeat time
         */
        private long _lastHeartbeat;
        
        /**
         * register ref
         */
        private Register _register;
    }
    
    /**
     * This worker thread just checks all the hosts and then
     * waits a period of time before doing it again. It sends
     * Alerts as required.
     */
    private class HeartbeatWorker extends Thread {
        
        /**
         * The main run method of this worker thread. It simply
         * checks through all the hosts it has stored, running
         * the analyseHB method on each. It then removes any
         * that have passed a FINAL, and waits a (configured)
         * length of time before doing it again.
         */
        public void run() {
            ConfigurationProxy cp = ConfigurationProxy.getInstance();
            while(true) {
                // this cycle period of this monitor's checks
                int checkPeriod = 0;
                try {
                    checkPeriod = Integer.parseInt(cp.getProperty(_name, "Monitor.Heartbeat.checkPeriod"));
                } catch (PropertyNotFoundException e) {
                    checkPeriod = DEFAULT_CHECK_PERIOD;
                    _logger.write(Heartbeat__Monitor.this.toString(), Logger.WARNING, "Monitor.Heartbeat.checkPeriod value unavailable using default of " + checkPeriod + " seconds");
                } catch (NumberFormatException e) {
                    checkPeriod = DEFAULT_CHECK_PERIOD;
                    _logger.write(Heartbeat__Monitor.this.toString(), Logger.WARNING, "Erronous Monitor.Heartbeat.checkPeriod value in configuration using default of " + checkPeriod + " seconds");
                }
                
                synchronized(Heartbeat__Monitor.this) {
                    // perform the checks (use HB hash, although they *should* be the same)
                    Iterator i = _hosts.keySet().iterator();
                    while(i.hasNext()) {
                        // get host
                        String source = (String) i.next();
                        // check it
                        boolean remove = analyseHB(source);
                        // remove it if it's passed a FINAL
                        if(remove) {
                            i.remove();
                        }
                    }
                }
                
                // wait a while
                try {Thread.sleep(checkPeriod * 1000);} catch (InterruptedException e) {}
            }
        }
        
        /**
         * Analyses a given host's state, and if need be generates
         * a relevant Alert. Note that it also checks if the last
         * alert sent is FINAL, in which case it returns true to
         * indicate removal of this host.
         *
         * @param source the host to check
         * @return whether this host can be deleted
         */
        private boolean analyseHB(String source) {
            ConfigurationProxy cp = ConfigurationProxy.getInstance();
            HeartbeatHolder hbHolder = (HeartbeatHolder) _hosts.get(source);
            Register reg = hbHolder.getRegister();
            
            // get host's HB interval (seconds)
            // this should always exist, thus we set to 0
            int hostHBinterval = 0;
            try {
                hostHBinterval = Integer.parseInt(cp.getProperty("Host."+source, "Host.TCPUpdateTime"));
            } catch (PropertyNotFoundException e) {
                hostHBinterval = 0;
                _logger.write(Heartbeat__Monitor.this.toString(), Logger.WARNING, "TCPUpdateTime value unavailable using default of " + hostHBinterval + " seconds");
            } catch (NumberFormatException e) {
                hostHBinterval = 0;
                _logger.write(Heartbeat__Monitor.this.toString(), Logger.WARNING, "Erronous TCPUpdateTime value in configuration using default of " + hostHBinterval + " seconds");
            }
            
            // get host's last HB time (seconds)
            long lastHeartbeat = hbHolder.getLastHeartbeat();
            // time since last heartbeat (seconds)
            long timeSinceLastHB = (System.currentTimeMillis()/1000) - lastHeartbeat;
            // time since (or until if negative) the expected heartbeat
            long timeSinceExpectedHB = timeSinceLastHB - (long) hostHBinterval;
            
            // best do a check in case the expected heartbeat is in the future
            if(timeSinceExpectedHB < 0) {
                timeSinceExpectedHB = 0;
            }
            
            // find out the threshold level we're at
            int newThreshold = checkAttributeThreshold(timeSinceExpectedHB, reg);
            
            // process the alert
            Heartbeat__Monitor.this.processAlert(newThreshold, "Heartbeat", reg, source, String.valueOf(timeSinceExpectedHB));
            
            if(reg.getLastAlertLevel() == Alert.alertFINAL) {
                return true;
            }
            return false;
        }
    }
}
Revision:	1.24
Committed:	Wed Feb 5 16:43:45 2003 UTC (22 years, 10 months ago) by tdb
Branch:	MAIN
Changes since 1.23:	+4 -4 lines
Log Message:	Changed the server to use the external util package. Quite a minor change, but does affect a lot of files.
#	User	Rev	Content
1	tdb	1.22	/*
2			* i-scream central monitoring system
3	tdb	1.23	* http://www.i-scream.org.uk
4	tdb	1.22	* Copyright (C) 2000-2002 i-scream
5			*
6			* This program is free software; you can redistribute it and/or
7			* modify it under the terms of the GNU General Public License
8			* as published by the Free Software Foundation; either version 2
9			* of the License, or (at your option) any later version.
10			*
11			* This program is distributed in the hope that it will be useful,
12			* but WITHOUT ANY WARRANTY; without even the implied warranty of
13			* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14			* GNU General Public License for more details.
15			*
16			* You should have received a copy of the GNU General Public License
17			* along with this program; if not, write to the Free Software
18			* Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
19			*/
20
21	tdb	1.1	//---PACKAGE DECLARATION---
22	tdb	1.20	package uk.org.iscream.cms.server.client.monitors;
23	tdb	1.1
24			//---IMPORTS---
25			import java.util.HashMap;
26			import java.util.Iterator;
27	tdb	1.21	import java.util.StringTokenizer;
28	tdb	1.20	import uk.org.iscream.cms.server.client.*;
29			import uk.org.iscream.cms.server.core.*;
30	tdb	1.24	import uk.org.iscream.cms.util.*;
31	tdb	1.20	import uk.org.iscream.cms.server.componentmanager.*;
32	tdb	1.1
33			/**
34	tdb	1.18	* This Monitor watches heartbeats.
35			* It generates an alert when a heartbeat that is expected
36			* does not arrive. Unlike all the other monitors, this one
37			* is driven by an event not occuring, rather than an
38			* event occuring. This means it must be actively checking
39			* for missing heartbeat's, and thus has an extra inner class
40			* thread.
41	tdb	1.1	*
42	tdb	1.22	* @author $Author: tdb $
43	tdb	1.24	* @version $Id: Heartbeat__Monitor.java,v 1.23 2002/05/21 16:47:16 tdb Exp $
44	tdb	1.1	*/
45	ajm	1.14	public class Heartbeat__Monitor extends MonitorSkeleton {
46	tdb	1.1
47			//---FINAL ATTRIBUTES---
48
49			/**
50			* The current CVS revision of this class
51			*/
52	tdb	1.24	public final String REVISION = "$Revision: 1.23 $";
53	tdb	1.1
54	tdb	1.18	/**
55			* A description of this monitor
56			*/
57	tdb	1.1	public final String DESC = "Monitors Heartbeats.";
58
59	tdb	1.18	/**
60			* The default (used if not configured) period at
61			* which to check for old heartbeats. (in seconds)
62			*/
63	tdb	1.3	public final int DEFAULT_CHECK_PERIOD = 60;
64
65	tdb	1.1	//---STATIC METHODS---
66
67			//---CONSTRUCTORS---
68	tdb	1.18
69			/**
70			* Constructs a new Heartbeat monitor, and starts off
71			* the worker thread.
72			*/
73	tdb	1.2	public Heartbeat__Monitor() {
74	ajm	1.16	super();
75	tdb	1.21	createInitialHosts();
76	ajm	1.14	new HeartbeatWorker().start();
77	tdb	1.2	}
78
79	tdb	1.1	//---PUBLIC METHODS---
80
81	tdb	1.18	/**
82			* Analyse a packet of data. In this case, this will just
83			* register the fact that a heartbeat has arrived.
84			*
85			* @param packet The packet of data to analyse
86			*/
87	ajm	1.14	public void analysePacket(XMLPacket packet) {
88			String source = packet.getParam("packet.attributes.machine_name");
89			if (!_hosts.containsKey(source)) {
90	tdb	1.9	synchronized(this) {
91	tdb	1.18	_hosts.put(source, new HeartbeatHolder(new Register(source, _name)));
92	tdb	1.1	}
93			}
94	ajm	1.14	HeartbeatHolder lastHeartbeat = (HeartbeatHolder) _hosts.get(source);
95			lastHeartbeat.setLastHeartbeat(System.currentTimeMillis()/1000);
96	tdb	1.1	}
97
98			/**
99			* Overrides the {@link java.lang.Object#toString() Object.toString()}
100			* method to provide clean logging (every class should have this).
101			*
102	tdb	1.24	* This uses the uk.org.iscream.cms.util.NameFormat class
103	tdb	1.1	* to format the toString()
104			*
105			* @return the name of this class and its CVS revision
106			*/
107			public String toString() {
108			return FormatName.getName(
109			_name,
110			getClass().getName(),
111			REVISION);
112			}
113
114			/**
115			* return the String representation of what the monitor does
116			*/
117			public String getDescription(){
118			return DESC;
119			}
120
121			//---PRIVATE METHODS---
122
123	tdb	1.18	/**
124			* Checks whether the time since the last heartbeat
125			* is beyond the threshold(s).
126			*
127			* @param timeSinceLastHB a long time since the last heartbeat arrived
128			* @param reg the Register for this host
129			* @return the level which has been breached, if any
130			*/
131	tdb	1.2	private int checkAttributeThreshold(long timeSinceLastHB, Register reg) {
132	tdb	1.1	for(int thresholdLevel = Alert.thresholdLevels.length - 1; thresholdLevel >= 0; thresholdLevel--) {
133			if (reg.getThreshold(thresholdLevel) != -1.0) {
134	tdb	1.2	if (((long) reg.getThreshold(thresholdLevel)) < timeSinceLastHB) {
135	tdb	1.1	return thresholdLevel;
136			}
137			}
138			}
139	tdb	1.7	return Alert.thresholdNORMAL;
140	tdb	1.21	}
141
142			/**
143			* Gets an initial list of hosts from the config
144			* and adds a fake set of heartbeats for them.
145			* If the hosts don't respond within the timeout
146			* period an alert will be raised.
147			*
148			* The effect of this is to allow us to know about
149			* hosts which weren't on when we started up, and
150			* will thus never have generated a heartbeat - yet
151			* will still want to know they're not responding.
152			*/
153			private void createInitialHosts() {
154			// get the initial list of hosts from the config
155			String initialHosts = "";
156			try {
157			initialHosts = _cp.getProperty(_name, "Monitor.Heartbeat.initialHosts");
158			} catch (PropertyNotFoundException e) {
159			// just leave initialHosts empty
160			_logger.write(Heartbeat__Monitor.this.toString(), Logger.DEBUG, "No initial list of hosts set, defaulting to none.");
161			}
162
163			// parse through the initial hosts adding them
164			StringTokenizer st = new StringTokenizer(initialHosts, ";");
165			while (st.hasMoreTokens()) {
166			String source = st.nextToken();
167			// check if they already exist, don't want to add them twice
168			if (!_hosts.containsKey(source)) {
169			synchronized(this) {
170			_hosts.put(source, new HeartbeatHolder(new Register(source, _name)));
171			}
172			}
173			HeartbeatHolder lastHeartbeat = (HeartbeatHolder) _hosts.get(source);
174			// set a "fake" heartbeat
175			lastHeartbeat.setLastHeartbeat(System.currentTimeMillis()/1000);
176			}
177	tdb	1.1	}
178
179			//---ACCESSOR/MUTATOR METHODS---
180	tdb	1.18
181			/**
182			* Returns a reference to the Queue we're getting data
183			* from. This is specific to this monitor.
184			*
185			* @return a reference to a Queue to get data from
186			*/
187	ajm	1.14	protected Queue getQueue() {
188			return MonitorManager.getInstance().getHeartbeatQueue();
189			}
190
191	tdb	1.1	//---ATTRIBUTES---
192
193			/**
194			* This is the friendly identifier of the
195			* component this class is running in.
196			* eg, a Filter may be called "filter1",
197			* If this class does not have an owning
198			* component, a name from the configuration
199			* can be placed here. This name could also
200			* be changed to null for utility classes.
201			*/
202			private String _name = "Heartbeat";
203
204			/**
205			* A reference to the configuration proxy in use
206			*/
207			private ConfigurationProxy _cp = ConfigurationProxy.getInstance();
208	tdb	1.18
209			/**
210			* A HashMap of hosts, with associated HeartbeatHolder's.
211			*/
212	tdb	1.6	private HashMap _hosts = new HashMap();
213	tdb	1.18
214			/**
215			* A reference to the system logger.
216			*/
217	tdb	1.15	private Logger _logger = ReferenceManager.getInstance().getLogger();
218	tdb	1.1
219			//---STATIC ATTRIBUTES---
220
221			//---INNER CLASSES---
222	tdb	1.18
223			/**
224			* This inner class simply holding some information
225			* about a specific host.
226			*/
227	tdb	1.1	private class HeartbeatHolder {
228
229	tdb	1.18	/**
230			* Construct a new HeartbeatHolder.
231			*/
232			public HeartbeatHolder(Register register) {
233			_register = register;
234	tdb	1.6	}
235
236	tdb	1.18	/**
237			* Set the time of the last heartbeat
238			*/
239	tdb	1.2	public void setLastHeartbeat(long lastHeartbeat) {
240	tdb	1.1	_lastHeartbeat = lastHeartbeat;
241			}
242
243	tdb	1.18	/**
244			* Get the time of the last heartbeat
245			*/
246	tdb	1.2	public long getLastHeartbeat() {
247	tdb	1.1	return _lastHeartbeat;
248			}
249
250	tdb	1.18	/**
251			* Get the Register
252			*/
253			public Register getRegister() {
254			return _register;
255	tdb	1.6	}
256
257	tdb	1.18	/**
258			* last heartbeat time
259			*/
260	tdb	1.2	private long _lastHeartbeat;
261	tdb	1.18
262			/**
263			* register ref
264			*/
265			private Register _register;
266	ajm	1.14	}
267
268	tdb	1.18	/**
269			* This worker thread just checks all the hosts and then
270			* waits a period of time before doing it again. It sends
271			* Alerts as required.
272			*/
273	ajm	1.14	private class HeartbeatWorker extends Thread {
274
275	tdb	1.18	/**
276			* The main run method of this worker thread. It simply
277			* checks through all the hosts it has stored, running
278			* the analyseHB method on each. It then removes any
279			* that have passed a FINAL, and waits a (configured)
280			* length of time before doing it again.
281			*/
282	ajm	1.14	public void run() {
283			ConfigurationProxy cp = ConfigurationProxy.getInstance();
284			while(true) {
285			// this cycle period of this monitor's checks
286			int checkPeriod = 0;
287			try {
288			checkPeriod = Integer.parseInt(cp.getProperty(_name, "Monitor.Heartbeat.checkPeriod"));
289			} catch (PropertyNotFoundException e) {
290			checkPeriod = DEFAULT_CHECK_PERIOD;
291	tdb	1.19	_logger.write(Heartbeat__Monitor.this.toString(), Logger.WARNING, "Monitor.Heartbeat.checkPeriod value unavailable using default of " + checkPeriod + " seconds");
292	ajm	1.14	} catch (NumberFormatException e) {
293			checkPeriod = DEFAULT_CHECK_PERIOD;
294	tdb	1.19	_logger.write(Heartbeat__Monitor.this.toString(), Logger.WARNING, "Erronous Monitor.Heartbeat.checkPeriod value in configuration using default of " + checkPeriod + " seconds");
295	ajm	1.14	}
296
297	tdb	1.19	synchronized(Heartbeat__Monitor.this) {
298	ajm	1.14	// perform the checks (use HB hash, although they should be the same)
299			Iterator i = _hosts.keySet().iterator();
300			while(i.hasNext()) {
301			// get host
302			String source = (String) i.next();
303			// check it
304			boolean remove = analyseHB(source);
305	tdb	1.18	// remove it if it's passed a FINAL
306	ajm	1.14	if(remove) {
307			i.remove();
308			}
309			}
310			}
311
312			// wait a while
313			try {Thread.sleep(checkPeriod * 1000);} catch (InterruptedException e) {}
314			}
315			}
316	ajm	1.16
317	tdb	1.18	/**
318			* Analyses a given host's state, and if need be generates
319			* a relevant Alert. Note that it also checks if the last
320			* alert sent is FINAL, in which case it returns true to
321			* indicate removal of this host.
322			*
323			* @param source the host to check
324			* @return whether this host can be deleted
325			*/
326	ajm	1.16	private boolean analyseHB(String source) {
327			ConfigurationProxy cp = ConfigurationProxy.getInstance();
328			HeartbeatHolder hbHolder = (HeartbeatHolder) _hosts.get(source);
329	tdb	1.18	Register reg = hbHolder.getRegister();
330	ajm	1.16
331			// get host's HB interval (seconds)
332			// this should always exist, thus we set to 0
333			int hostHBinterval = 0;
334			try {
335			hostHBinterval = Integer.parseInt(cp.getProperty("Host."+source, "Host.TCPUpdateTime"));
336			} catch (PropertyNotFoundException e) {
337			hostHBinterval = 0;
338	tdb	1.19	_logger.write(Heartbeat__Monitor.this.toString(), Logger.WARNING, "TCPUpdateTime value unavailable using default of " + hostHBinterval + " seconds");
339	ajm	1.16	} catch (NumberFormatException e) {
340			hostHBinterval = 0;
341	tdb	1.19	_logger.write(Heartbeat__Monitor.this.toString(), Logger.WARNING, "Erronous TCPUpdateTime value in configuration using default of " + hostHBinterval + " seconds");
342	ajm	1.16	}
343
344			// get host's last HB time (seconds)
345			long lastHeartbeat = hbHolder.getLastHeartbeat();
346			// time since last heartbeat (seconds)
347			long timeSinceLastHB = (System.currentTimeMillis()/1000) - lastHeartbeat;
348			// time since (or until if negative) the expected heartbeat
349			long timeSinceExpectedHB = timeSinceLastHB - (long) hostHBinterval;
350
351			// best do a check in case the expected heartbeat is in the future
352			if(timeSinceExpectedHB < 0) {
353			timeSinceExpectedHB = 0;
354			}
355
356			// find out the threshold level we're at
357			int newThreshold = checkAttributeThreshold(timeSinceExpectedHB, reg);
358
359			// process the alert
360	ajm	1.17	Heartbeat__Monitor.this.processAlert(newThreshold, "Heartbeat", reg, source, String.valueOf(timeSinceExpectedHB));
361	ajm	1.16
362			if(reg.getLastAlertLevel() == Alert.alertFINAL) {
363			return true;
364			}
365			return false;
366			}
367	ajm	1.14	}
368	tdb	1.1	}