client/monitors/Heartbeat__Monitor.java

/* 
 * i-scream central monitoring system
 * 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.server.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 1.21 2001/11/26 12:56:33 tdb Exp $
 */
public class Heartbeat__Monitor extends MonitorSkeleton {

//---FINAL ATTRIBUTES---

    /**
     * The current CVS revision of this class
     */
    public final String REVISION = "$Revision: 1.21 $";
    
    /**
     * 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.server.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:	1.22
Committed:	Sat May 18 18:16:00 2002 UTC (22 years ago) by tdb
Branch:	MAIN
Changes since 1.21:	+22 -3 lines
Log Message:	i-scream is now licensed under the GPL. I've added the GPL headers to every source file, and put a full copy of the license in the appropriate places. I think I've covered everything. This is going to be a mad commit ;)
#	User	Rev	Content
1	tdb	1.22	/*
2			* i-scream central monitoring system
3			* Copyright (C) 2000-2002 i-scream
4			*
5			* This program is free software; you can redistribute it and/or
6			* modify it under the terms of the GNU General Public License
7			* as published by the Free Software Foundation; either version 2
8			* of the License, or (at your option) any later version.
9			*
10			* This program is distributed in the hope that it will be useful,
11			* but WITHOUT ANY WARRANTY; without even the implied warranty of
12			* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
13			* GNU General Public License for more details.
14			*
15			* You should have received a copy of the GNU General Public License
16			* along with this program; if not, write to the Free Software
17			* Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
18			*/
19
20	tdb	1.1	//---PACKAGE DECLARATION---
21	tdb	1.20	package uk.org.iscream.cms.server.client.monitors;
22	tdb	1.1
23			//---IMPORTS---
24			import java.util.HashMap;
25			import java.util.Iterator;
26	tdb	1.21	import java.util.StringTokenizer;
27	tdb	1.20	import uk.org.iscream.cms.server.client.*;
28			import uk.org.iscream.cms.server.core.*;
29			import uk.org.iscream.cms.server.util.*;
30			import uk.org.iscream.cms.server.componentmanager.*;
31	tdb	1.1
32			/**
33	tdb	1.18	* This Monitor watches heartbeats.
34			* It generates an alert when a heartbeat that is expected
35			* does not arrive. Unlike all the other monitors, this one
36			* is driven by an event not occuring, rather than an
37			* event occuring. This means it must be actively checking
38			* for missing heartbeat's, and thus has an extra inner class
39			* thread.
40	tdb	1.1	*
41	tdb	1.22	* @author $Author: tdb $
42			* @version $Id: Heartbeat__Monitor.java,v 1.21 2001/11/26 12:56:33 tdb Exp $
43	tdb	1.1	*/
44	ajm	1.14	public class Heartbeat__Monitor extends MonitorSkeleton {
45	tdb	1.1
46			//---FINAL ATTRIBUTES---
47
48			/**
49			* The current CVS revision of this class
50			*/
51	tdb	1.22	public final String REVISION = "$Revision: 1.21 $";
52	tdb	1.1
53	tdb	1.18	/**
54			* A description of this monitor
55			*/
56	tdb	1.1	public final String DESC = "Monitors Heartbeats.";
57
58	tdb	1.18	/**
59			* The default (used if not configured) period at
60			* which to check for old heartbeats. (in seconds)
61			*/
62	tdb	1.3	public final int DEFAULT_CHECK_PERIOD = 60;
63
64	tdb	1.1	//---STATIC METHODS---
65
66			//---CONSTRUCTORS---
67	tdb	1.18
68			/**
69			* Constructs a new Heartbeat monitor, and starts off
70			* the worker thread.
71			*/
72	tdb	1.2	public Heartbeat__Monitor() {
73	ajm	1.16	super();
74	tdb	1.21	createInitialHosts();
75	ajm	1.14	new HeartbeatWorker().start();
76	tdb	1.2	}
77
78	tdb	1.1	//---PUBLIC METHODS---
79
80	tdb	1.18	/**
81			* Analyse a packet of data. In this case, this will just
82			* register the fact that a heartbeat has arrived.
83			*
84			* @param packet The packet of data to analyse
85			*/
86	ajm	1.14	public void analysePacket(XMLPacket packet) {
87			String source = packet.getParam("packet.attributes.machine_name");
88			if (!_hosts.containsKey(source)) {
89	tdb	1.9	synchronized(this) {
90	tdb	1.18	_hosts.put(source, new HeartbeatHolder(new Register(source, _name)));
91	tdb	1.1	}
92			}
93	ajm	1.14	HeartbeatHolder lastHeartbeat = (HeartbeatHolder) _hosts.get(source);
94			lastHeartbeat.setLastHeartbeat(System.currentTimeMillis()/1000);
95	tdb	1.1	}
96
97			/**
98			* Overrides the {@link java.lang.Object#toString() Object.toString()}
99			* method to provide clean logging (every class should have this).
100			*
101	tdb	1.20	* This uses the uk.org.iscream.cms.server.util.NameFormat class
102	tdb	1.1	* to format the toString()
103			*
104			* @return the name of this class and its CVS revision
105			*/
106			public String toString() {
107			return FormatName.getName(
108			_name,
109			getClass().getName(),
110			REVISION);
111			}
112
113			/**
114			* return the String representation of what the monitor does
115			*/
116			public String getDescription(){
117			return DESC;
118			}
119
120			//---PRIVATE METHODS---
121
122	tdb	1.18	/**
123			* Checks whether the time since the last heartbeat
124			* is beyond the threshold(s).
125			*
126			* @param timeSinceLastHB a long time since the last heartbeat arrived
127			* @param reg the Register for this host
128			* @return the level which has been breached, if any
129			*/
130	tdb	1.2	private int checkAttributeThreshold(long timeSinceLastHB, Register reg) {
131	tdb	1.1	for(int thresholdLevel = Alert.thresholdLevels.length - 1; thresholdLevel >= 0; thresholdLevel--) {
132			if (reg.getThreshold(thresholdLevel) != -1.0) {
133	tdb	1.2	if (((long) reg.getThreshold(thresholdLevel)) < timeSinceLastHB) {
134	tdb	1.1	return thresholdLevel;
135			}
136			}
137			}
138	tdb	1.7	return Alert.thresholdNORMAL;
139	tdb	1.21	}
140
141			/**
142			* Gets an initial list of hosts from the config
143			* and adds a fake set of heartbeats for them.
144			* If the hosts don't respond within the timeout
145			* period an alert will be raised.
146			*
147			* The effect of this is to allow us to know about
148			* hosts which weren't on when we started up, and
149			* will thus never have generated a heartbeat - yet
150			* will still want to know they're not responding.
151			*/
152			private void createInitialHosts() {
153			// get the initial list of hosts from the config
154			String initialHosts = "";
155			try {
156			initialHosts = _cp.getProperty(_name, "Monitor.Heartbeat.initialHosts");
157			} catch (PropertyNotFoundException e) {
158			// just leave initialHosts empty
159			_logger.write(Heartbeat__Monitor.this.toString(), Logger.DEBUG, "No initial list of hosts set, defaulting to none.");
160			}
161
162			// parse through the initial hosts adding them
163			StringTokenizer st = new StringTokenizer(initialHosts, ";");
164			while (st.hasMoreTokens()) {
165			String source = st.nextToken();
166			// check if they already exist, don't want to add them twice
167			if (!_hosts.containsKey(source)) {
168			synchronized(this) {
169			_hosts.put(source, new HeartbeatHolder(new Register(source, _name)));
170			}
171			}
172			HeartbeatHolder lastHeartbeat = (HeartbeatHolder) _hosts.get(source);
173			// set a "fake" heartbeat
174			lastHeartbeat.setLastHeartbeat(System.currentTimeMillis()/1000);
175			}
176	tdb	1.1	}
177
178			//---ACCESSOR/MUTATOR METHODS---
179	tdb	1.18
180			/**
181			* Returns a reference to the Queue we're getting data
182			* from. This is specific to this monitor.
183			*
184			* @return a reference to a Queue to get data from
185			*/
186	ajm	1.14	protected Queue getQueue() {
187			return MonitorManager.getInstance().getHeartbeatQueue();
188			}
189
190	tdb	1.1	//---ATTRIBUTES---
191
192			/**
193			* This is the friendly identifier of the
194			* component this class is running in.
195			* eg, a Filter may be called "filter1",
196			* If this class does not have an owning
197			* component, a name from the configuration
198			* can be placed here. This name could also
199			* be changed to null for utility classes.
200			*/
201			private String _name = "Heartbeat";
202
203			/**
204			* A reference to the configuration proxy in use
205			*/
206			private ConfigurationProxy _cp = ConfigurationProxy.getInstance();
207	tdb	1.18
208			/**
209			* A HashMap of hosts, with associated HeartbeatHolder's.
210			*/
211	tdb	1.6	private HashMap _hosts = new HashMap();
212	tdb	1.18
213			/**
214			* A reference to the system logger.
215			*/
216	tdb	1.15	private Logger _logger = ReferenceManager.getInstance().getLogger();
217	tdb	1.1
218			//---STATIC ATTRIBUTES---
219
220			//---INNER CLASSES---
221	tdb	1.18
222			/**
223			* This inner class simply holding some information
224			* about a specific host.
225			*/
226	tdb	1.1	private class HeartbeatHolder {
227
228	tdb	1.18	/**
229			* Construct a new HeartbeatHolder.
230			*/
231			public HeartbeatHolder(Register register) {
232			_register = register;
233	tdb	1.6	}
234
235	tdb	1.18	/**
236			* Set the time of the last heartbeat
237			*/
238	tdb	1.2	public void setLastHeartbeat(long lastHeartbeat) {
239	tdb	1.1	_lastHeartbeat = lastHeartbeat;
240			}
241
242	tdb	1.18	/**
243			* Get the time of the last heartbeat
244			*/
245	tdb	1.2	public long getLastHeartbeat() {
246	tdb	1.1	return _lastHeartbeat;
247			}
248
249	tdb	1.18	/**
250			* Get the Register
251			*/
252			public Register getRegister() {
253			return _register;
254	tdb	1.6	}
255
256	tdb	1.18	/**
257			* last heartbeat time
258			*/
259	tdb	1.2	private long _lastHeartbeat;
260	tdb	1.18
261			/**
262			* register ref
263			*/
264			private Register _register;
265	ajm	1.14	}
266
267	tdb	1.18	/**
268			* This worker thread just checks all the hosts and then
269			* waits a period of time before doing it again. It sends
270			* Alerts as required.
271			*/
272	ajm	1.14	private class HeartbeatWorker extends Thread {
273
274	tdb	1.18	/**
275			* The main run method of this worker thread. It simply
276			* checks through all the hosts it has stored, running
277			* the analyseHB method on each. It then removes any
278			* that have passed a FINAL, and waits a (configured)
279			* length of time before doing it again.
280			*/
281	ajm	1.14	public void run() {
282			ConfigurationProxy cp = ConfigurationProxy.getInstance();
283			while(true) {
284			// this cycle period of this monitor's checks
285			int checkPeriod = 0;
286			try {
287			checkPeriod = Integer.parseInt(cp.getProperty(_name, "Monitor.Heartbeat.checkPeriod"));
288			} catch (PropertyNotFoundException e) {
289			checkPeriod = DEFAULT_CHECK_PERIOD;
290	tdb	1.19	_logger.write(Heartbeat__Monitor.this.toString(), Logger.WARNING, "Monitor.Heartbeat.checkPeriod value unavailable using default of " + checkPeriod + " seconds");
291	ajm	1.14	} catch (NumberFormatException e) {
292			checkPeriod = DEFAULT_CHECK_PERIOD;
293	tdb	1.19	_logger.write(Heartbeat__Monitor.this.toString(), Logger.WARNING, "Erronous Monitor.Heartbeat.checkPeriod value in configuration using default of " + checkPeriod + " seconds");
294	ajm	1.14	}
295
296	tdb	1.19	synchronized(Heartbeat__Monitor.this) {
297	ajm	1.14	// perform the checks (use HB hash, although they should be the same)
298			Iterator i = _hosts.keySet().iterator();
299			while(i.hasNext()) {
300			// get host
301			String source = (String) i.next();
302			// check it
303			boolean remove = analyseHB(source);
304	tdb	1.18	// remove it if it's passed a FINAL
305	ajm	1.14	if(remove) {
306			i.remove();
307			}
308			}
309			}
310
311			// wait a while
312			try {Thread.sleep(checkPeriod * 1000);} catch (InterruptedException e) {}
313			}
314			}
315	ajm	1.16
316	tdb	1.18	/**
317			* Analyses a given host's state, and if need be generates
318			* a relevant Alert. Note that it also checks if the last
319			* alert sent is FINAL, in which case it returns true to
320			* indicate removal of this host.
321			*
322			* @param source the host to check
323			* @return whether this host can be deleted
324			*/
325	ajm	1.16	private boolean analyseHB(String source) {
326			ConfigurationProxy cp = ConfigurationProxy.getInstance();
327			HeartbeatHolder hbHolder = (HeartbeatHolder) _hosts.get(source);
328	tdb	1.18	Register reg = hbHolder.getRegister();
329	ajm	1.16
330			// get host's HB interval (seconds)
331			// this should always exist, thus we set to 0
332			int hostHBinterval = 0;
333			try {
334			hostHBinterval = Integer.parseInt(cp.getProperty("Host."+source, "Host.TCPUpdateTime"));
335			} catch (PropertyNotFoundException e) {
336			hostHBinterval = 0;
337	tdb	1.19	_logger.write(Heartbeat__Monitor.this.toString(), Logger.WARNING, "TCPUpdateTime value unavailable using default of " + hostHBinterval + " seconds");
338	ajm	1.16	} catch (NumberFormatException e) {
339			hostHBinterval = 0;
340	tdb	1.19	_logger.write(Heartbeat__Monitor.this.toString(), Logger.WARNING, "Erronous TCPUpdateTime value in configuration using default of " + hostHBinterval + " seconds");
341	ajm	1.16	}
342
343			// get host's last HB time (seconds)
344			long lastHeartbeat = hbHolder.getLastHeartbeat();
345			// time since last heartbeat (seconds)
346			long timeSinceLastHB = (System.currentTimeMillis()/1000) - lastHeartbeat;
347			// time since (or until if negative) the expected heartbeat
348			long timeSinceExpectedHB = timeSinceLastHB - (long) hostHBinterval;
349
350			// best do a check in case the expected heartbeat is in the future
351			if(timeSinceExpectedHB < 0) {
352			timeSinceExpectedHB = 0;
353			}
354
355			// find out the threshold level we're at
356			int newThreshold = checkAttributeThreshold(timeSinceExpectedHB, reg);
357
358			// process the alert
359	ajm	1.17	Heartbeat__Monitor.this.processAlert(newThreshold, "Heartbeat", reg, source, String.valueOf(timeSinceExpectedHB));
360	ajm	1.16
361			if(reg.getLastAlertLevel() == Alert.alertFINAL) {
362			return true;
363			}
364			return false;
365			}
366	ajm	1.14	}
367	tdb	1.1	}