org.qbroker.monitor

Class FileMonitor

java.lang.Object

org.qbroker.monitor.Monitor

org.qbroker.monitor.FileMonitor

All Implemented Interfaces:

MonitorAction, MonitorReport

public class FileMonitor
extends Monitor

FileMonitor.java monitors a given file on its last modified time and/or size

Use FileMonitor to get the last modified time and/or size of a given file. It is assumed that the file exists and is readable all times. FileMonitor can monitor a remote file as long as the protocol is defined. In case of FTP protocol, FileMonitor supports two implementations. One is the traditional FTP with SetPassiveMode set to true or false, or without any datalink via using two new cmd of MDTZ and SIZE.

You can use FileMonitor to monitor when the file has been updated. If not, how late it is. In case of very late, FileMonitor sends alerts.

FileMonitor also supports mtime correlations and size correlations between two files. In this case, there are two files involved. One is the reference file. The other is the target file to be monitored. The reference file controls the correlation process. Whenever the reference file is updated or modified, FileMonitor adjusts its timer and correlates this change with the target file. If the target file has been updated accordingly, the FileMonitor treats it OK. Otherwise, it will send alerts according to the predefined tolerance on the lateness of the target file being updated.

In order to configure FileMonitor to do time correlations, you have to specify a Map named as reference in its property hash. The reference hash table contains most of the properties required by a FileMonitor object, such as filename, name, etc. The tolerance of the lateness will be controlled by the threshold parameters. In fact, FileMonitor will create a separate instance for the reference file. The method of performAction() will actually do the time correlations between two files.

In case of the size correlations, you must specify the triggerSize in the property hashmap. The triggerSize is zero or any positive number that defines two different states. One is the state that the file size is less than the triggerSize. The other is the opposite. In case state of the reference file changes, FileMonitor will check the state of the target file. If both files are in the same states, FileMonitor thinks it OK. Otherwise, FileMonitor will send alerts according to the predefined tolerance on the lateness of the target file keeping its state in sync.

In case of monitoring timestamp on a remote box, there is an issue with its Daylight Time on its TimeZone. For example of EST, the timestamp of Oct. 31 2004, 01:30:00 EST is 3600 seconds later than Oct. 31 2004, 01:30:00 EDT. The same time strings give two different Unix timestamps. If there is no TimeZone info available in the time string, you have to guess its real value. The hack implemented here is based on an assumption that the remote timestamp is close to the currentTime of the local box. Therefore, if the difference between the remote time and the currentTime is large than the half DST_OFFSET of the remote TimeZone, the remote time will be adjusted with the DST_OFFSET. Otherwise, no adjustment.

Author:

yannanlu@yahoo.com

Field Summary

Fields inherited from class org.qbroker.monitor.Monitor

actionCount, actionGroup, aPatternGroup, cachedSkip, category, dependencyGroup, description, disabledWithReport, disableMode, exceptionCount, exceptionTolerance, FILE_SEPARATOR, formatText, keyList, maxPage, maxRetry, name, normalStep, pm, previousStatus, repeatPeriod, report, reportMode, reportName, resolution, serialNumber, site, skip, statsLogger, statusOffset, statusText, step, template, timeFormat, timeTemplate, tolerance, type, xPatternGroup

Fields inherited from interface org.qbroker.monitor.MonitorReport

DISABLED, EXCEPTION, NOSKIP, REPORT_CACHED, REPORT_CLUSTER, REPORT_FINAL, REPORT_FLOW, REPORT_LOCAL, REPORT_NODE, REPORT_NONE, REPORT_SHARED, SKIPPED

Constructor Summary

Constructors

Constructor and Description
FileMonitor(java.util.Map props)

Method Summary

Modifier and Type	Method and Description
java.util.Map<java.lang.String,java.lang.Object>	checkpoint() returns the checkpoint Map for the action
void	destroy() closes and releases all opened resources
protected void	finalize()
java.util.Map<java.lang.String,java.lang.Object>	generateReport(long currentTime) generates a report on a monitored entity and returns it as a Map.
Event	performAction(int status, long currentTime, java.util.Map<java.lang.String,java.lang.Object> latest) examines the report on the monitored entity and reacts to it as an action
void	restoreFromCheckpoint(java.util.Map<java.lang.String,java.lang.Object> chkpt) restores the state of the action from the checkpoint Map

Methods inherited from class org.qbroker.monitor.Monitor

getName, getReportKeys, getReportMode, getReportName, getSkippingStatus, initTimeTemplate, updateContent

Methods inherited from class java.lang.Object

clone, equals, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

FileMonitor

public FileMonitor(java.util.Map props)

Method Detail

generateReport

public java.util.Map<java.lang.String,java.lang.Object> generateReport(long currentTime)
                                                                throws java.io.IOException

Description copied from interface: MonitorReport

generates a report on a monitored entity and returns it as a Map. The report Map will be passed to the associated MonitorAction as an opaque object. The action object is supposed to know how to retrieve the information from the report Map.

Specified by:

generateReport in interface MonitorReport

Specified by:

generateReport in class Monitor

Throws:

java.io.IOException

performAction

public Event performAction(int status,
                           long currentTime,
                           java.util.Map<java.lang.String,java.lang.Object> latest)

Description copied from interface: MonitorAction

examines the report on the monitored entity and reacts to it as an action

Specified by:

performAction in interface MonitorAction

Specified by:

performAction in class Monitor

checkpoint

public java.util.Map<java.lang.String,java.lang.Object> checkpoint()

Description copied from interface: MonitorAction

returns the checkpoint Map for the action

Specified by:

checkpoint in interface MonitorAction

Overrides:

checkpoint in class Monitor

restoreFromCheckpoint

public void restoreFromCheckpoint(java.util.Map<java.lang.String,java.lang.Object> chkpt)

Description copied from interface: MonitorAction

restores the state of the action from the checkpoint Map

Specified by:

restoreFromCheckpoint in interface MonitorAction

Overrides:

restoreFromCheckpoint in class Monitor

destroy

public void destroy()

Description copied from interface: MonitorReport

closes and releases all opened resources

Specified by:

destroy in interface MonitorReport

Overrides:

destroy in class Monitor

finalize

protected void finalize()

Overrides:

finalize in class Monitor