org.xmlBlaster.contrib.dbwatcher.detector
Class TimestampChangeDetector

java.lang.Object
  org.xmlBlaster.contrib.dbwatcher.detector.TimestampChangeDetector

All Implemented Interfaces:

I_ChangeDetector, TimestampChangeDetectorMBean

public class TimestampChangeDetector

extends java.lang.Object

implements I_ChangeDetector, TimestampChangeDetectorMBean

Check the database and compare the change timestamp of a table to the previous one.

Configuration

• changeDetector.detectStatement the SQL statement which detects that a change has occurred, for example SELECT MAX(TO_CHAR(ts, 'YYYY-MM-DD HH24:MI:SSXFF')) FROM TEST_TS
• changeDetector.timestampColNum is set to 1 and specifies the column number where the above changeDetector.detectStatement delivers the max result. Usually you don't need to change this.
• db.queryMeatStatement is executed when a change was detected, it collects the wanted data to send as a message, for example SELECT * FROM TEST_POLL WHERE TO_CHAR(TS, 'YYYY-MM-DD HH24:MI:SSXFF') > '${oldTimestamp}' ORDER BY CAR. It should be order by the changeDetector.groupColName value (if such is given).
• changeDetector.groupColName in the above example ICAO_ID, the SELECT must be sorted after this column and must list it. All distinct ICAO_ID values trigger an own publish event. If not configured, this plugin triggers on change exactly one publish event.
• changeDetector.ignoreExistingDataOnStartup defaults to false, like this all SQL data in the observed table are delivered on DbWatcher startup. If you set this to true only the future changes are detected after a new xmlBlaster restart.

Limitations

The nature of this plugin is based on a timestamp comparison, as such it does not detect DELETE changes of database rows, as this will not create a new timestamp. All other commands (CREATE, INSERT, UPDATE) will touch the timestamp and are therefor detected. Additionally a DROP is detected.

DB statement	Reported change	Comment
CREATE	CREATE	-
INSERT	UPDATE	SQL INSERT statement are reported as UPDATE
UPDATE	UPDATE	-
DELETE	-	Is not detected
DROP	DROP	see mom.eraseOnDrop configuration

Note that the previous timestamp value is hold in RAM only, after plugin restart it is lost and a complete set of data is send again.

Author:

Marcel Ruff, Michele Laghi

Field Summary

protected java.lang.String	changeCommand
protected java.lang.String	changeDetectStatement
protected I_ChangeListener	changeListener
protected I_DataConverter	dataConverter
protected I_DbPool	dbPool
protected java.lang.String	groupColName
protected boolean	ignoreExistingDataOnStartup
protected I_Info	info
protected java.lang.String	newTimestamp
protected java.lang.String	oldTimestamp
protected boolean	poolOwner
protected java.lang.String	queryMeatStatement
protected boolean	tableExists
protected int	timestampColNum
protected boolean	useGroupCol

Constructor Summary

TimestampChangeDetector()

Method Summary

void	activateDetection()
int	checkAgain(java.util.Map attrMap) Check the observed data for changes.
java.lang.String	getChangeCommand()
java.lang.String	getChangeDetectStatement()
java.lang.String	getGroupColName()
java.lang.String	getNewTimestamp()
java.lang.String	getOldTimestamp()
java.lang.String	getQueryMeatStatement()
int	getTimestampColNum()
void	init(I_Info info, I_ChangeListener changeListener, I_DataConverter dataConverter) Needs to be called after construction.
boolean	isIgnoreDetection()
boolean	isIgnoreExistingDataOnStartup()
boolean	isPoolOwner()
boolean	isTableExists()
boolean	isUseGroupCol()
static java.lang.String	modifyMinStrIfDate(java.lang.String in, long time)
java.lang.String	modifyMinStrIfDateWithPersistence(java.lang.String in, long time) Modifies a string if it contains the special token '${currentDate}'.
void	setChangeCommand(java.lang.String changeCommand)
void	setChangeDetectStatement(java.lang.String changeDetectStatement)
void	setGroupColName(java.lang.String groupColName)
void	setOldTimestamp(java.lang.String oldTimestamp)
void	setPoolOwner(boolean poolOwner)
void	setQueryMeatStatement(java.lang.String queryMeatStatement)
void	setTimestampColNum(int timestampColNum)
void	setUseGroupCol(boolean useGroupCol)
void	shutdown() Cleanup resources.
void	stopDetection()

Methods inherited from class java.lang.Object

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

Field Detail

info

protected I_Info info

changeListener

protected I_ChangeListener changeListener

dataConverter

protected I_DataConverter dataConverter

dbPool

protected I_DbPool dbPool

poolOwner

protected boolean poolOwner

changeDetectStatement

protected java.lang.String changeDetectStatement

timestampColNum

protected int timestampColNum

groupColName

protected java.lang.String groupColName

useGroupCol

protected boolean useGroupCol

tableExists

protected boolean tableExists

ignoreExistingDataOnStartup

protected boolean ignoreExistingDataOnStartup

changeCommand

protected java.lang.String changeCommand

oldTimestamp

protected java.lang.String oldTimestamp

newTimestamp

protected java.lang.String newTimestamp

queryMeatStatement

protected java.lang.String queryMeatStatement

Constructor Detail

TimestampChangeDetector

public TimestampChangeDetector()

Method Detail

modifyMinStrIfDateWithPersistence

public java.lang.String modifyMinStrIfDateWithPersistence(java.lang.String in,
                                                          long time)
                                                   throws java.lang.Exception

Modifies a string if it contains the special token '${currentDate}'. The correct syntax would be : ${currentDate}=yyyy-MM-dd HH:mm:ss.0 Note that spaces after the equality sign count. If you only specify ${currentDate} without equality Sign, then the current time returned as System.getCurrentTime() is returned. This method is made public for testing.

Parameters:

in -

Returns:

Throws:

java.lang.Exception

modifyMinStrIfDate

public static java.lang.String modifyMinStrIfDate(java.lang.String in,
                                                  long time)
                                           throws java.lang.Exception

Throws:

java.lang.Exception

init

public void init(I_Info info,
                 I_ChangeListener changeListener,
                 I_DataConverter dataConverter)
          throws java.lang.Exception

Description copied from interface: I_ChangeDetector

Needs to be called after construction.

Specified by:

init in interface I_ChangeDetector

Parameters:

info -

changeListener -

dataConverter -

Throws:

java.lang.Exception

See Also:

I_ChangeDetector.init(org.xmlBlaster.contrib.I_Info, org.xmlBlaster.contrib.dbwatcher.I_ChangeListener, org.xmlBlaster.contrib.dbwatcher.convert.I_DataConverter)

checkAgain

public int checkAgain(java.util.Map attrMap)
               throws java.lang.Exception

Check the observed data for changes.

Specified by:

checkAgain in interface I_ChangeDetector

Parameters:

attrMap - Currently "oldTimestamp" can be passed to force a specific scan

Returns:

true if the observed data has changed

Throws:

java.lang.Exception - Can be of any type

See Also:

I_ChangeDetector.checkAgain(java.util.Map)

shutdown

public void shutdown()
              throws java.lang.Exception

Description copied from interface: I_ChangeDetector

Cleanup resources.

Specified by:

shutdown in interface I_ChangeDetector

Throws:

java.lang.Exception - Can be of any type

See Also:

I_ChangeDetector.shutdown()

getChangeCommand

public java.lang.String getChangeCommand()

Specified by:

getChangeCommand in interface TimestampChangeDetectorMBean

getChangeDetectStatement

public java.lang.String getChangeDetectStatement()

Specified by:

getChangeDetectStatement in interface TimestampChangeDetectorMBean

getGroupColName

public java.lang.String getGroupColName()

Specified by:

getGroupColName in interface TimestampChangeDetectorMBean

getNewTimestamp

public java.lang.String getNewTimestamp()

Specified by:

getNewTimestamp in interface TimestampChangeDetectorMBean

getOldTimestamp

public java.lang.String getOldTimestamp()

Specified by:

getOldTimestamp in interface TimestampChangeDetectorMBean

getQueryMeatStatement

public java.lang.String getQueryMeatStatement()

Specified by:

getQueryMeatStatement in interface TimestampChangeDetectorMBean

getTimestampColNum

public int getTimestampColNum()

Specified by:

getTimestampColNum in interface TimestampChangeDetectorMBean

isIgnoreExistingDataOnStartup

public boolean isIgnoreExistingDataOnStartup()

Specified by:

isIgnoreExistingDataOnStartup in interface TimestampChangeDetectorMBean

isPoolOwner

public boolean isPoolOwner()

Specified by:

isPoolOwner in interface TimestampChangeDetectorMBean

isTableExists

public boolean isTableExists()

Specified by:

isTableExists in interface TimestampChangeDetectorMBean

isUseGroupCol

public boolean isUseGroupCol()

Specified by:

isUseGroupCol in interface TimestampChangeDetectorMBean

setChangeCommand

public void setChangeCommand(java.lang.String changeCommand)

Specified by:

setChangeCommand in interface TimestampChangeDetectorMBean

setChangeDetectStatement

public void setChangeDetectStatement(java.lang.String changeDetectStatement)

Specified by:

setChangeDetectStatement in interface TimestampChangeDetectorMBean

setGroupColName

public void setGroupColName(java.lang.String groupColName)

Specified by:

setGroupColName in interface TimestampChangeDetectorMBean

setOldTimestamp

public void setOldTimestamp(java.lang.String oldTimestamp)

Specified by:

setOldTimestamp in interface TimestampChangeDetectorMBean

setPoolOwner

public void setPoolOwner(boolean poolOwner)

Specified by:

setPoolOwner in interface TimestampChangeDetectorMBean

setQueryMeatStatement

public void setQueryMeatStatement(java.lang.String queryMeatStatement)

Specified by:

setQueryMeatStatement in interface TimestampChangeDetectorMBean

setTimestampColNum

public void setTimestampColNum(int timestampColNum)

Specified by:

setTimestampColNum in interface TimestampChangeDetectorMBean

setUseGroupCol

public void setUseGroupCol(boolean useGroupCol)

Specified by:

setUseGroupCol in interface TimestampChangeDetectorMBean

stopDetection

public void stopDetection()

Specified by:

stopDetection in interface TimestampChangeDetectorMBean

activateDetection

public void activateDetection()

Specified by:

activateDetection in interface TimestampChangeDetectorMBean

isIgnoreDetection

public boolean isIgnoreDetection()

Specified by:

isIgnoreDetection in interface TimestampChangeDetectorMBean