org.codehaus.activemq.journal
Class JournalStatsFilter

java.lang.Object
  org.codehaus.activemq.journal.JournalStatsFilter

All Implemented Interfaces:

Journal

public class JournalStatsFilter

extends Object

implements Journal

A Journal filter that captures performance statistics of the filtered Journal.

Version:

$Revision: 1.2 $

Constructor Summary

JournalStatsFilter(Journal next)
Creates a JournalStatsFilter that captures performance information of next.

Method Summary

void	close() Close the Journal.
void	dump(IndentPrinter out) Writes the gathered statistics to the out object.
JournalStatsFilter	enableDetailedStats(boolean detailedStats)
double	getAvgSyncedLatencyMs() Gets the average sync write latency in ms.
double	getAvgUnSyncedLatencyMs() Gets the average non sync write latency in ms.
RecordLocation	getMark() Obtains the mark that was set in the Journal.
RecordLocation	getNextRecordLocation(RecordLocation lastLocation) Allows you to get the next RecordLocation after the location that is in the journal.
double	getThroughputKps() Gets the average throughput in k/s.
double	getThroughputRps() Gets the average throughput in records/s.
double	getWritesPerSecond() Gets the average number of writes done per second
byte[]	read(RecordLocation location) Reads a previously written record from the journal.
void	reset() Resets the stats sample.
void	setJournalEventListener(JournalEventListener eventListener) Registers a JournalEventListener that will receive notifications from the Journal.
void	setMark(RecordLocation recordLocator, boolean force) Informs the journal that all the journal space up to the location is no longer needed and can be reclaimed for reuse.
String	toString() Dumps the stats to a String.
RecordLocation	write(byte[] data, boolean sync) Writes a byte array record to the journal.

Methods inherited from class java.lang.Object

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

Constructor Detail

JournalStatsFilter

public JournalStatsFilter(Journal next)

Creates a JournalStatsFilter that captures performance information of next.

Parameters:

next -

Method Detail

write

public RecordLocation write(byte[] data,
                            boolean sync)
                     throws IOException

Description copied from interface: Journal

Writes a byte array record to the journal. If sync is true, then this call blocks until the data has landed on the physical disk. Otherwise, this call returns imeadiatly.

Specified by:

write in interface Journal

Parameters:

data - - the data to be written to disk.

sync - - If this call should block until the data lands on disk.

Returns:

RecordLocation the location where the data will be written to on disk.

Throws:

IOException - if the write failed.

See Also:

Journal.write(byte[], boolean)

read

public byte[] read(RecordLocation location)
            throws InvalidRecordLocationException,
                   IOException

Description copied from interface: Journal

Reads a previously written record from the journal.

Specified by:

read in interface Journal

Parameters:

location - is where to read the record from.

Returns:

the data previously written at the location.

Throws:

IOException - if the record could not be read.

InvalidRecordLocationException - if location parameter is out of range. It cannot be a location that is before the current mark.

See Also:

Journal.read(org.codehaus.activemq.journal.RecordLocation)

setMark

public void setMark(RecordLocation recordLocator,
                    boolean force)
             throws InvalidRecordLocationException,
                    IOException

Description copied from interface: Journal

Informs the journal that all the journal space up to the location is no longer needed and can be reclaimed for reuse.

Specified by:

setMark in interface Journal

Parameters:

recordLocator - the location of the record to mark. All record locations before the marked location will no longger be vaild.

force - if this call should block until the mark is set on the journal.

Throws:

InvalidRecordLocationException - if location parameter is out of range. It cannot be a location that is before the current mark.

IOException - if the record could not be read.

See Also:

Journal.setMark(org.codehaus.activemq.journal.RecordLocation, boolean)

getMark

public RecordLocation getMark()

Description copied from interface: Journal

Obtains the mark that was set in the Journal.

Specified by:

getMark in interface Journal

Returns:

the mark that was set in the Journal.

See Also:

Journal.getMark()

close

public void close()
           throws IOException

Description copied from interface: Journal

Close the Journal. This is blocking operation that waits for any pending put opperations to be forced to disk. Once the Journal is closed, all other methods of the journal should throw IllegalStateException.

Specified by:

close in interface Journal

Throws:

IOException - if an error occurs while the journal is being closed.

See Also:

Journal.close()

setJournalEventListener

public void setJournalEventListener(JournalEventListener eventListener)

Description copied from interface: Journal

Registers a JournalEventListener that will receive notifications from the Journal.

Specified by:

setJournalEventListener in interface Journal

Parameters:

eventListener - object that will receive journal events.

See Also:

Journal.setJournalEventListener(org.codehaus.activemq.journal.JournalEventListener)

getNextRecordLocation

public RecordLocation getNextRecordLocation(RecordLocation lastLocation)
                                     throws IOException,
                                            InvalidRecordLocationException

Description copied from interface: Journal

Allows you to get the next RecordLocation after the location that is in the journal.

Specified by:

getNextRecordLocation in interface Journal

Parameters:

lastLocation - the reference location the is used to find the next location. To get the oldest location available in the journal, location should be set to null.

Returns:

the next record location

Throws:

InvalidRecordLocationException - if location parameter is out of range. It cannot be a location that is before the current mark.

IOException

See Also:

Journal.getNextRecordLocation(org.codehaus.activemq.journal.RecordLocation)

dump

public void dump(IndentPrinter out)

Writes the gathered statistics to the out object.

Parameters:

out -

toString

public String toString()

Dumps the stats to a String.

See Also:

Object.toString()

enableDetailedStats

public JournalStatsFilter enableDetailedStats(boolean detailedStats)

Parameters:

detailedStats - true if details stats should be displayed by toString() and dump

Returns:

getThroughputKps

public double getThroughputKps()

Gets the average throughput in k/s.

Returns:

the average throughput in k/s.

getThroughputRps

public double getThroughputRps()

Gets the average throughput in records/s.

Returns:

the average throughput in records/s.

getWritesPerSecond

public double getWritesPerSecond()

Gets the average number of writes done per second

Returns:

the average number of writes in w/s.

getAvgSyncedLatencyMs

public double getAvgSyncedLatencyMs()

Gets the average sync write latency in ms.

Returns:

the average sync write latency in ms.

getAvgUnSyncedLatencyMs

public double getAvgUnSyncedLatencyMs()

Gets the average non sync write latency in ms.

Returns:

the average non sync write latency in ms.

reset

public void reset()

Resets the stats sample.