org.spf4j.stackmonitor

Class Sampler

java.lang.Object

org.spf4j.stackmonitor.Sampler

@ThreadSafe
public final class Sampler
extends Object

Utility to sample stack traces. Stack traces can be persisted for later analysis. please read http://sape.inf.usi.ch/sites/default/files/publication/pldi10.pdf pure java stack sampling will probably have safepoint bias.

Author:

zoly

Field Summary

Fields

Modifier and Type	Field and Description
static String	DEFAULT_SS_DUMP_FILE_NAME_PREFIX
static String	DEFAULT_SS_DUMP_FOLDER

Constructor Summary

Constructors

Constructor and Description
Sampler()
Sampler(int sampleTimeMillis)
Sampler(int sampleTimeMillis, int dumpTimeMillis)
Sampler(int sampleTimeMillis, int dumpTimeMillis, SamplerSupplier collector)
Sampler(int sampleTimeMillis, int dumpTimeMillis, SamplerSupplier collector, File dumpFolder, String dumpFilePrefix)
Sampler(int sampleTimeMillis, int dumpTimeMillis, SamplerSupplier collector, String dumpFolder, String dumpFilePrefix)
Sampler(int sampleTimeMillis, SamplerSupplier collector)
Sampler(SamplerSupplier collector)

Method Summary

Modifier and Type	Method and Description
void	clear()
void	dispose()
File	dumpToFile()
File	dumpToFile(File pfile)
File	dumpToFile(String id) Dumps the sampled stacks to file.
int	getDumpTimeMillis()
static Sampler	getSampler(int sampleTimeMillis, int dumpTimeMillis, File dumpFolder, String dumpFilePrefix)
static Sampler	getSampler(int sampleTimeMillis, int dumpTimeMillis, SamplerSupplier collector, File dumpFolder, String dumpFilePrefix)
int	getSampleTimeMillis()
Map<String,SampleNode>	getStackCollections()
Map<String,SampleNode>	getStackCollectionsAndReset()
boolean	isStopped()
void	registerJmx()
void	setDumpTimeMillis(int dumpTimeMillis)
void	setSampleTimeMillis(int sampleTimeMillis)
void	start()
void	stop()
String	toString()

Methods inherited from class java.lang.Object

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

Field Detail

DEFAULT_SS_DUMP_FOLDER

public static final String DEFAULT_SS_DUMP_FOLDER

DEFAULT_SS_DUMP_FILE_NAME_PREFIX

public static final String DEFAULT_SS_DUMP_FILE_NAME_PREFIX

Constructor Detail

Sampler

public Sampler()

Sampler

public Sampler(int sampleTimeMillis)

Sampler

public Sampler(int sampleTimeMillis,
               SamplerSupplier collector)

Sampler

public Sampler(SamplerSupplier collector)

Sampler

public Sampler(int sampleTimeMillis,
               int dumpTimeMillis)

Sampler

public Sampler(int sampleTimeMillis,
               int dumpTimeMillis,
               SamplerSupplier collector)

Sampler

public Sampler(int sampleTimeMillis,
               int dumpTimeMillis,
               SamplerSupplier collector,
               String dumpFolder,
               String dumpFilePrefix)

Sampler

public Sampler(int sampleTimeMillis,
               int dumpTimeMillis,
               SamplerSupplier collector,
               File dumpFolder,
               String dumpFilePrefix)

Method Detail

toString

public String toString()

Overrides:

toString in class Object

getSampler

public static Sampler getSampler(int sampleTimeMillis,
                                 int dumpTimeMillis,
                                 File dumpFolder,
                                 String dumpFilePrefix)
                          throws InterruptedException

Throws:

InterruptedException

getSampler

public static Sampler getSampler(int sampleTimeMillis,
                                 int dumpTimeMillis,
                                 SamplerSupplier collector,
                                 File dumpFolder,
                                 String dumpFilePrefix)
                          throws InterruptedException

Throws:

InterruptedException

registerJmx

public void registerJmx()

start

public void start()

dumpToFile

@Nullable
public File dumpToFile()
                          throws IOException

Throws:

IOException

dumpToFile

@Nullable
public File dumpToFile(@Nullable
                                 String id)
                          throws IOException

Dumps the sampled stacks to file. the collected samples are reset

Parameters:

id - - id will be added to file name returns the name of the file.

Returns:

- the file name where the data was persisted or null if there was no data to persist.

Throws:

IOException - - io issues while persisting data.

dumpToFile

@Nullable
public File dumpToFile(@Nonnull
                                 File pfile)
                          throws IOException

Throws:

IOException

stop

public void stop()
          throws InterruptedException

Throws:

InterruptedException

getSampleTimeMillis

public int getSampleTimeMillis()

setSampleTimeMillis

public void setSampleTimeMillis(int sampleTimeMillis)

isStopped

public boolean isStopped()

clear

public void clear()

getStackCollectionsAndReset

public Map<String,SampleNode> getStackCollectionsAndReset()

getStackCollections

public Map<String,SampleNode> getStackCollections()

dispose

@PreDestroy
public void dispose()
                         throws InterruptedException

Throws:

InterruptedException

getDumpTimeMillis

public int getDumpTimeMillis()

setDumpTimeMillis

public void setDumpTimeMillis(int dumpTimeMillis)