org.netbeans.modules.sampler

Class Sampler

java.lang.Object

org.netbeans.modules.sampler.Sampler

public abstract class Sampler
extends Object

Sampler class provides API for self-sampling of NetBeans platform application. The self-sampling should be used for diagnostic purposes and should help NetBeans platform developers with solving CPU related performance problems. Sampled data are stored in NPSS file, which can be opened by NetBeans Profiler or Java VisualVM for later analysis of sampled data.

Method Summary

Modifier and Type	Method and Description
void	cancel() Cancels the self-sampling.
static Sampler	createManualSampler(String name) Factory method for creating Sampler suitable for manual or user invoked scanning.
static Sampler	createSampler(String name) Factory method for creating Sampler suitable for automatic reporting of the slow operation (i.e.
void	start() Start self-sampling.
void	stop() Stop the self-sampling, save and open gathered data.
void	stopAndWriteTo(DataOutputStream dos) Stop the self-sampling started by Sampler.start() method and writes the data to DataOutputStream.

Methods inherited from class java.lang.Object

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

Method Detail

createSampler

@CheckForNull
public static Sampler createSampler(@NonNull
                                                  String name)

Factory method for creating Sampler suitable for automatic reporting of the slow operation (i.e. AWT blocked for some time). This method can return null if the sampled application is in nonstandard mode which will produce unrealistic data - for example application is running under debugger or profiler. It can return null if it is running on some exotic variant of JDK, where sampling is not supported.

Parameters:

name - which identifies the sampler thread

Returns:

instance of the Sampler or null if application is in nonstandard mode or sampling is not supported.

createManualSampler

@CheckForNull
public static Sampler createManualSampler(@NonNull
                                                        String name)

Factory method for creating Sampler suitable for manual or user invoked scanning. This method can return null if it is running on some exotic variant of JDK, where sampling is not supported.

Parameters:

name - which identifies the sampler thread

Returns:

instance of the Sampler or null if sampling is not supported.

start

public final void start()

Start self-sampling. This method starts timer identified by name for actual sampling and returns immediately.

cancel

public final void cancel()

Cancels the self-sampling. All sampled data are discarded.

stopAndWriteTo

public final void stopAndWriteTo(@NonNull
                                 DataOutputStream dos)

Stop the self-sampling started by Sampler.start() method and writes the data to DataOutputStream. If the internal sampling logic detects that the data are distorted for example due to heavy system I/O, collected samples are discarded and nothing is written to DataOutputStream.
This method can take a long time and should not be invoked from EDT.

Parameters:

dos - DataOutputStream where sampled data is written to.

stop

public final void stop()

Stop the self-sampling, save and open gathered data. If there is no sampled data, this method does nothing and returns immediately.
This method can take a long time and should not be invoked from EDT.