Package io.perfmark.java9

Class SecretGenerator.VarHandleGenerator

java.lang.Object

io.perfmark.impl.Generator

io.perfmark.java9.SecretGenerator.VarHandleGenerator

Enclosing class:

SecretGenerator

public static final class SecretGenerator.VarHandleGenerator
extends Generator

This class let's PerfMark have fairly low overhead detection if it is enabled, with reasonable time between enabled and other threads noticing. Since this uses Java 9 APIs, it may not be available.

Field Summary

Fields

Modifier and Type	Field	Description
private long	gen
private static final VarHandle	GEN

Fields inherited from class io.perfmark.impl.Generator

FAILURE, GEN_OFFSET

Constructor Summary

Constructors

Constructor	Description
VarHandleGenerator()

Method Summary

Modifier and Type	Method	Description
long	costOfGetNanos()	Returns the approximate cost to read the generation.
long	costOfSetNanos()	Returns the approximate cost to change the generation.
long	getGeneration()	Gets the current generation, shifted left by Generator.GEN_OFFSET.
void	setGeneration(long generation)	Sets the current generation count.

Methods inherited from class java.lang.Object

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

Field Details

GEN

private static final VarHandle GEN

gen

private long gen

Constructor Details

VarHandleGenerator

public VarHandleGenerator()

Method Details

setGeneration

public void setGeneration(long generation)

Description copied from class: Generator

Sets the current generation count. This should be eventually noticeable for callers of Generator.getGeneration(). An odd number means the library is enabled, while an even number means the library is disabled.

Overrides:

setGeneration in class Generator

Parameters:

generation - the generation id, shifted left by Generator.GEN_OFFSET.

getGeneration

public long getGeneration()

Description copied from class: Generator

Gets the current generation, shifted left by Generator.GEN_OFFSET. An odd number means the library is enabled, while an even number means the library is disabled.

Overrides:

getGeneration in class Generator

Returns:

the current generation or Generator.FAILURE.

costOfSetNanos

public long costOfSetNanos()

Description copied from class: Generator

Returns the approximate cost to change the generation.

Overrides:

costOfSetNanos in class Generator

Returns:

an approximate number of nanoseconds needed to change the generator value.

costOfGetNanos

public long costOfGetNanos()

Description copied from class: Generator

Returns the approximate cost to read the generation.

Overrides:

costOfGetNanos in class Generator

Returns:

an approximate number of nanoseconds needed to read the generator value.