net.openhft.chronicle.core

Enum Jvm

java.lang.Object

java.lang.Enum<Jvm>

net.openhft.chronicle.core.Jvm

All Implemented Interfaces:

Serializable, Comparable<Jvm>

public enum Jvm
extends Enum<Jvm>

Utility class to access information in the JVM.

Field Summary

Fields

Modifier and Type	Field and Description
static String	JAVA_CLASS_PATH

Method Summary

Modifier and Type	Method and Description
static long	address(ByteBuffer bb)
static void	addToClassPath(Class clazz) Makes sure all the jars etc in the current class loader have been added to the class path.
static boolean	areOptionalSafepointsEnabled()
static int	arrayByteBaseOffset()
static void	busyWaitMicros(long micros) This method is designed to be used when the time to be waited is very small, typically under a millisecond.
static void	busyWaitUntil(long waitUntil) This method is designed to be used when the time to be waited is very small, typically under a millisecond.
static ClassMetrics	classMetrics(Class c)
static int	compileThreshold()
static ExceptionHandler	debug()
static void	disableDebugHandler()
static void	doNotCloseOnInterrupt(Class clazz, FileChannel fc)
static boolean	dontChain(Class tClass)
static void	dumpException(Map<ExceptionKey,Integer> exceptions)
static ExceptionHandler	fatal()
static boolean	getBoolean(String property) A more permissive boolean System property flag.
static boolean	getBoolean(String property, boolean defaultValue) A more permissive boolean System property flag.
static double	getDouble(String property, double defaultValue)
static Field	getField(Class clazz, String name) Get the Field for a class by name.
static Method	getMethod(Class clazz, String name, Class... args)
static int	getProcessId()
static <V> V	getValue(Object obj, String name)
static boolean	hasException(Map<ExceptionKey,Integer> exceptions)
static void	init()
static boolean	is64bit()
static boolean	isArm()
static boolean	isDebug()
static boolean	isDebugEnabled(Class aClass)
static boolean	isFlightRecorder()
static boolean	isJava12Plus()
static boolean	isJava14Plus()
static boolean	isJava9Plus()
static boolean	isProcessAlive(long pid) checks if a process is still alive
static boolean	isResourceTracing()
static String	lockWithStack(ReentrantLock lock) Log the stack trace of the thread holding a lock.
static int	majorVersion()
static long	maxDirectMemory()
static void	nanoPause() Pause in a busy loop for a very short time.
static void	optionalSafepoint() Deprecated.
static void	pause(long millis) Silently pause for milli seconds.
static ExceptionHandler	perf()
static Map<ExceptionKey,Integer>	recordExceptions()
static Map<ExceptionKey,Integer>	recordExceptions(boolean debug)
static Map<ExceptionKey,Integer>	recordExceptions(boolean debug, boolean exceptionsOnly)
static Map<ExceptionKey,Integer>	recordExceptions(boolean debug, boolean exceptionsOnly, boolean logToSlf4j)
static void	resetExceptionHandlers()
static <T extends Throwable> RuntimeException	rethrow(Throwable throwable) Cast a CheckedException as an unchecked one.
static void	safepoint()
static void	setAccessible(AccessibleObject h)
static void	setExceptionHandlers(ExceptionHandler fatal, ExceptionHandler warn, ExceptionHandler debug)
static void	setExceptionHandlers(ExceptionHandler fatal, ExceptionHandler warn, ExceptionHandler debug, ExceptionHandler perf)
static void	setExceptionsHandlers(ExceptionHandler fatal, ExceptionHandler warn, ExceptionHandler debug) Deprecated.
static void	setThreadLocalExceptionHandlers(ExceptionHandler fatal, ExceptionHandler warn, ExceptionHandler debug)
static void	setThreadLocalExceptionHandlers(ExceptionHandler fatal, ExceptionHandler warn, ExceptionHandler debug, ExceptionHandler perf)
static void	signalHandler(sun.misc.SignalHandler signalHandler) Helper method for setting the default signals.
static boolean	stackTraceEndsWith(String endsWith, int n)
static int	trimLast(int first, StackTraceElement[] stes)
static void	trimStackTrace(StringBuilder sb, StackTraceElement... stes) Append the StackTraceElements to the StringBuilder trimming some internal methods.
static long	usedDirectMemory()
static long	usedNativeMemory()
static String	userHome()
static Jvm	valueOf(String name) Returns the enum constant of this type with the specified name.
static Jvm[]	values() Returns an array containing the constants of this enum type, in the order they are declared.
static ExceptionHandler	warn()

Methods inherited from class java.lang.Enum

clone, compareTo, equals, finalize, getDeclaringClass, hashCode, name, ordinal, toString, valueOf

Methods inherited from class java.lang.Object

getClass, notify, notifyAll, wait, wait, wait

Field Detail

JAVA_CLASS_PATH

public static final String JAVA_CLASS_PATH

See Also:

Constant Field Values

Method Detail

values

public static Jvm[] values()

Returns an array containing the constants of this enum type, in the order they are declared. This method may be used to iterate over the constants as follows:

for (Jvm c : Jvm.values())
    System.out.println(c);

Returns:

an array containing the constants of this enum type, in the order they are declared

valueOf

public static Jvm valueOf(String name)

Returns the enum constant of this type with the specified name. The string must match exactly an identifier used to declare an enum constant in this type. (Extraneous whitespace characters are not permitted.)

Parameters:

name - the name of the enum constant to be returned.

Returns:

the enum constant with the specified name

Throws:

IllegalArgumentException - if this enum type has no constant with the specified name

NullPointerException - if the argument is null

init

public static void init()

compileThreshold

public static int compileThreshold()

majorVersion

public static int majorVersion()

isJava9Plus

public static boolean isJava9Plus()

isJava12Plus

public static boolean isJava12Plus()

isJava14Plus

public static boolean isJava14Plus()

getProcessId

public static int getProcessId()

rethrow

@NotNull
public static <T extends Throwable> RuntimeException rethrow(Throwable throwable)
                                                               throws T extends Throwable

Cast a CheckedException as an unchecked one.

Type Parameters:

T - the type of the Throwable

Parameters:

throwable - to cast

Returns:

this method will never return a Throwable instance, it will just throw it.

Throws:

T - the throwable as an unchecked throwable

T extends Throwable

trimStackTrace

public static void trimStackTrace(@NotNull
                                  StringBuilder sb,
                                  @NotNull
                                  StackTraceElement... stes)

Append the StackTraceElements to the StringBuilder trimming some internal methods.

Parameters:

sb - to append to

stes - stack trace elements

trimLast

public static int trimLast(int first,
                           @NotNull
                           StackTraceElement[] stes)

isDebug

public static boolean isDebug()

Returns:

is the JVM in debug mode.

isFlightRecorder

public static boolean isFlightRecorder()

Returns:

is the JVM in flight recorder mode.

pause

public static void pause(long millis)

Silently pause for milli seconds.

Parameters:

millis - to sleep for.

nanoPause

public static void nanoPause()

Pause in a busy loop for a very short time.

busyWaitMicros

public static void busyWaitMicros(long micros)

This method is designed to be used when the time to be waited is very small, typically under a millisecond.

Parameters:

micros - Time in micros

busyWaitUntil

public static void busyWaitUntil(long waitUntil)

This method is designed to be used when the time to be waited is very small, typically under a millisecond.

Parameters:

waitUntil - nanosecond precision counter value to await.

getField

public static Field getField(@NotNull
                             Class clazz,
                             @NotNull
                             String name)

Get the Field for a class by name.

Parameters:

clazz - to get the field for

name - of the field

Returns:

the Field.

getMethod

public static Method getMethod(@NotNull
                               Class clazz,
                               @NotNull
                               String name,
                               Class... args)

setAccessible

public static void setAccessible(AccessibleObject h)

getValue

public static <V> V getValue(@NotNull
                             Object obj,
                             @NotNull
                             String name)

lockWithStack

public static String lockWithStack(@NotNull
                                   ReentrantLock lock)

Log the stack trace of the thread holding a lock.

Parameters:

lock - to log

Returns:

the lock.toString plus a stack trace.

usedDirectMemory

public static long usedDirectMemory()

Returns:

The size of memory used by direct ByteBuffers i.e. ByteBuffer.allocateDirect()

usedNativeMemory

public static long usedNativeMemory()

Returns:

The size of memory used by UnsafeMemory.allocate()

maxDirectMemory

public static long maxDirectMemory()

is64bit

public static boolean is64bit()

resetExceptionHandlers

public static void resetExceptionHandlers()

disableDebugHandler

public static void disableDebugHandler()

recordExceptions

@NotNull
public static Map<ExceptionKey,Integer> recordExceptions()

recordExceptions

@NotNull
public static Map<ExceptionKey,Integer> recordExceptions(boolean debug)

recordExceptions

@NotNull
public static Map<ExceptionKey,Integer> recordExceptions(boolean debug,
                                                                  boolean exceptionsOnly)

recordExceptions

@NotNull
public static Map<ExceptionKey,Integer> recordExceptions(boolean debug,
                                                                  boolean exceptionsOnly,
                                                                  boolean logToSlf4j)

hasException

public static boolean hasException(@NotNull
                                   Map<ExceptionKey,Integer> exceptions)

setExceptionsHandlers

@Deprecated
public static void setExceptionsHandlers(@Nullable
                                                     ExceptionHandler fatal,
                                                     @Nullable
                                                     ExceptionHandler warn,
                                                     @Nullable
                                                     ExceptionHandler debug)

Deprecated.

setExceptionHandlers

public static void setExceptionHandlers(@Nullable
                                        ExceptionHandler fatal,
                                        @Nullable
                                        ExceptionHandler warn,
                                        @Nullable
                                        ExceptionHandler debug)

setExceptionHandlers

public static void setExceptionHandlers(@Nullable
                                        ExceptionHandler fatal,
                                        @Nullable
                                        ExceptionHandler warn,
                                        @Nullable
                                        ExceptionHandler debug,
                                        @Nullable
                                        ExceptionHandler perf)

setThreadLocalExceptionHandlers

public static void setThreadLocalExceptionHandlers(@Nullable
                                                   ExceptionHandler fatal,
                                                   @Nullable
                                                   ExceptionHandler warn,
                                                   @Nullable
                                                   ExceptionHandler debug)

setThreadLocalExceptionHandlers

public static void setThreadLocalExceptionHandlers(@Nullable
                                                   ExceptionHandler fatal,
                                                   @Nullable
                                                   ExceptionHandler warn,
                                                   @Nullable
                                                   ExceptionHandler debug,
                                                   @Nullable
                                                   ExceptionHandler perf)

fatal

@NotNull
public static ExceptionHandler fatal()

warn

@NotNull
public static ExceptionHandler warn()

perf

@NotNull
public static ExceptionHandler perf()

debug

@NotNull
public static ExceptionHandler debug()

dumpException

public static void dumpException(@NotNull
                                 Map<ExceptionKey,Integer> exceptions)

isDebugEnabled

public static boolean isDebugEnabled(Class aClass)

signalHandler

public static void signalHandler(sun.misc.SignalHandler signalHandler)

Helper method for setting the default signals. Every signal handler you register with this method will be called.

Parameters:

signalHandler - to call on a signal

safepoint

public static void safepoint()

optionalSafepoint

@Deprecated
public static void optionalSafepoint()

Deprecated.

areOptionalSafepointsEnabled

public static boolean areOptionalSafepointsEnabled()

stackTraceEndsWith

public static boolean stackTraceEndsWith(String endsWith,
                                         int n)

isArm

public static boolean isArm()

classMetrics

public static ClassMetrics classMetrics(Class c)
                                 throws IllegalArgumentException

Throws:

IllegalArgumentException

userHome

public static String userHome()

dontChain

public static boolean dontChain(Class tClass)

isResourceTracing

public static boolean isResourceTracing()

getBoolean

public static boolean getBoolean(String property)

A more permissive boolean System property flag. -Dflag-Dflag=true-Dflag=yes are all accepted

Parameters:

property - name to lookup

Returns:

if true or set

getBoolean

public static boolean getBoolean(String property,
                                 boolean defaultValue)

A more permissive boolean System property flag. -Dflag-Dflag=true-Dflag=yes are all accepted

Parameters:

property - name to lookup

defaultValue - value to be used if unknown

Returns:

if true or set

address

public static long address(ByteBuffer bb)

arrayByteBaseOffset

public static int arrayByteBaseOffset()

doNotCloseOnInterrupt

public static void doNotCloseOnInterrupt(Class clazz,
                                         FileChannel fc)

addToClassPath

public static void addToClassPath(Class clazz)

Makes sure all the jars etc in the current class loader have been added to the class path.

Parameters:

clazz - to use as a template.

getDouble

public static double getDouble(String property,
                               double defaultValue)

isProcessAlive

public static boolean isProcessAlive(long pid)

checks if a process is still alive

Parameters:

pid -

Returns:

true if the process is still alive