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.

Method Summary

Modifier and Type	Method and Description
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 int	compileThreshold()
static ExceptionHandler	debug()
static void	disableDebugHandler()
static void	dumpException(Map<ExceptionKey,Integer> exceptions)
static ExceptionHandler	fatal()
static Field	getField(Class clazz, String name) Get the Field for a class by name.
static int	getProcessId()
static <V> V	getValue(Object obj, String name)
static boolean	hasException(Map<ExceptionKey,Integer> exceptions)
static boolean	is64bit()
static boolean	isDebug()
static boolean	isDebugEnabled(Class aClass)
static boolean	isFlightRecorder()
static boolean	isJava9Plus()
static String	lockWithStack(ReentrantLock lock) Log the stack trace of the thread holding a lock.
static int	majorVersion()
static long	maxDirectMemory()
static void	optionalSafepoint()
static void	pause(long millis) Silently pause for milli seconds.
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	setExceptionHandlers(ExceptionHandler fatal, ExceptionHandler warn, ExceptionHandler debug)
static void	setExceptionsHandlers(ExceptionHandler fatal, ExceptionHandler warn, ExceptionHandler debug) Deprecated.
static void	setThreadLocalExceptionHandlers(ExceptionHandler fatal, ExceptionHandler warn, ExceptionHandler debug)
static void	signalHandler(sun.misc.SignalHandler signalHandler) Helper method for setting the default signals.
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 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

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

compileThreshold

public static int compileThreshold()

majorVersion

public static int majorVersion()

isJava9Plus

public static boolean isJava9Plus()

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.

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.

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)

setThreadLocalExceptionHandlers

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

fatal

@NotNull
public static ExceptionHandler fatal()

warn

@NotNull
public static ExceptionHandler warn()

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

public static void optionalSafepoint()