Package one.microstream.memory

Class PlatformInternals

java.lang.Object

one.microstream.memory.PlatformInternals

public class PlatformInternals
extends Object

This class provides static utility functionality to access certain required access to internal JDK logic without using JDK-version-specific dependencies. E.g. JDK-internal classes in the "sun.*" package were moved to the "jdk.*" package but access to those is required to compensate for certain shortcomings in the JDK's public API.

This class does the magic trick of allowing JDK-specific access without having JDK-specific dependencies in the source code. Congratulations and felicitation always welcomed.

In more general terms, this class abstracts platform-version-specific details.

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
static interface	PlatformInternals.Warning

Constructor Summary

Constructors

Constructor	Description
PlatformInternals()

Method Summary

Modifier and Type	Method	Description
static void	deallocateDirectBuffer(ByteBuffer directBuffer)	No idea if this method is really (still?) necesssary, but it sounds reasonable.
static byte[]	directBufferToArray(ByteBuffer directBuffer)
static ByteBuffer	ensureDirectBufferCapacity(ByteBuffer current, long capacity)
static Class<?>	getClassCleaner()
static Class<?>	getClassDirectbuffer()
static long	getDirectBufferAddress(ByteBuffer directBuffer)
static DirectBufferAddressGetter	getDirectBufferAddressGetter()
static DirectBufferDeallocator	getDirectBufferDeallocator()
static String	getResolvingStatus()
static <DB extends ByteBuffer> DB	guaranteeDirectBuffer(DB directBuffer)
static void	guaranteeUsability()	Guarantees the usability of this class by validating if all functionality is usable.
static XGettingSequence<PlatformInternals.Warning>	initializationWarnings()
static boolean	isDirectBuffer(ByteBuffer directBuffer)	Just to have all jdk internal types here at one place.
static void	printInitializationWarnings(PrintStream printStream)
static void	setDirectBufferAddressGetter(DirectBufferAddressGetter addressGetter)	Allows to set the DirectBufferAddressGetter used bygetDirectBufferAddress(ByteBuffer) as an override to the means this class inherently tries to provide. See DirectBufferAddressGetter for details.
static void	setDirectBufferDeallocator(DirectBufferDeallocator deallocator)	Allows to set the DirectBufferDeallocator used bydeallocateDirectBuffer(ByteBuffer) as an override to the means this class inherently tries to provide. See DirectBufferDeallocator for details.

Methods inherited from class java.lang.Object

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

Constructor Detail

PlatformInternals

public PlatformInternals()

Method Detail

setDirectBufferDeallocator

public static void setDirectBufferDeallocator(DirectBufferDeallocator deallocator)

Allows to set the DirectBufferDeallocator used bydeallocateDirectBuffer(ByteBuffer) as an override to the means this class inherently tries to provide.
See DirectBufferDeallocator for details.

The passed instance "should" be immutable or better stateless to ensure concurrency-safe usage, but ultimately, the responsibility resides with the author of the instance's implementation.

Passing a null resets the behavior of deallocateDirectBuffer(ByteBuffer) to the inherent logic.

Parameters:

deallocator - the deallocator to be used, potentially null.

See Also:

DirectBufferDeallocator

getDirectBufferDeallocator

public static DirectBufferDeallocator getDirectBufferDeallocator()

setDirectBufferAddressGetter

public static void setDirectBufferAddressGetter(DirectBufferAddressGetter addressGetter)

Allows to set the DirectBufferAddressGetter used bygetDirectBufferAddress(ByteBuffer) as an override to the means this class inherently tries to provide.
See DirectBufferAddressGetter for details.

The passed instance "should" be immutable or better stateless to ensure concurrency-safe usage, but ultimately, the responsibility resides with the author of the instance's implementation.

Passing a null resets the behavior of getDirectBufferAddress(ByteBuffer) to the inherent logic.

Parameters:

addressGetter - the addressGetter to be used, potentially null.

See Also:

DirectBufferDeallocator

getDirectBufferAddressGetter

public static DirectBufferAddressGetter getDirectBufferAddressGetter()

getClassDirectbuffer

public static Class<?> getClassDirectbuffer()

getClassCleaner

public static Class<?> getClassCleaner()

guaranteeUsability

public static void guaranteeUsability()

Guarantees the usability of this class by validating if all functionality is usable. This does not necessarily mean that all attempts to resolve JDK-internal code structures were successful. Some have alternative options that are used as a fallback.

Throws:

Error

isDirectBuffer

public static final boolean isDirectBuffer(ByteBuffer directBuffer)

Just to have all jdk internal types here at one place.

Parameters:

directBuffer -

guaranteeDirectBuffer

public static final <DB extends ByteBuffer> DB guaranteeDirectBuffer(DB directBuffer)

ensureDirectBufferCapacity

public static final ByteBuffer ensureDirectBufferCapacity(ByteBuffer current,
                                                          long capacity)

deallocateDirectBuffer

public static final void deallocateDirectBuffer(ByteBuffer directBuffer)

No idea if this method is really (still?) necesssary, but it sounds reasonable. See http://stackoverflow.com/questions/8462200/examples-of-forcing-freeing-of-native-memory-direct-bytebuffer-has-allocated-us

Parameters:

directBuffer -

getDirectBufferAddress

public static final long getDirectBufferAddress(ByteBuffer directBuffer)

directBufferToArray

public static final byte[] directBufferToArray(ByteBuffer directBuffer)

getResolvingStatus

public static final String getResolvingStatus()

initializationWarnings

public static final XGettingSequence<PlatformInternals.Warning> initializationWarnings()

printInitializationWarnings

public static final void printInitializationWarnings(PrintStream printStream)