com.gemstone.gemfire.internal.shared.unsafe

Class DirectBufferAllocator

java.lang.Object

com.gemstone.gemfire.internal.shared.BufferAllocator

com.gemstone.gemfire.internal.shared.unsafe.DirectBufferAllocator

All Implemented Interfaces:

java.io.Closeable, java.lang.AutoCloseable

public class DirectBufferAllocator
extends BufferAllocator

Generic implementation of BufferAllocator for direct ByteBuffers using Java NIO API.

Field Summary

Fields

Modifier and Type	Field and Description
static int	DIRECT_OBJECT_OVERHEAD Overhead of allocation on off-heap memory is kept fixed at 8 even though actual overhead will be dependent on the malloc implementation.
static java.lang.String	DIRECT_STORE_DATA_FRAME_OUTPUT
static java.lang.String	DIRECT_STORE_OBJECT_OWNER The owner of direct buffers that are stored in Regions and tracked in UMM.

Fields inherited from class com.gemstone.gemfire.internal.shared.BufferAllocator

EXECUTION, STORE_DATA_FRAME_OUTPUT

Constructor Summary

Constructors

Modifier	Constructor and Description
protected	DirectBufferAllocator()

Method Summary

Modifier and Type	Method and Description
java.nio.ByteBuffer	allocate(int size, java.lang.String owner) Allocate a new ByteBuffer of given size.
java.nio.ByteBuffer	allocateForStorage(int size) Allocate a new ByteBuffer of given size for storage in a Region.
java.nio.ByteBuffer	allocateWithFallback(int size, java.lang.String owner) Allocate using the default allocator and fallback to base JDK one in case allocation fails due to some reason (e.g.
java.lang.Object	baseObject(java.nio.ByteBuffer buffer) Get the base object of the ByteBuffer for raw reads/writes by Unsafe API.
long	baseOffset(java.nio.ByteBuffer buffer) Get the base offset of the ByteBuffer for raw reads/writes by Unsafe API.
void	changeOwnerToStorage(java.nio.ByteBuffer buffer, int capacity, java.util.function.BiConsumer<java.lang.String,java.lang.Object> changeOwner)
void	clearPostAllocate(java.nio.ByteBuffer buffer, int position) Clears the memory to be zeros immediately after allocation from given position to end.
void	close() Any cleanup required at system close.
java.nio.ByteBuffer	expand(java.nio.ByteBuffer buffer, int required, java.lang.String owner) Expand given ByteBuffer to new capacity.
java.nio.ByteBuffer	fromBytesToStorage(byte[] bytes, int offset, int length) Return a ByteBuffer either copying from, or sharing the given heap bytes.
DirectBufferAllocator	initialize()
static DirectBufferAllocator	instance()
boolean	isDirect() Indicates if this allocator will produce direct ByteBuffers.
java.lang.RuntimeException	lowMemoryException(java.lang.String op, int required)
static void	resetInstance()
static void	setInstance(DirectBufferAllocator allocator)
java.nio.ByteBuffer	transfer(java.nio.ByteBuffer buffer, java.lang.String owner) Return a ByteBuffer either sharing data of given ByteBuffer if its type matches, or else copying from the given ByteBuffer.

Methods inherited from class com.gemstone.gemfire.internal.shared.BufferAllocator

allocateCustom, expandedSize, fill, fill, isManagedDirect, release, releaseBuffer, toBytes

Methods inherited from class java.lang.Object

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

Field Detail

DIRECT_OBJECT_OVERHEAD

public static final int DIRECT_OBJECT_OVERHEAD

Overhead of allocation on off-heap memory is kept fixed at 8 even though actual overhead will be dependent on the malloc implementation.

See Also:

Constant Field Values

DIRECT_STORE_OBJECT_OWNER

public static final java.lang.String DIRECT_STORE_OBJECT_OWNER

The owner of direct buffers that are stored in Regions and tracked in UMM.

See Also:

Constant Field Values

DIRECT_STORE_DATA_FRAME_OUTPUT

public static final java.lang.String DIRECT_STORE_DATA_FRAME_OUTPUT

See Also:

Constant Field Values

Constructor Detail

DirectBufferAllocator

protected DirectBufferAllocator()

Method Detail

instance

public static DirectBufferAllocator instance()

initialize

public DirectBufferAllocator initialize()

setInstance

public static void setInstance(DirectBufferAllocator allocator)

resetInstance

public static void resetInstance()

lowMemoryException

public java.lang.RuntimeException lowMemoryException(java.lang.String op,
                                                     int required)

changeOwnerToStorage

public void changeOwnerToStorage(java.nio.ByteBuffer buffer,
                                 int capacity,
                                 java.util.function.BiConsumer<java.lang.String,java.lang.Object> changeOwner)

allocate

public java.nio.ByteBuffer allocate(int size,
                                    java.lang.String owner)

Description copied from class: BufferAllocator

Allocate a new ByteBuffer of given size.

Specified by:

allocate in class BufferAllocator

allocateWithFallback

public java.nio.ByteBuffer allocateWithFallback(int size,
                                                java.lang.String owner)

Description copied from class: BufferAllocator

Allocate using the default allocator and fallback to base JDK one in case allocation fails due to some reason (e.g. system stop).

Overrides:

allocateWithFallback in class BufferAllocator

allocateForStorage

public java.nio.ByteBuffer allocateForStorage(int size)

Description copied from class: BufferAllocator

Allocate a new ByteBuffer of given size for storage in a Region.

Specified by:

allocateForStorage in class BufferAllocator

clearPostAllocate

public void clearPostAllocate(java.nio.ByteBuffer buffer,
                              int position)

Description copied from class: BufferAllocator

Clears the memory to be zeros immediately after allocation from given position to end.

Specified by:

clearPostAllocate in class BufferAllocator

baseObject

public java.lang.Object baseObject(java.nio.ByteBuffer buffer)

Description copied from class: BufferAllocator

Get the base object of the ByteBuffer for raw reads/writes by Unsafe API.

Specified by:

baseObject in class BufferAllocator

baseOffset

public long baseOffset(java.nio.ByteBuffer buffer)

Description copied from class: BufferAllocator

Get the base offset of the ByteBuffer for raw reads/writes by Unsafe API.

Specified by:

baseOffset in class BufferAllocator

expand

public java.nio.ByteBuffer expand(java.nio.ByteBuffer buffer,
                                  int required,
                                  java.lang.String owner)

Description copied from class: BufferAllocator

Expand given ByteBuffer to new capacity. The new buffer is positioned at the start and caller has to reposition if required. The ByteOrder will be copied from the source buffer.

Specified by:

expand in class BufferAllocator

Returns:

the new expanded ByteBuffer

fromBytesToStorage

public java.nio.ByteBuffer fromBytesToStorage(byte[] bytes,
                                              int offset,
                                              int length)

Description copied from class: BufferAllocator

Return a ByteBuffer either copying from, or sharing the given heap bytes.

Specified by:

fromBytesToStorage in class BufferAllocator

transfer

public java.nio.ByteBuffer transfer(java.nio.ByteBuffer buffer,
                                    java.lang.String owner)

Description copied from class: BufferAllocator

Return a ByteBuffer either sharing data of given ByteBuffer if its type matches, or else copying from the given ByteBuffer.

Overrides:

transfer in class BufferAllocator

isDirect

public boolean isDirect()

Description copied from class: BufferAllocator

Indicates if this allocator will produce direct ByteBuffers.

Specified by:

isDirect in class BufferAllocator

close

public void close()

Description copied from class: BufferAllocator

Any cleanup required at system close.

Specified by:

close in interface java.io.Closeable

Specified by:

close in interface java.lang.AutoCloseable

Specified by:

close in class BufferAllocator