com.gemstone.gemfire.internal.shared

Class BufferAllocator

java.lang.Object

com.gemstone.gemfire.internal.shared.BufferAllocator

All Implemented Interfaces:

Closeable, AutoCloseable

Direct Known Subclasses:

DirectBufferAllocator, HeapBufferAllocator

public abstract class BufferAllocator
extends Object
implements Closeable

Allocate, release and expand ByteBuffers (in-place if possible).

Field Summary

Fields

Modifier and Type	Field and Description
static String	STORE_DATA_FRAME_OUTPUT

Constructor Summary

Constructors

Constructor and Description
BufferAllocator()

Method Summary

Modifier and Type	Method and Description
abstract ByteBuffer	allocate(int size, String owner) Allocate a new ByteBuffer of given size.
abstract ByteBuffer	allocateForStorage(int size) Allocate a new ByteBuffer of given size for storage in a Region.
abstract Object	baseObject(ByteBuffer buffer) Get the base object of the ByteBuffer for raw reads/writes by Unsafe API.
abstract long	baseOffset(ByteBuffer buffer) Get the base offset of the ByteBuffer for raw reads/writes by Unsafe API.
void	clearBuffer(ByteBuffer buffer, int position, int numBytes) Clear the given portion of the buffer setting it with zeros.
abstract void	clearPostAllocate(ByteBuffer buffer) Clears the memory to be zeros immediately after allocation.
abstract void	close() Any cleanup required at system close.
abstract ByteBuffer	expand(ByteBuffer buffer, int required, String owner) Expand given ByteBuffer to new capacity.
static int	expandedSize(int currentUsed, int required)
abstract ByteBuffer	fromBytesToStorage(byte[] bytes, int offset, int length) Return a ByteBuffer either copying from, or sharing the given heap bytes.
abstract boolean	isDirect() Indicates if this allocator will produce direct ByteBuffers.
abstract void	release(ByteBuffer buffer) For direct ByteBuffers the release method is preferred to eagerly release the memory instead of depending on heap GC which can be delayed.
byte[]	toBytes(ByteBuffer buffer) Return the data as a heap byte array.
ByteBuffer	transfer(ByteBuffer buffer, 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 java.lang.Object

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

Field Detail

STORE_DATA_FRAME_OUTPUT

public static final String STORE_DATA_FRAME_OUTPUT

See Also:

Constant Field Values

Constructor Detail

BufferAllocator

public BufferAllocator()

Method Detail

allocate

public abstract ByteBuffer allocate(int size,
                                    String owner)

Allocate a new ByteBuffer of given size.

allocateForStorage

public abstract ByteBuffer allocateForStorage(int size)

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

clearPostAllocate

public abstract void clearPostAllocate(ByteBuffer buffer)

Clears the memory to be zeros immediately after allocation.

clearBuffer

public final void clearBuffer(ByteBuffer buffer,
                              int position,
                              int numBytes)

Clear the given portion of the buffer setting it with zeros.

baseObject

public abstract Object baseObject(ByteBuffer buffer)

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

baseOffset

public abstract long baseOffset(ByteBuffer buffer)

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

expand

public abstract ByteBuffer expand(ByteBuffer buffer,
                                  int required,
                                  String owner)

Expand given ByteBuffer to new capacity. The new buffer is positioned at the start and caller has to reposition if required.

Returns:

the new expanded ByteBuffer

toBytes

public byte[] toBytes(ByteBuffer buffer)

Return the data as a heap byte array. Use of this should be minimal when no other option exists.

fromBytesToStorage

public abstract ByteBuffer fromBytesToStorage(byte[] bytes,
                                              int offset,
                                              int length)

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

transfer

public ByteBuffer transfer(ByteBuffer buffer,
                           String owner)

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

release

public abstract void release(ByteBuffer buffer)

For direct ByteBuffers the release method is preferred to eagerly release the memory instead of depending on heap GC which can be delayed.

isDirect

public abstract boolean isDirect()

Indicates if this allocator will produce direct ByteBuffers.

close

public abstract void close()

Any cleanup required at system close.

Specified by:

close in interface Closeable

Specified by:

close in interface AutoCloseable

expandedSize

public static int expandedSize(int currentUsed,
                               int required)