com.gemstone.gemfire.internal.shared

Class BufferAllocator

java.lang.Object

com.gemstone.gemfire.internal.shared.BufferAllocator

All Implemented Interfaces:

java.io.Closeable, java.lang.AutoCloseable

Direct Known Subclasses:

DirectBufferAllocator, HeapBufferAllocator

public abstract class BufferAllocator
extends java.lang.Object
implements java.io.Closeable

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

Field Summary

Fields

Modifier and Type	Field and Description
static java.lang.String	EXECUTION Special owner indicating execution pool memory.
static java.lang.String	STORE_DATA_FRAME_OUTPUT

Constructor Summary

Constructors

Constructor and Description
BufferAllocator()

Method Summary

Modifier and Type	Method and Description
abstract java.nio.ByteBuffer	allocate(int size, java.lang.String owner) Allocate a new ByteBuffer of given size.
java.nio.ByteBuffer	allocateCustom(int size, FreeMemory.Factory factory) Allocate a buffer passing a custom FreeMemoryFactory.
abstract 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.
abstract java.lang.Object	baseObject(java.nio.ByteBuffer buffer) Get the base object of the ByteBuffer for raw reads/writes by Unsafe API.
abstract long	baseOffset(java.nio.ByteBuffer buffer) Get the base offset of the ByteBuffer for raw reads/writes by Unsafe API.
abstract void	clearPostAllocate(java.nio.ByteBuffer buffer, int position) Clears the memory to be zeros immediately after allocation from given position to end.
abstract void	close() Any cleanup required at system close.
abstract java.nio.ByteBuffer	expand(java.nio.ByteBuffer buffer, int required, java.lang.String owner) Expand given ByteBuffer to new capacity.
protected static int	expandedSize(int currentUsed, int required)
void	fill(java.nio.ByteBuffer buffer, byte b) Fill the buffer from its current position to full capacity with given byte.
void	fill(java.nio.ByteBuffer buffer, byte b, int position, int numBytes) Fill the given portion of the buffer setting it with given byte.
abstract java.nio.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.
boolean	isManagedDirect() Return true if this is a managed direct buffer allocator.
void	release(java.nio.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.
static boolean	releaseBuffer(java.nio.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(java.nio.ByteBuffer buffer) Return the data as a heap byte array.
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 java.lang.Object

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

Field Detail

STORE_DATA_FRAME_OUTPUT

public static final java.lang.String STORE_DATA_FRAME_OUTPUT

See Also:

Constant Field Values

EXECUTION

public static final java.lang.String EXECUTION

Special owner indicating execution pool memory.

See Also:

Constant Field Values

Constructor Detail

BufferAllocator

public BufferAllocator()

Method Detail

allocate

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

Allocate a new ByteBuffer of given size.

allocateWithFallback

public 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. system stop).

allocateForStorage

public abstract java.nio.ByteBuffer allocateForStorage(int size)

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

clearPostAllocate

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

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

fill

public final void fill(java.nio.ByteBuffer buffer,
                       byte b,
                       int position,
                       int numBytes)

Fill the given portion of the buffer setting it with given byte.

fill

public final void fill(java.nio.ByteBuffer buffer,
                       byte b)

Fill the buffer from its current position to full capacity with given byte.

baseObject

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

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

baseOffset

public abstract long baseOffset(java.nio.ByteBuffer buffer)

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

expand

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

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.

Returns:

the new expanded ByteBuffer

toBytes

public byte[] toBytes(java.nio.ByteBuffer buffer)

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

fromBytesToStorage

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

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

transfer

public 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.

release

public final void release(java.nio.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.

releaseBuffer

public static boolean releaseBuffer(java.nio.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.

isManagedDirect

public boolean isManagedDirect()

Return true if this is a managed direct buffer allocator.

allocateCustom

public java.nio.ByteBuffer allocateCustom(int size,
                                          FreeMemory.Factory factory)

Allocate a buffer passing a custom FreeMemoryFactory. Requires that appropriate calls against Spark memory manager have already been done. Only for managed buffer allocator.

close

public abstract void close()

Any cleanup required at system close.

Specified by:

close in interface java.io.Closeable

Specified by:

close in interface java.lang.AutoCloseable

expandedSize

protected static int expandedSize(int currentUsed,
                                  int required)