com.hazelcast.internal.memory

Interface MemoryAllocator

All Superinterfaces:

Disposable

public interface MemoryAllocator
extends Disposable

Manages the usage of an address space by allocating and freeing blocks of addresses.

Field Summary

Fields

Modifier and Type	Field and Description
static long	NULL_ADDRESS The special value that does not correspond to an actual address and signals the absence of an address.

Method Summary

Methods

Modifier and Type	Method and Description
long	allocate(long size) Allocates a block of addresses with the requested size and returns the base address of the block.
void	free(long address, long size) Accepts the base address and size of a previously allocated block and sets it free.
long	reallocate(long address, long currentSize, long newSize) Accepts the base address and size of a previously allocated block and "reallocates" it by either: Resizing the existing block, if possible.

Methods inherited from interface com.hazelcast.nio.Disposable

dispose

Field Detail

NULL_ADDRESS

static final long NULL_ADDRESS

The special value that does not correspond to an actual address and signals the absence of an address.

See Also:

Constant Field Values

Method Detail

allocate

long allocate(long size)

Allocates a block of addresses with the requested size and returns the base address of the block. The contents of the block will be initialized to the zero value.

Guarantees that no subsequent call to allocate() will allocate a block which overlaps the currently allocated block. The guarantee holds until the block is free(long, long)'d.

Parameters:

size - size of the block to allocate

Returns:

the base address of the allocated block

Throws:

NativeOutOfMemoryError - if there is not enough free memory to satisfy the reallocation request.

reallocate

long reallocate(long address,
              long currentSize,
              long newSize)

Accepts the base address and size of a previously allocated block and "reallocates" it by either:

1. Resizing the existing block, if possible. The contents of the block remain unchanged up to the lesser of the new and old sizes.
2. Allocating a new block of newSize, copying the contents of the old block into it (up to the new block's size), then freeing the old block.

The part of the new block which extends beyond the size of the current block (if any) will be initialized to the zero value.

Parameters:

address - base address of the block

currentSize - size of the block

newSize - requested new block size

Returns:

base address of the reallocated block

Throws:

NativeOutOfMemoryError - if there is not enough free memory to satisfy the reallocation request.

free

void free(long address,
        long size)

Accepts the base address and size of a previously allocated block and sets it free. All the addresses contained in the block are free to be allocated by future allocation/reallocation requests.

Parameters:

address - base address of the block

size - size of the block