com.alexkasko.unsafe.offheapstruct

Class OffHeapStructArray

java.lang.Object

com.alexkasko.unsafe.offheapstruct.OffHeapStructArray

All Implemented Interfaces:

OffHeapDisposable, OffHeapDisposableIterable<byte[]>, OffHeapStructCollection, Iterable<byte[]>

public class OffHeapStructArray
extends Object
implements OffHeapStructCollection, OffHeapDisposable

Implementation of off-heap array of structs (memory areas of equal sizes).

Default implementation uses sun.misc.Unsafe, with all operations guarded with assert keyword. With assertions enabled in runtime (-ea java switch) AssertionError will be thrown on illegal index access. Without assertions illegal index will crash JVM.

Array won't be zeroed after creation (will contain garbage by default). Allocated memory may be freed manually using free() (thread-safe and may be called multiple times) or it will be freed after OffHeapStructArray instance will be garbage collected.

Author:

alexkasko Date: 7/3/13

Field Summary

Fields

Modifier and Type	Field and Description
private OffHeapMemory	ohm
private int	structLength

Constructor Summary

Constructors

Modifier	Constructor and Description
	OffHeapStructArray(ByteArrayTool bt, int size, int structLength) Constructor, uses OnHeapMemory underneath effectively making this instance an OnHeap collection
	OffHeapStructArray(long size, int structLength) Constructor
private	OffHeapStructArray(OffHeapMemory ohm, int structLength) Private constructor for clone() support

Method Summary

Methods

Modifier and Type	Method and Description
OffHeapStructArray	clone()
void	free() Frees allocated memory, may be called multiple times from any thread
void	get(long index, byte[] buffer) Copies struct on specified index into specified buffer
void	get(long index, byte[] buffer, int bufferPos) Copies struct on specified index into specified buffer
void	get(long index, int pos, byte[] buffer, int bufferPos, int length) Copies part of struct on specified index into specified buffer
byte	getByte(long index, int offset) Gets byte from struct on specified index with specified offset
int	getInt(long index, int offset) Gets four bytes as int from struct on specified index with specified offset
long	getLong(long index, int offset) Gets long from struct on specified index with specified offset
short	getShort(long index, int offset) Gets two bytes as short from struct on specified index with specified offset
short	getUnsignedByte(long index, int offset) Gets one byte (stored as one signed byte) from struct on specified index with specified offset, converts it to unsigned and returns it as short
long	getUnsignedInt(long index, int offset) Gets unsigned int (stored as 4 bytes) and returns it as long from struct on specified index with specified offset
int	getUnsignedShort(long index, int offset) Gets unsigned short (stored as two bytes) from struct on specified index with specified offset and returns it as int
boolean	isUnsafe() Whether unsafe implementation of OffHeapMemory is used
OffHeapDisposableIterator<byte[]>	iterator()
void	putByte(long index, int offset, byte value) Puts byte into struct onto specified index with specified offset
void	putInt(long index, int offset, int value) Puts int into struct onto specified index with specified offset as four bytes
void	putLong(long index, int offset, long value) Puts long into struct onto specified index with specified offset as eight bytes
void	putShort(long index, int offset, short value) Puts short into struct onto specified index with specified offset as two bytes
void	putUnsignedByte(long index, int offset, short value) Puts short with value from 0 to 255 inclusive into struct onto specified index with specified offset as one signed byte
void	putUnsignedInt(long index, int offset, long value) Puts long value from 0 to 4294967295 inclusive into struct onto specified index with specified offset as four bytes
void	putUnsignedShort(long index, int offset, int value) Puts int with value from 0 to 65535 inclusive into struct onto specified index with specified offset as two bytes
void	set(long index, byte[] struct) Copies specified struct contents onto specified index
void	set(long index, byte[] struct, int structPos) Copies specified struct contents onto specified index
long	size() Returns number of elements in this array
int	structLength() Returns length of the single struct in bytes
String	toString()

Methods inherited from class java.lang.Object

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

Field Detail

ohm

private final OffHeapMemory ohm

structLength

private final int structLength

Constructor Detail

OffHeapStructArray

public OffHeapStructArray(long size,
                  int structLength)

Constructor

Parameters:

size - array size

structLength - length of struct in bytes, must be >= 8

OffHeapStructArray

public OffHeapStructArray(ByteArrayTool bt,
                  int size,
                  int structLength)

Constructor, uses OnHeapMemory underneath effectively making this instance an OnHeap collection

Parameters:

bt - byte array tool to manage on-heap memory of this collection

size - array size

structLength - length of struct in bytes, must be >= 8

OffHeapStructArray

private OffHeapStructArray(OffHeapMemory ohm,
                  int structLength)

Private constructor for clone() support

Parameters:

ohm - cloned memory

structLength - struct length

Method Detail

structLength

public int structLength()

Returns length of the single struct in bytes

Specified by:

structLength in interface OffHeapStructCollection

Returns:

length of the single struct in bytes

size

public long size()

Returns number of elements in this array

Specified by:

size in interface OffHeapStructCollection

Returns:

number of elements in this array

free

public void free()

Frees allocated memory, may be called multiple times from any thread

Specified by:

free in interface OffHeapDisposable

iterator

public OffHeapDisposableIterator<byte[]> iterator()

Specified by:

iterator in interface OffHeapDisposableIterable<byte[]>

Specified by:

iterator in interface Iterable<byte[]>

isUnsafe

public boolean isUnsafe()

Whether unsafe implementation of OffHeapMemory is used

Returns:

whether unsafe implementation of OffHeapMemory is used

get

public void get(long index,
       byte[] buffer)

Copies struct on specified index into specified buffer

Specified by:

get in interface OffHeapStructCollection

Parameters:

index - array index

buffer - buffer to copy struct into

get

public void get(long index,
       byte[] buffer,
       int bufferPos)

Copies struct on specified index into specified buffer

Parameters:

index - array index

buffer - buffer to copy struct into

bufferPos - start position in specified buffer

get

public void get(long index,
       int pos,
       byte[] buffer,
       int bufferPos,
       int length)

Copies part of struct on specified index into specified buffer

Specified by:

get in interface OffHeapStructCollection

Parameters:

index - array index

pos - position in struct

buffer - buffer to copy struct into

bufferPos - start position in specified buffer

length - number of bytes to copy

set

public void set(long index,
       byte[] struct)

Copies specified struct contents onto specified index

Specified by:

set in interface OffHeapStructCollection

Parameters:

index - array index

struct - struct to copy into array

set

public void set(long index,
       byte[] struct,
       int structPos)

Copies specified struct contents onto specified index

Parameters:

index - array index

struct - struct to copy into array

structPos - start position in specified struct

getByte

public byte getByte(long index,
           int offset)

Gets byte from struct on specified index with specified offset

Specified by:

getByte in interface OffHeapStructCollection

Parameters:

index - array index

offset - struct offset

Returns:

byte

putByte

public void putByte(long index,
           int offset,
           byte value)

Puts byte into struct onto specified index with specified offset

Specified by:

putByte in interface OffHeapStructCollection

Parameters:

index - array index

offset - struct offset

value - value

getUnsignedByte

public short getUnsignedByte(long index,
                    int offset)

Gets one byte (stored as one signed byte) from struct on specified index with specified offset, converts it to unsigned and returns it as short

Specified by:

getUnsignedByte in interface OffHeapStructCollection

Parameters:

index - array index

offset - struct offset

Returns:

unsigned byte as short

putUnsignedByte

public void putUnsignedByte(long index,
                   int offset,
                   short value)

Puts short with value from 0 to 255 inclusive into struct onto specified index with specified offset as one signed byte

Specified by:

putUnsignedByte in interface OffHeapStructCollection

Parameters:

index - array index

offset - struct offset

value - unsigned byte

getShort

public short getShort(long index,
             int offset)

Gets two bytes as short from struct on specified index with specified offset

Specified by:

getShort in interface OffHeapStructCollection

Parameters:

index - array index

offset - struct offset

Returns:

short value

putShort

public void putShort(long index,
            int offset,
            short value)

Puts short into struct onto specified index with specified offset as two bytes

Specified by:

putShort in interface OffHeapStructCollection

Parameters:

index - array index

offset - struct offset

value - short value

getUnsignedShort

public int getUnsignedShort(long index,
                   int offset)

Gets unsigned short (stored as two bytes) from struct on specified index with specified offset and returns it as int

Specified by:

getUnsignedShort in interface OffHeapStructCollection

Parameters:

index - array index

offset - struct offset

Returns:

unsigned short as int

putUnsignedShort

public void putUnsignedShort(long index,
                    int offset,
                    int value)

Puts int with value from 0 to 65535 inclusive into struct onto specified index with specified offset as two bytes

Specified by:

putUnsignedShort in interface OffHeapStructCollection

Parameters:

index - array index

offset - struct offset

value - unsigned short as int

getInt

public int getInt(long index,
         int offset)

Gets four bytes as int from struct on specified index with specified offset

Specified by:

getInt in interface OffHeapStructCollection

Parameters:

index - array index

offset - struct offset

Returns:

int value

putInt

public void putInt(long index,
          int offset,
          int value)

Puts int into struct onto specified index with specified offset as four bytes

Specified by:

putInt in interface OffHeapStructCollection

Parameters:

index - array index

offset - struct offset

value - int value

getUnsignedInt

public long getUnsignedInt(long index,
                  int offset)

Gets unsigned int (stored as 4 bytes) and returns it as long from struct on specified index with specified offset

Specified by:

getUnsignedInt in interface OffHeapStructCollection

Parameters:

index - array index

offset - struct offset

Returns:

unsigned int as long

putUnsignedInt

public void putUnsignedInt(long index,
                  int offset,
                  long value)

Puts long value from 0 to 4294967295 inclusive into struct onto specified index with specified offset as four bytes

Specified by:

putUnsignedInt in interface OffHeapStructCollection

Parameters:

index - array index

offset - struct offset

value - unsigned int as long

getLong

public long getLong(long index,
           int offset)

Gets long from struct on specified index with specified offset

Specified by:

getLong in interface OffHeapStructCollection

Parameters:

index - array index

offset - struct offset

Returns:

long value

putLong

public void putLong(long index,
           int offset,
           long value)

Puts long into struct onto specified index with specified offset as eight bytes

Specified by:

putLong in interface OffHeapStructCollection

Parameters:

index - array index

offset - struct offset

value - long value

clone

public OffHeapStructArray clone()

Overrides:

clone in class Object

toString

public String toString()

Overrides:

toString in class Object