com.alexkasko.unsafe.offheapstruct

Class OffHeapStructArrayList

java.lang.Object

com.alexkasko.unsafe.offheapstruct.OffHeapStructArrayList

All Implemented Interfaces:

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

public class OffHeapStructArrayList
extends Object
implements OffHeapStructCollection, OffHeapDisposable

Implementation of off-heap array list 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 ByteArrayTool	bt
private long	capacity
private static int	MIN_CAPACITY_INCREMENT
private OffHeapMemory	ohm
private long	size
private int	structLength

Constructor Summary

Constructors

Constructor and Description
OffHeapStructArrayList(ByteArrayTool bt, int capacity, int structLength) Constructor, uses OnHeapMemory underneath effectively making this instance an OnHeap collection
OffHeapStructArrayList(int structLength) Constructor with default capacity = 12
OffHeapStructArrayList(long capacity, int structLength) Constructor

Method Summary

Methods

Modifier and Type	Method and Description
void	add(byte[] struct) Adds element to the end of this list.
void	add(byte[] struct, int structPos) Adds element to the end of this list.
long	capacity() Returns max number of possible elements in this list without memory reallocation
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	reset() Resets the collection setting size to 0.
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
void	shrinkToFit() Shrinks array list capacity to current size
long	size() Returns number of elements in this list
int	structLength() Returns length of the single struct in bytes
String	toString()

Methods inherited from class java.lang.Object

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

Field Detail

MIN_CAPACITY_INCREMENT

private static final int MIN_CAPACITY_INCREMENT

See Also:

Constant Field Values

bt

private final ByteArrayTool bt

structLength

private final int structLength

ohm

private OffHeapMemory ohm

size

private long size

capacity

private long capacity

Constructor Detail

OffHeapStructArrayList

public OffHeapStructArrayList(int structLength)

Constructor with default capacity = 12

Parameters:

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

OffHeapStructArrayList

public OffHeapStructArrayList(long capacity,
                      int structLength)

Constructor

Parameters:

capacity - initial capacity for this list

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

OffHeapStructArrayList

public OffHeapStructArrayList(ByteArrayTool bt,
                      int capacity,
                      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

capacity - initial capacity for this list

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

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 list

Specified by:

size in interface OffHeapStructCollection

Returns:

number of elements in this list

capacity

public long capacity()

Returns max number of possible elements in this list without memory reallocation

Returns:

max number of possible elements in this list without memory reallocation

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

add

public void add(byte[] struct)

Adds element to the end of this list. Memory area will be allocated another time and copied on capacity exceed.

Parameters:

struct - to add

add

public void add(byte[] struct,
       int structPos)

Adds element to the end of this list. Memory area will be allocated another time and copied on capacity exceed.

Parameters:

struct - struct to add

structPos - struct offset

reset

public void reset()

Resets the collection setting size to 0. Actual memory contents stays untouched.

shrinkToFit

public void shrinkToFit()

Shrinks array list capacity to current size

toString

public String toString()

Overrides:

toString in class Object