org.apache.flink.core.memory

Class HeapMemorySegment

java.lang.Object

org.apache.flink.core.memory.MemorySegment

org.apache.flink.core.memory.HeapMemorySegment

@Internal
public final class HeapMemorySegment
extends MemorySegment

This class represents a piece of heap memory managed by Flink. The segment is backed by a byte array and features random put and get methods for the basic types, as well as compare and swap methods.

This class specializes byte access and byte copy calls for heap memory, while reusing the multi-byte type accesses and cross-segment operations from the MemorySegment.

Note that memory segments should usually not be allocated manually, but rather through the MemorySegmentFactory.

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static class	HeapMemorySegment.HeapMemorySegmentFactory A memory segment factory that produces heap memory segments.

Field Summary

Fields

Modifier and Type	Field and Description
static HeapMemorySegment.HeapMemorySegmentFactory	FACTORY

Fields inherited from class org.apache.flink.core.memory.MemorySegment

address, addressLimit, BYTE_ARRAY_BASE_OFFSET, heapMemory, size, UNSAFE

Method Summary

Modifier and Type	Method and Description
void	free() Frees this memory segment.
void	get(DataOutput out, int offset, int length)
byte	get(int index) Reads the byte at the given position.
void	get(int index, byte[] dst) Bulk get method.
void	get(int index, byte[] dst, int offset, int length) Bulk get method.
void	get(int offset, ByteBuffer target, int numBytes) Bulk get method.
byte[]	getArray() Gets the byte array that backs this memory segment.
boolean	getBoolean(int index) Reads one byte at the given position and returns its boolean representation.
void	put(DataInput in, int offset, int length) Bulk put method.
void	put(int index, byte b) Writes the given byte into this buffer at the given position.
void	put(int index, byte[] src) Bulk put method.
void	put(int index, byte[] src, int offset, int length) Bulk put method.
void	put(int offset, ByteBuffer source, int numBytes) Bulk put method.
void	putBoolean(int index, boolean value) Writes one byte containing the byte value into this buffer at the given position.
ByteBuffer	wrap(int offset, int length) Wraps the chunk of the underlying memory located between offset and length in a NIO ByteBuffer.

Methods inherited from class org.apache.flink.core.memory.MemorySegment

compare, copyTo, getAddress, getChar, getCharBigEndian, getCharLittleEndian, getDouble, getDoubleBigEndian, getDoubleLittleEndian, getFloat, getFloatBigEndian, getFloatLittleEndian, getInt, getIntBigEndian, getIntLittleEndian, getLong, getLongBigEndian, getLongLittleEndian, getOwner, getShort, getShortBigEndian, getShortLittleEndian, isFreed, isOffHeap, putChar, putCharBigEndian, putCharLittleEndian, putDouble, putDoubleBigEndian, putDoubleLittleEndian, putFloat, putFloatBigEndian, putFloatLittleEndian, putInt, putIntBigEndian, putIntLittleEndian, putLong, putLongBigEndian, putLongLittleEndian, putShort, putShortBigEndian, putShortLittleEndian, size, swapBytes

Methods inherited from class java.lang.Object

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

Field Detail

FACTORY

public static final HeapMemorySegment.HeapMemorySegmentFactory FACTORY

Method Detail

free

public void free()

Description copied from class: MemorySegment

Frees this memory segment.

After this operation has been called, no further operations are possible on the memory segment and will fail. The actual memory (heap or off-heap) will only be released after this memory segment object has become garbage collected.

Overrides:

free in class MemorySegment

wrap

public ByteBuffer wrap(int offset,
                       int length)

Description copied from class: MemorySegment

Wraps the chunk of the underlying memory located between offset and length in a NIO ByteBuffer.

Specified by:

wrap in class MemorySegment

Parameters:

offset - The offset in the memory segment.

length - The number of bytes to be wrapped as a buffer.

Returns:

A ByteBuffer backed by the specified portion of the memory segment.

getArray

public byte[] getArray()

Gets the byte array that backs this memory segment.

Overrides:

getArray in class MemorySegment

Returns:

The byte array that backs this memory segment, or null, if the segment has been freed.

get

public final byte get(int index)

Description copied from class: MemorySegment

Reads the byte at the given position.

Specified by:

get in class MemorySegment

Parameters:

index - The position from which the byte will be read

Returns:

The byte at the given position.

put

public final void put(int index,
                      byte b)

Description copied from class: MemorySegment

Writes the given byte into this buffer at the given position.

Specified by:

put in class MemorySegment

Parameters:

index - The index at which the byte will be written.

b - The byte value to be written.

get

public final void get(int index,
                      byte[] dst)

Description copied from class: MemorySegment

Bulk get method. Copies dst.length memory from the specified position to the destination memory.

Specified by:

get in class MemorySegment

Parameters:

index - The position at which the first byte will be read.

dst - The memory into which the memory will be copied.

put

public final void put(int index,
                      byte[] src)

Description copied from class: MemorySegment

Bulk put method. Copies src.length memory from the source memory into the memory segment beginning at the specified position.

Specified by:

put in class MemorySegment

Parameters:

index - The index in the memory segment array, where the data is put.

src - The source array to copy the data from.

get

public final void get(int index,
                      byte[] dst,
                      int offset,
                      int length)

Description copied from class: MemorySegment

Bulk get method. Copies length memory from the specified position to the destination memory, beginning at the given offset.

Specified by:

get in class MemorySegment

Parameters:

index - The position at which the first byte will be read.

dst - The memory into which the memory will be copied.

offset - The copying offset in the destination memory.

length - The number of bytes to be copied.

put

public final void put(int index,
                      byte[] src,
                      int offset,
                      int length)

Description copied from class: MemorySegment

Bulk put method. Copies length memory starting at position offset from the source memory into the memory segment starting at the specified index.

Specified by:

put in class MemorySegment

Parameters:

index - The position in the memory segment array, where the data is put.

src - The source array to copy the data from.

offset - The offset in the source array where the copying is started.

length - The number of bytes to copy.

getBoolean

public final boolean getBoolean(int index)

Description copied from class: MemorySegment

Reads one byte at the given position and returns its boolean representation.

Specified by:

getBoolean in class MemorySegment

Parameters:

index - The position from which the memory will be read.

Returns:

The boolean value at the given position.

putBoolean

public final void putBoolean(int index,
                             boolean value)

Description copied from class: MemorySegment

Writes one byte containing the byte value into this buffer at the given position.

Specified by:

putBoolean in class MemorySegment

Parameters:

index - The position at which the memory will be written.

value - The char value to be written.

get

public final void get(DataOutput out,
                      int offset,
                      int length)
               throws IOException

Specified by:

get in class MemorySegment

Throws:

IOException

put

public final void put(DataInput in,
                      int offset,
                      int length)
               throws IOException

Description copied from class: MemorySegment

Bulk put method. Copies length memory from the given DataInput to the memory starting at position offset.

Specified by:

put in class MemorySegment

Parameters:

in - The DataInput to get the data from.

offset - The position in the memory segment to copy the chunk to.

length - The number of bytes to get.

Throws:

IOException - Thrown, if the DataInput encountered a problem upon reading, such as an End-Of-File.

get

public final void get(int offset,
                      ByteBuffer target,
                      int numBytes)

Description copied from class: MemorySegment

Bulk get method. Copies numBytes bytes from this memory segment, starting at position offset to the target ByteBuffer. The bytes will be put into the target buffer starting at the buffer's current position. If this method attempts to write more bytes than the target byte buffer has remaining (with respect to Buffer.remaining()), this method will cause a BufferOverflowException.

Specified by:

get in class MemorySegment

Parameters:

offset - The position where the bytes are started to be read from in this memory segment.

target - The ByteBuffer to copy the bytes to.

numBytes - The number of bytes to copy.

put

public final void put(int offset,
                      ByteBuffer source,
                      int numBytes)

Description copied from class: MemorySegment

Bulk put method. Copies numBytes bytes from the given ByteBuffer, into this memory segment. The bytes will be read from the target buffer starting at the buffer's current position, and will be written to this memory segment starting at offset. If this method attempts to read more bytes than the target byte buffer has remaining (with respect to Buffer.remaining()), this method will cause a BufferUnderflowException.

Specified by:

put in class MemorySegment

Parameters:

offset - The position where the bytes are started to be written to in this memory segment.

source - The ByteBuffer to copy the bytes from.

numBytes - The number of bytes to copy.