org.apache.flink.runtime.io.network.buffer

Class FileRegionBuffer

java.lang.Object

org.apache.flink.shaded.netty4.io.netty.util.AbstractReferenceCounted

org.apache.flink.shaded.netty4.io.netty.channel.DefaultFileRegion

org.apache.flink.runtime.io.network.buffer.FileRegionBuffer

All Implemented Interfaces:

Buffer, org.apache.flink.shaded.netty4.io.netty.channel.FileRegion, org.apache.flink.shaded.netty4.io.netty.util.ReferenceCounted

public class FileRegionBuffer
extends org.apache.flink.shaded.netty4.io.netty.channel.DefaultFileRegion
implements Buffer

This class represents a chunk of data in a file channel. Its purpose is to be passed to the netty code and to be written to the socket via the zero-copy direct transfer capabilities of FileChannel.transferTo(long, long, WritableByteChannel).

This class implements Buffer mainly for compatible with existing usages. It can be thought of as a "lazy buffer" that does not hold the data directly, although the data can be fetches as a read-only ByteBuffer when needed, for example in local input channels. See readInto(MemorySegment) and getNioBufferReadable(). Because this buffer is read-only, the modification methods (and methods that give a writable buffer) throw UnsupportedOperationException.

This class extends from Netty's DefaultFileRegion, similar as the NetworkBuffer extends from Netty's ByteBuf. That way we can pass both of them to Netty in the same way, and Netty will internally treat them appropriately.

Nested Class Summary

Nested classes/interfaces inherited from interface org.apache.flink.runtime.io.network.buffer.Buffer

Buffer.DataType

Constructor Summary

Constructors

Constructor and Description
FileRegionBuffer(FileChannel fileChannel, long fileChannelPosition, int bufferSize, Buffer.DataType dataType, boolean isCompressed)

Method Summary

Modifier and Type	Method and Description
org.apache.flink.shaded.netty4.io.netty.buffer.ByteBuf	asByteBuf()
void	deallocate()
Buffer.DataType	getDataType() Gets the type of data this buffer represents.
int	getMaxCapacity() Returns the maximum size of the buffer, i.e. the capacity of the underlying MemorySegment.
MemorySegment	getMemorySegment() Returns the underlying memory segment.
int	getMemorySegmentOffset() This method will be removed in the future.
ByteBuffer	getNioBuffer(int index, int length) Gets a new ByteBuffer instance wrapping this buffer's bytes.
ByteBuffer	getNioBufferReadable() This method is only called by tests and by event-deserialization, like checkpoint barriers.
int	getReaderIndex() Returns the reader index of this buffer.
BufferRecycler	getRecycler() Gets the buffer's recycler.
int	getSize() Returns the size of the written data, i.e. the writer index, of this buffer.
boolean	isBuffer() Returns whether this buffer represents a buffer or an event.
boolean	isCompressed()
boolean	isRecycled() Returns whether this buffer has been recycled or not.
int	readableBytes() Returns the number of readable bytes (same as Buffer.getSize() - Buffer.getReaderIndex()).
Buffer	readInto(MemorySegment segment)
ReadOnlySlicedNetworkBuffer	readOnlySlice() Returns a read-only slice of this buffer's readable bytes, i.e. between Buffer.getReaderIndex() and Buffer.getSize().
ReadOnlySlicedNetworkBuffer	readOnlySlice(int index, int length) Returns a read-only slice of this buffer.
void	recycleBuffer() Releases this buffer once, i.e. reduces the reference count and recycles the buffer if the reference count reaches 0.
FileRegionBuffer	retainBuffer() Retains this buffer for further use, increasing the reference counter by 1.
void	setAllocator(org.apache.flink.shaded.netty4.io.netty.buffer.ByteBufAllocator allocator) Sets the buffer allocator for use in netty.
void	setCompressed(boolean isCompressed) Tags the buffer as compressed or uncompressed.
void	setDataType(Buffer.DataType dataType) Sets the type of data this buffer represents.
void	setReaderIndex(int readerIndex) Sets the reader index of this buffer.
void	setRecycler(BufferRecycler bufferRecycler) Sets the buffer's recycler.
void	setSize(int writerIndex) Sets the size of the written data, i.e. the writer index, of this buffer.

Methods inherited from class org.apache.flink.shaded.netty4.io.netty.channel.DefaultFileRegion

count, isOpen, open, position, retain, retain, touch, touch, transfered, transferred, transferTo

Methods inherited from class org.apache.flink.shaded.netty4.io.netty.util.AbstractReferenceCounted

refCnt, release, release, setRefCnt

Methods inherited from class java.lang.Object

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

Methods inherited from interface org.apache.flink.runtime.io.network.buffer.Buffer

refCnt, toDebugString

Methods inherited from interface org.apache.flink.shaded.netty4.io.netty.util.ReferenceCounted

refCnt, release, release

Constructor Detail

FileRegionBuffer

public FileRegionBuffer(FileChannel fileChannel,
                        long fileChannelPosition,
                        int bufferSize,
                        Buffer.DataType dataType,
                        boolean isCompressed)

Method Detail

isBuffer

public boolean isBuffer()

Description copied from interface: Buffer

Returns whether this buffer represents a buffer or an event.

Specified by:

isBuffer in interface Buffer

Returns:

true if this is a real buffer, false if this is an event

getMemorySegment

public MemorySegment getMemorySegment()

Description copied from interface: Buffer

Returns the underlying memory segment. This method is dangerous since it ignores read only protections and omits slices. Use it only along the Buffer.getMemorySegmentOffset().

This method will be removed in the future. For writing use BufferBuilder.

Specified by:

getMemorySegment in interface Buffer

Returns:

the memory segment backing this buffer

getMemorySegmentOffset

public int getMemorySegmentOffset()

Description copied from interface: Buffer

This method will be removed in the future. For writing use BufferBuilder.

Specified by:

getMemorySegmentOffset in interface Buffer

Returns:

the offset where this (potential slice) Buffer's data start in the underlying memory segment.

readOnlySlice

public ReadOnlySlicedNetworkBuffer readOnlySlice()

Description copied from interface: Buffer

Returns a read-only slice of this buffer's readable bytes, i.e. between Buffer.getReaderIndex() and Buffer.getSize().

Reader and writer indices as well as markers are not shared. Reference counters are shared but the slice is not retained automatically.

Specified by:

readOnlySlice in interface Buffer

Returns:

a read-only sliced buffer

readOnlySlice

public ReadOnlySlicedNetworkBuffer readOnlySlice(int index,
                                                 int length)

Description copied from interface: Buffer

Returns a read-only slice of this buffer.

Reader and writer indices as well as markers are not shared. Reference counters are shared but the slice is not retained automatically.

Specified by:

readOnlySlice in interface Buffer

Parameters:

index - the index to start from

length - the length of the slice

Returns:

a read-only sliced buffer

getMaxCapacity

public int getMaxCapacity()

Description copied from interface: Buffer

Returns the maximum size of the buffer, i.e. the capacity of the underlying MemorySegment.

Specified by:

getMaxCapacity in interface Buffer

Returns:

size of the buffer

getReaderIndex

public int getReaderIndex()

Description copied from interface: Buffer

Returns the reader index of this buffer.

This is where readable (unconsumed) bytes start in the backing memory segment.

Specified by:

getReaderIndex in interface Buffer

Returns:

reader index (from 0 (inclusive) to the size of the backing MemorySegment (inclusive))

setReaderIndex

public void setReaderIndex(int readerIndex)
                    throws IndexOutOfBoundsException

Description copied from interface: Buffer

Sets the reader index of this buffer.

Specified by:

setReaderIndex in interface Buffer

Throws:

IndexOutOfBoundsException - if the index is less than 0 or greater than Buffer.getSize()

getNioBufferReadable

public ByteBuffer getNioBufferReadable()

This method is only called by tests and by event-deserialization, like checkpoint barriers. Because such events are not used for bounded intermediate results, this method currently executes only in tests.

Specified by:

getNioBufferReadable in interface Buffer

Returns:

byte buffer sharing the contents of the underlying memory segment

getNioBuffer

public ByteBuffer getNioBuffer(int index,
                               int length)
                        throws IndexOutOfBoundsException

Description copied from interface: Buffer

Gets a new ByteBuffer instance wrapping this buffer's bytes.

Please note that neither read nor write index are updated by the returned buffer.

Specified by:

getNioBuffer in interface Buffer

Returns:

byte buffer sharing the contents of the underlying memory segment

Throws:

IndexOutOfBoundsException - if the indexes are not without the buffer's bounds

See Also:

Buffer.getNioBufferReadable()

asByteBuf

public org.apache.flink.shaded.netty4.io.netty.buffer.ByteBuf asByteBuf()

Specified by:

asByteBuf in interface Buffer

Returns:

self as ByteBuf implementation.

setSize

public void setSize(int writerIndex)

Description copied from interface: Buffer

Sets the size of the written data, i.e. the writer index, of this buffer.

Specified by:

setSize in interface Buffer

getSize

public int getSize()

Description copied from interface: Buffer

Returns the size of the written data, i.e. the writer index, of this buffer.

This is where writable bytes start in the backing memory segment.

Specified by:

getSize in interface Buffer

Returns:

writer index (from 0 (inclusive) to the size of the backing MemorySegment (inclusive))

readableBytes

public int readableBytes()

Description copied from interface: Buffer

Returns the number of readable bytes (same as Buffer.getSize() - Buffer.getReaderIndex()).

Specified by:

readableBytes in interface Buffer

setAllocator

public void setAllocator(org.apache.flink.shaded.netty4.io.netty.buffer.ByteBufAllocator allocator)

Description copied from interface: Buffer

Sets the buffer allocator for use in netty.

Specified by:

setAllocator in interface Buffer

Parameters:

allocator - netty buffer allocator

getRecycler

public BufferRecycler getRecycler()

Description copied from interface: Buffer

Gets the buffer's recycler.

Specified by:

getRecycler in interface Buffer

Returns:

buffer recycler

setRecycler

public void setRecycler(BufferRecycler bufferRecycler)

Description copied from interface: Buffer

Sets the buffer's recycler.

Note that updating the recycler is an unsafe operation and this method cannot guarantee thread safety. It is important for the caller to fully understand the consequences of calling this method. Incorrectly updating the buffer recycler can result in a leak of the buffer due to using a wrong recycler to recycle buffer. Therefore, be careful when calling this method.

Specified by:

setRecycler in interface Buffer

Parameters:

bufferRecycler - the new buffer recycler

recycleBuffer

public void recycleBuffer()

Description copied from interface: Buffer

Releases this buffer once, i.e. reduces the reference count and recycles the buffer if the reference count reaches 0.

Specified by:

recycleBuffer in interface Buffer

See Also:

Buffer.retainBuffer()

isRecycled

public boolean isRecycled()

Description copied from interface: Buffer

Returns whether this buffer has been recycled or not.

Specified by:

isRecycled in interface Buffer

Returns:

true if already recycled, false otherwise

retainBuffer

public FileRegionBuffer retainBuffer()

Description copied from interface: Buffer

Retains this buffer for further use, increasing the reference counter by 1.

Specified by:

retainBuffer in interface Buffer

Returns:

this instance (for chained calls)

See Also:

Buffer.recycleBuffer()

isCompressed

public boolean isCompressed()

Specified by:

isCompressed in interface Buffer

Returns:

whether the buffer is compressed or not.

setCompressed

public void setCompressed(boolean isCompressed)

Description copied from interface: Buffer

Tags the buffer as compressed or uncompressed.

Specified by:

setCompressed in interface Buffer

getDataType

public Buffer.DataType getDataType()

Description copied from interface: Buffer

Gets the type of data this buffer represents.

Specified by:

getDataType in interface Buffer

setDataType

public void setDataType(Buffer.DataType dataType)

Description copied from interface: Buffer

Sets the type of data this buffer represents.

Specified by:

setDataType in interface Buffer

deallocate

public void deallocate()

Overrides:

deallocate in class org.apache.flink.shaded.netty4.io.netty.channel.DefaultFileRegion

readInto

public Buffer readInto(MemorySegment segment)
                throws IOException

Throws:

IOException