Buffer (Flink : 1.17-SNAPSHOT API)

All Known Implementing Classes:

CompositeBuffer, FileRegionBuffer, NetworkBuffer, ReadOnlySlicedNetworkBuffer
```
public interface Buffer
```
Wrapper for pooled MemorySegment instances with reference counting.
This is similar to Netty's ByteBuf with some extensions and restricted to the methods our use cases outside Netty handling use. In particular, we use two different indexes for read and write operations, i.e. the reader and writer index (size of written data), which specify three regions inside the memory segment:
```
     +-------------------+----------------+----------------+
     | discardable bytes | readable bytes | writable bytes |
     +-------------------+----------------+----------------+
     |                   |                |                |
     0      <=      readerIndex  <=  writerIndex   <=  max capacity
 
```
Our non-Netty usages of this Buffer class either rely on the underlying getMemorySegment() directly, or on ByteBuffer wrappers of this buffer which do not modify either index, so the indices need to be updated manually via setReaderIndex(int) and setSize(int).

Nested Class Summary

Nested Classes
Modifier and Type	Interface and Description
`static class`	`Buffer.DataType` Used to identify the type of data contained in the `Buffer` so that we can get the information without deserializing the serialized data.

Method Summary

All Methods Instance Methods Abstract Methods Default Methods Deprecated Methods
Modifier and Type	Method and Description
`org.apache.flink.shaded.netty4.io.netty.buffer.ByteBuf`	`asByteBuf()`
`Buffer.DataType`	`getDataType()` Gets the type of data this buffer represents.
`int`	`getMaxCapacity()` Returns the maximum size of the buffer, i.e.
`MemorySegment`	`getMemorySegment()` Deprecated.
`int`	`getMemorySegmentOffset()` Deprecated.
`ByteBuffer`	`getNioBuffer(int index, int length)` Gets a new `ByteBuffer` instance wrapping this buffer's bytes.
`ByteBuffer`	`getNioBufferReadable()` Gets a new `ByteBuffer` instance wrapping this buffer's readable bytes, i.e.
`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.
`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 `getSize() - getReaderIndex()`).
`Buffer`	`readOnlySlice()` Returns a read-only slice of this buffer's readable bytes, i.e.
`Buffer`	`readOnlySlice(int index, int length)` Returns a read-only slice of this buffer.
`void`	`recycleBuffer()` Releases this buffer once, i.e.
`int`	`refCnt()` The current reference counter.
`Buffer`	`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`	`setSize(int writerIndex)` Sets the size of the written data, i.e.
`default String`	`toDebugString(boolean includeHash)`

- Method Detail
  - isBuffer
```
boolean isBuffer()
```
    Returns whether this buffer represents a buffer or an event.
    
    Returns:
    
    true if this is a real buffer, false if this is an event
  - getMemorySegment
```
@Deprecated
MemorySegment getMemorySegment()
```
    Deprecated.
    
    Returns the underlying memory segment. This method is dangerous since it ignores read only protections and omits slices. Use it only along the getMemorySegmentOffset().
    This method will be removed in the future. For writing use BufferBuilder.
    
    Returns:
    
    the memory segment backing this buffer
  - getMemorySegmentOffset
```
@Deprecated
int getMemorySegmentOffset()
```
    Deprecated.
    
    This method will be removed in the future. For writing use BufferBuilder.
    
    Returns:
    
    the offset where this (potential slice) Buffer's data start in the underlying memory segment.
  - getRecycler
```
BufferRecycler getRecycler()
```
    Gets the buffer's recycler.
    
    Returns:
    
    buffer recycler
  - recycleBuffer
```
void recycleBuffer()
```
    Releases this buffer once, i.e. reduces the reference count and recycles the buffer if the reference count reaches 0.
    
    See Also:
    
    retainBuffer()
  - isRecycled
```
boolean isRecycled()
```
    Returns whether this buffer has been recycled or not.
    
    Returns:
    
    true if already recycled, false otherwise
  - retainBuffer
```
Buffer retainBuffer()
```
    Retains this buffer for further use, increasing the reference counter by 1.
    
    Returns:
    
    this instance (for chained calls)
    
    See Also:
    
    recycleBuffer()
  - readOnlySlice
```
Buffer readOnlySlice()
```
    Returns a read-only slice of this buffer's readable bytes, i.e. between getReaderIndex() and getSize().
    Reader and writer indices as well as markers are not shared. Reference counters are shared but the slice is not retained automatically.
    
    Returns:
    
    a read-only sliced buffer
  - readOnlySlice
```
Buffer readOnlySlice(int index,
                     int length)
```
    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.
    
    Parameters:
    
    index - the index to start from
    
    length - the length of the slice
    
    Returns:
    
    a read-only sliced buffer
  - getMaxCapacity
```
int getMaxCapacity()
```
    Returns the maximum size of the buffer, i.e. the capacity of the underlying MemorySegment.
    
    Returns:
    
    size of the buffer
  - getReaderIndex
```
int getReaderIndex()
```
    Returns the reader index of this buffer.
    This is where readable (unconsumed) bytes start in the backing memory segment.
    
    Returns:
    
    reader index (from 0 (inclusive) to the size of the backing MemorySegment (inclusive))
  - setReaderIndex
```
void setReaderIndex(int readerIndex)
             throws IndexOutOfBoundsException
```
    Sets the reader index of this buffer.
    
    Throws:
    
    IndexOutOfBoundsException - if the index is less than 0 or greater than getSize()
  - getSize
```
int getSize()
```
    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.
    
    Returns:
    
    writer index (from 0 (inclusive) to the size of the backing MemorySegment (inclusive))
  - setSize
```
void setSize(int writerIndex)
```
    Sets the size of the written data, i.e. the writer index, of this buffer.
    
    Throws:
    
    IndexOutOfBoundsException - if the index is less than getReaderIndex() or greater than getMaxCapacity()
  - readableBytes
```
int readableBytes()
```
    Returns the number of readable bytes (same as getSize() - getReaderIndex()).
  - getNioBufferReadable
```
ByteBuffer getNioBufferReadable()
```
    Gets a new ByteBuffer instance wrapping this buffer's readable bytes, i.e. between getReaderIndex() and getSize().
    Please note that neither index is updated by the returned buffer.
    
    Returns:
    
    byte buffer sharing the contents of the underlying memory segment
  - getNioBuffer
```
ByteBuffer getNioBuffer(int index,
                        int length)
                 throws IndexOutOfBoundsException
```
    Gets a new ByteBuffer instance wrapping this buffer's bytes.
    Please note that neither read nor write index are updated by the returned 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:
    
    getNioBufferReadable()
  - setAllocator
```
void setAllocator(org.apache.flink.shaded.netty4.io.netty.buffer.ByteBufAllocator allocator)
```
    Sets the buffer allocator for use in netty.
    
    Parameters:
    
    allocator - netty buffer allocator
  - asByteBuf
```
org.apache.flink.shaded.netty4.io.netty.buffer.ByteBuf asByteBuf()
```
    Returns:
    
    self as ByteBuf implementation.
  - isCompressed
```
boolean isCompressed()
```
    Returns:
    
    whether the buffer is compressed or not.
  - setCompressed
```
void setCompressed(boolean isCompressed)
```
    Tags the buffer as compressed or uncompressed.
  - getDataType
```
Buffer.DataType getDataType()
```
    Gets the type of data this buffer represents.
  - setDataType
```
void setDataType(Buffer.DataType dataType)
```
    Sets the type of data this buffer represents.
  - refCnt
```
int refCnt()
```
    The current reference counter. Increased by retainBuffer() and decreased with recycleBuffer().
  - toDebugString
```
default String toDebugString(boolean includeHash)
```

Back to Flink Website

Interface Buffer

Nested Class Summary

Method Summary

Method Detail

isBuffer

getMemorySegment

getMemorySegmentOffset

getRecycler

recycleBuffer

isRecycled

retainBuffer

readOnlySlice

readOnlySlice

getMaxCapacity

getReaderIndex

setReaderIndex

getSize

setSize

readableBytes

getNioBufferReadable

getNioBuffer

setAllocator

asByteBuf

isCompressed

setCompressed

getDataType

setDataType

refCnt

toDebugString

Back to Flink Website