Module io.helidon.webserver

Package io.helidon.webserver

Class ByteBufDataChunk

java.lang.Object

io.helidon.webserver.ByteBufDataChunk

All Implemented Interfaces:

DataChunk, Iterable<ByteBuffer>

public class ByteBufDataChunk
extends Object
implements DataChunk

A special DataChunk implementation based on Netty's buffers. This is used by our Jersey SPI implementation to take advantage of Netty's buffer pooling.

Method Summary

Modifier and Type	Method	Description
byte[]	bytes()	Gets the content of the underlying byte buffers as an array of bytes.
static ByteBufDataChunk	create(boolean flush, boolean readOnly, io.netty.buffer.ByteBuf... byteBufs)	Creates an instance given an array of ByteBuf's.
static ByteBufDataChunk	create(boolean flush, boolean readOnly, Runnable releaseCallback, io.netty.buffer.ByteBuf... byteBufs)	Creates an instance given an array of ByteBuf's.
ByteBuffer[]	data()	This method is needed for testing some of our examples.
<T> T[]	data(Class<T> clazz)	Returns a representation of this chunk as an array of T's.
DataChunk	duplicate()	Makes a copy of this data chunk including its underlying ByteBuffer.
boolean	flush()	Returns true if all caches are requested to flush when this chunk is written.
<T> boolean	isBackedBy(Class<T> clazz)	Checks if this instance is backed by buffers of a certain kind.
boolean	isReadOnly()	Returns true if the underlying byte buffer of this chunk is read only or false otherwise.
boolean	isReleased()	Whether this chunk is released and the associated data structures returned by methods (such as DataChunk.iterator() or DataChunk.bytes()) should not be used.
Iterator<ByteBuffer>	iterator()
void	release()	Releases this chunk.
int	remaining()	Returns the sum of elements between the current position and the limit of each of the underlying ByteBuffer.
Optional<CompletableFuture<DataChunk>>	writeFuture()	Returns a write future associated with this chunk.
void	writeFuture(CompletableFuture<DataChunk> writeFuture)	Set a write future that will complete when data chunk has been written to a connection.

Methods inherited from class java.lang.Object

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

Methods inherited from interface io.helidon.common.http.DataChunk

id, isFlushChunk

Methods inherited from interface java.lang.Iterable

forEach, spliterator

Method Detail

create

public static ByteBufDataChunk create(boolean flush,
                                      boolean readOnly,
                                      io.netty.buffer.ByteBuf... byteBufs)

Creates an instance given an array of ByteBuf's.

Parameters:

flush - a signal that this chunk should be written and flushed from any cache if possible

readOnly - marks this buffer as read only

byteBufs - the data for this chunk. Should not be reused until releaseCallback is used

Returns:

new chunk

create

public static ByteBufDataChunk create(boolean flush,
                                      boolean readOnly,
                                      Runnable releaseCallback,
                                      io.netty.buffer.ByteBuf... byteBufs)

Creates an instance given an array of ByteBuf's.

Parameters:

flush - a signal that this chunk should be written and flushed from any cache if possible

readOnly - marks this buffer as read only

releaseCallback - a callback which is called when this chunk is completely processed

byteBufs - the data for this chunk. Should not be reused until releaseCallback is used

Returns:

new chunk

isBackedBy

public <T> boolean isBackedBy(Class<T> clazz)

Description copied from interface: DataChunk

Checks if this instance is backed by buffers of a certain kind.

Specified by:

isBackedBy in interface DataChunk

Type Parameters:

T - the buffer type

Parameters:

clazz - a buffer class instance

Returns:

outcome of test

data

public <T> T[] data(Class<T> clazz)

Description copied from interface: DataChunk

Returns a representation of this chunk as an array of T's.

Specified by:

data in interface DataChunk

Type Parameters:

T - the buffer type

Parameters:

clazz - class of return type

Returns:

an array of T's

isReleased

public boolean isReleased()

Description copied from interface: DataChunk

Whether this chunk is released and the associated data structures returned by methods (such as DataChunk.iterator() or DataChunk.bytes()) should not be used. The implementations may choose to not implement this optimization and to never mutate the underlying memory; in such case this method does no-op.

Note that the methods of this instance are expected to be called by a single thread; if not, external synchronization must be used.

Specified by:

isReleased in interface DataChunk

Returns:

whether this chunk has been released, defaults to false

flush

public boolean flush()

Description copied from interface: DataChunk

Returns true if all caches are requested to flush when this chunk is written. This method is only meaningful when handing data over to Helidon APIs (e.g. for server response and client requests).

Specified by:

flush in interface DataChunk

Returns:

true if it is requested to flush all caches after this chunk is written, defaults to false.

isReadOnly

public boolean isReadOnly()

Description copied from interface: DataChunk

Returns true if the underlying byte buffer of this chunk is read only or false otherwise.

Specified by:

isReadOnly in interface DataChunk

Returns:

Immutability outcome.

release

public void release()

Description copied from interface: DataChunk

Releases this chunk. The underlying data as well as the data structure instances returned by methods DataChunk.bytes() and DataChunk.iterator() may become stale and should not be used anymore. The implementations may choose to not implement this optimization and to never mutate the underlying memory; in such case this method does no-op.

Note that the methods of this instance are expected to be called by a single thread; if not, external synchronization must be used.

Specified by:

release in interface DataChunk

writeFuture

public void writeFuture(CompletableFuture<DataChunk> writeFuture)

Description copied from interface: DataChunk

Set a write future that will complete when data chunk has been written to a connection.

Specified by:

writeFuture in interface DataChunk

Parameters:

writeFuture - Write future.

writeFuture

public Optional<CompletableFuture<DataChunk>> writeFuture()

Description copied from interface: DataChunk

Returns a write future associated with this chunk.

Specified by:

writeFuture in interface DataChunk

Returns:

Write future if one has ben set.

remaining

public int remaining()

Description copied from interface: DataChunk

Returns the sum of elements between the current position and the limit of each of the underlying ByteBuffer.

Specified by:

remaining in interface DataChunk

Returns:

The number of elements remaining in all underlying buffers

data

public ByteBuffer[] data()

This method is needed for testing some of our examples. It bypasses the optimization for which this class was created.

Specified by:

data in interface DataChunk

Returns:

array of ByteBuffer

duplicate

public DataChunk duplicate()

Description copied from interface: DataChunk

Makes a copy of this data chunk including its underlying ByteBuffer. This may be necessary for caching in case ByteBuffer.rewind() is called to reuse a byte buffer. Note that only the actual bytes used in the data chunk are copied, the resulting data chunk's capacity may be less than the original.

Specified by:

duplicate in interface DataChunk

Returns:

A copy of this data chunk.

bytes

public byte[] bytes()

Description copied from interface: DataChunk

Gets the content of the underlying byte buffers as an array of bytes. The returned array contains only the part of data that wasn't read yet. Calling this method doesn't cause the underlying byte buffers to be read.

It is expected the returned byte array holds a reference to data that will become stale upon calling method DataChunk.release(). (For instance, the memory segment is pooled by the underlying TCP server and is reused for a subsequent request chunk.) The idea behind this class is to be able to minimize data copying; ideally, in order to achieve the best performance, to not copy them at all. However, the implementations may choose otherwise.

Note that the methods of this instance are expected to be called by a single thread; if not, external synchronization must be used.

Specified by:

bytes in interface DataChunk

Returns:

an array of bytes that is guarantied to stay immutable as long as method DataChunk.release() is not called

iterator

public Iterator<ByteBuffer> iterator()

Specified by:

iterator in interface DataChunk

Specified by:

iterator in interface Iterable<ByteBuffer>