io.netty.handler.codec.http2

Class DefaultHttp2LocalFlowController

java.lang.Object

io.netty.handler.codec.http2.DefaultHttp2LocalFlowController

All Implemented Interfaces:

Http2FlowController, Http2LocalFlowController

public class DefaultHttp2LocalFlowController
extends Object
implements Http2LocalFlowController

Basic implementation of Http2LocalFlowController.

Field Summary

Fields

Modifier and Type	Field and Description
static float	DEFAULT_WINDOW_UPDATE_RATIO The default ratio of window size to initial window size below which a WINDOW_UPDATE is sent to expand the window.

Constructor Summary

Constructors

Constructor and Description
DefaultHttp2LocalFlowController(Http2Connection connection, Http2FrameWriter frameWriter)
DefaultHttp2LocalFlowController(Http2Connection connection, Http2FrameWriter frameWriter, float windowUpdateRatio)

Method Summary

Methods

Modifier and Type	Method and Description
void	consumeBytes(ChannelHandlerContext ctx, Http2Stream stream, int numBytes) Indicates that the application has consumed a number of bytes for the given stream and is therefore ready to receive more data from the remote endpoint.
void	incrementWindowSize(ChannelHandlerContext ctx, Http2Stream stream, int delta) Increments the size of the stream's flow control window by the given delta.
int	initialWindowSize() Gets the initial flow control window size that is used as the basis for new stream flow control windows.
void	initialWindowSize(int newWindowSize) Sets the initial flow control window and updates all stream windows (but not the connection window) by the delta.
void	receiveFlowControlledFrame(ChannelHandlerContext ctx, Http2Stream stream, ByteBuf data, int padding, boolean endOfStream) Receives an inbound DATA frame from the remote endpoint and applies flow control policies to it for both the stream as well as the connection.
int	unconsumedBytes(Http2Stream stream) The number of bytes for the given stream that have been received but not yet consumed by the application.
int	windowSize(Http2Stream stream) Gets the number of bytes remaining in the flow control window size for the given stream.
float	windowUpdateRatio() The window update ratio is used to determine when a window update must be sent.
void	windowUpdateRatio(ChannelHandlerContext ctx, Http2Stream stream, float ratio) The window update ratio is used to determine when a window update must be sent.
void	windowUpdateRatio(float ratio) The window update ratio is used to determine when a window update must be sent.
float	windowUpdateRatio(Http2Stream stream) The window update ratio is used to determine when a window update must be sent.

Methods inherited from class java.lang.Object

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

Field Detail

DEFAULT_WINDOW_UPDATE_RATIO

public static final float DEFAULT_WINDOW_UPDATE_RATIO

The default ratio of window size to initial window size below which a WINDOW_UPDATE is sent to expand the window.

See Also:

Constant Field Values

Constructor Detail

DefaultHttp2LocalFlowController

public DefaultHttp2LocalFlowController(Http2Connection connection,
                               Http2FrameWriter frameWriter)

DefaultHttp2LocalFlowController

public DefaultHttp2LocalFlowController(Http2Connection connection,
                               Http2FrameWriter frameWriter,
                               float windowUpdateRatio)

Method Detail

initialWindowSize

public void initialWindowSize(int newWindowSize)
                       throws Http2Exception

Description copied from interface: Http2FlowController

Sets the initial flow control window and updates all stream windows (but not the connection window) by the delta.

This method is used to apply the SETTINGS_INITIAL_WINDOW_SIZE value for an SETTINGS frame.

Specified by:

initialWindowSize in interface Http2FlowController

Parameters:

newWindowSize - the new initial window size.

Throws:

Http2Exception - thrown if any protocol-related error occurred.

initialWindowSize

public int initialWindowSize()

Description copied from interface: Http2FlowController

Gets the initial flow control window size that is used as the basis for new stream flow control windows.

Specified by:

initialWindowSize in interface Http2FlowController

windowSize

public int windowSize(Http2Stream stream)

Description copied from interface: Http2FlowController

Gets the number of bytes remaining in the flow control window size for the given stream.

Specified by:

windowSize in interface Http2FlowController

Parameters:

stream - The subject stream. Use Http2Connection.connectionStream() for requesting the size of the connection window.

Returns:

the current size of the flow control window.

incrementWindowSize

public void incrementWindowSize(ChannelHandlerContext ctx,
                       Http2Stream stream,
                       int delta)
                         throws Http2Exception

Description copied from interface: Http2FlowController

Increments the size of the stream's flow control window by the given delta.

In the case of a Http2RemoteFlowController this is called upon receipt of a WINDOW_UPDATE frame from the remote endpoint to mirror the changes to the window size.

For a Http2LocalFlowController this can be called to request the expansion of the window size published by this endpoint. It is up to the implementation, however, as to when a WINDOW_UPDATE is actually sent.

Specified by:

incrementWindowSize in interface Http2FlowController

Parameters:

ctx - The context for the calling handler

stream - The subject stream. Use Http2Connection.connectionStream() for requesting the size of the connection window.

delta - the change in size of the flow control window.

Throws:

Http2Exception - thrown if a protocol-related error occurred.

consumeBytes

public void consumeBytes(ChannelHandlerContext ctx,
                Http2Stream stream,
                int numBytes)
                  throws Http2Exception

Description copied from interface: Http2LocalFlowController

Indicates that the application has consumed a number of bytes for the given stream and is therefore ready to receive more data from the remote endpoint. The application must consume any bytes that it receives or the flow control window will collapse. Consuming bytes enables the flow controller to send WINDOW_UPDATE to restore a portion of the flow control window for the stream.

Specified by:

consumeBytes in interface Http2LocalFlowController

Parameters:

ctx - the channel handler context to use when sending a WINDOW_UPDATE if appropriate

stream - the stream for which window space should be freed. The connection stream object must not be used.

numBytes - the number of bytes to be returned to the flow control window.

Throws:

Http2Exception - if the number of bytes returned exceeds the Http2LocalFlowController.unconsumedBytes(io.netty.handler.codec.http2.Http2Stream) for the stream.

unconsumedBytes

public int unconsumedBytes(Http2Stream stream)

Description copied from interface: Http2LocalFlowController

The number of bytes for the given stream that have been received but not yet consumed by the application.

Specified by:

unconsumedBytes in interface Http2LocalFlowController

Parameters:

stream - the stream for which window space should be freed.

Returns:

the number of unconsumed bytes for the stream.

windowUpdateRatio

public void windowUpdateRatio(float ratio)

The window update ratio is used to determine when a window update must be sent. If the ratio of bytes processed since the last update has meet or exceeded this ratio then a window update will be sent. This is the global window update ratio that will be used for new streams.

Parameters:

ratio - the ratio to use when checking if a WINDOW_UPDATE is determined necessary for new streams.

Throws:

IllegalArgumentException - If the ratio is out of bounds (0, 1).

windowUpdateRatio

public float windowUpdateRatio()

The window update ratio is used to determine when a window update must be sent. If the ratio of bytes processed since the last update has meet or exceeded this ratio then a window update will be sent. This is the global window update ratio that will be used for new streams.

windowUpdateRatio

public void windowUpdateRatio(ChannelHandlerContext ctx,
                     Http2Stream stream,
                     float ratio)
                       throws Http2Exception

The window update ratio is used to determine when a window update must be sent. If the ratio of bytes processed since the last update has meet or exceeded this ratio then a window update will be sent. This window update ratio will only be applied to streamId.

Note it is the responsibly of the caller to ensure that the the initial SETTINGS frame is sent before this is called. It would be considered a Http2Error.PROTOCOL_ERROR if a WINDOW_UPDATE was generated by this method before the initial SETTINGS frame is sent.

Parameters:

ctx - the context to use if a WINDOW_UPDATE is determined necessary.

stream - the stream for which ratio applies to.

ratio - the ratio to use when checking if a WINDOW_UPDATE is determined necessary.

Throws:

Http2Exception - If a protocol-error occurs while generating WINDOW_UPDATE frames

windowUpdateRatio

public float windowUpdateRatio(Http2Stream stream)
                        throws Http2Exception

The window update ratio is used to determine when a window update must be sent. If the ratio of bytes processed since the last update has meet or exceeded this ratio then a window update will be sent. This window update ratio will only be applied to streamId.

Throws:

Http2Exception - If no stream corresponding to stream could be found.

receiveFlowControlledFrame

public void receiveFlowControlledFrame(ChannelHandlerContext ctx,
                              Http2Stream stream,
                              ByteBuf data,
                              int padding,
                              boolean endOfStream)
                                throws Http2Exception

Description copied from interface: Http2LocalFlowController

Receives an inbound DATA frame from the remote endpoint and applies flow control policies to it for both the stream as well as the connection. If any flow control policies have been violated, an exception is raised immediately, otherwise the frame is considered to have "passed" flow control.

Specified by:

receiveFlowControlledFrame in interface Http2LocalFlowController

Parameters:

ctx - the context from the handler where the frame was read.

stream - the subject stream for the received frame. The connection stream object must not be used.

data - payload buffer for the frame.

padding - the number of padding bytes found at the end of the frame.

endOfStream - Indicates whether this is the last frame to be sent from the remote endpoint for this stream.

Throws:

Http2Exception - if any flow control errors are encountered.