http://netty.io/netty-all/: Netty is an asynchronous event-driven network application framework for rapid development of maintainable high performance protocol servers and clients. (The Netty Project) 
/*
 * Copyright 2014 The Netty Project
 *
 * The Netty Project licenses this file to you under the Apache License, version 2.0 (the
 * "License"); you may not use this file except in compliance with the License. You may obtain a
 * copy of the License at:
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software distributed under the License
 * is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express
 * or implied. See the License for the specific language governing permissions and limitations under
 * the License.
 */
package io.netty.handler.codec.http2;

import io.netty.buffer.ByteBuf;
import io.netty.util.internal.UnstableApi;


A Http2FlowController for controlling the inbound flow of DATA frames from the remote endpoint. 
/**
 * A {@link Http2FlowController} for controlling the inbound flow of {@code DATA} frames from the remote endpoint.
 */
@UnstableApi
public interface Http2LocalFlowController extends Http2FlowController {
    
Sets the writer to be use for sending WINDOW_UPDATE frames. This must be called before any flow controlled data is received. 
Params:
  • frameWriter – the HTTP/2 frame writer.
/**
     * Sets the writer to be use for sending {@code WINDOW_UPDATE} frames. This must be called before any flow
     * controlled data is received.
     *
     * @param frameWriter the HTTP/2 frame writer.
     */
    Http2LocalFlowController frameWriter(Http2FrameWriter frameWriter);

    
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. 
 If stream is null or closed, flow control should only be applied to the connection window and the bytes are immediately consumed. 
Params:
  • stream – the subject stream for the received frame. The connection stream object must not be used. If 
stream is null or closed, flow control should only be applied to the connection window and the bytes are immediately consumed.
  • data – payload buffer for the frame.
  • padding – additional bytes that should be added to obscure the true content size. Must be between 0 and
               256 (inclusive).
  • endOfStream – Indicates whether this is the last frame to be sent from the remote endpoint for this stream.
Throws:
/**
     * Receives an inbound {@code DATA} frame from the remote endpoint and applies flow control policies to it for both
     * the {@code 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.
     * <p/>
     * If {@code stream} is {@code null} or closed, flow control should only be applied to the connection window and the
     * bytes are immediately consumed.
     *
     * @param stream the subject stream for the received frame. The connection stream object must not be used. If {@code
     * stream} is {@code null} or closed, flow control should only be applied to the connection window and the bytes are
     * immediately consumed.
     * @param data payload buffer for the frame.
     * @param padding additional bytes that should be added to obscure the true content size. Must be between 0 and
     *                256 (inclusive).
     * @param 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.
     */
    void receiveFlowControlledFrame(Http2Stream stream, ByteBuf data, int padding,
                                    boolean endOfStream) throws Http2Exception;

    
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. 
 If stream is null or closed (i.e. Http2Stream.state() method returns State.CLOSED), calling this method has no effect. 
Params:
  • stream – the stream for which window space should be freed. The connection stream object must not be used. If stream is null or closed (i.e. Http2Stream.state() method returns State.CLOSED), calling this method has no effect.
  • numBytes – the number of bytes to be returned to the flow control window.
Throws:
Returns:true if a WINDOW_UPDATE was sent, false otherwise.
/**
     * 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 {@code WINDOW_UPDATE} to
     * restore a portion of the flow control window for the stream.
     * <p/>
     * If {@code stream} is {@code null} or closed (i.e. {@link Http2Stream#state()} method returns {@link
     * Http2Stream.State#CLOSED}), calling this method has no effect.
     *
     * @param stream the stream for which window space should be freed. The connection stream object must not be used.
     * If {@code stream} is {@code null} or closed (i.e. {@link Http2Stream#state()} method returns {@link
     * Http2Stream.State#CLOSED}), calling this method has no effect.
     * @param numBytes the number of bytes to be returned to the flow control window.
     * @return true if a {@code WINDOW_UPDATE} was sent, false otherwise.
     * @throws Http2Exception if the number of bytes returned exceeds the {@link #unconsumedBytes(Http2Stream)} for the
     * stream.
     */
    boolean consumeBytes(Http2Stream stream, int numBytes) throws Http2Exception;

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

Params:
  • stream – the stream for which window space should be freed.
Returns:the number of unconsumed bytes for the stream.
/**
     * The number of bytes for the given stream that have been received but not yet consumed by the
     * application.
     *
     * @param stream the stream for which window space should be freed.
     * @return the number of unconsumed bytes for the stream.
     */
    int unconsumedBytes(Http2Stream stream);

    
Get the initial flow control window size for the given stream. This quantity is measured in number of bytes. Note the unavailable window portion can be calculated by Http2FlowController.initialWindowSize() - Http2FlowController.windowSize(Http2Stream). 
/**
     * Get the initial flow control window size for the given stream. This quantity is measured in number of bytes. Note
     * the unavailable window portion can be calculated by {@link #initialWindowSize()} - {@link
     * #windowSize(Http2Stream)}.
     */
    int initialWindowSize(Http2Stream stream);
}