Http2RemoteFlowController Type — netty Architecture

Source Code

codec-http2/src/main/java/io/netty/handler/codec/http2/Http2RemoteFlowController.java lines 23–168

public interface Http2RemoteFlowController extends Http2FlowController {
    /**
     * Get the {@link ChannelHandlerContext} for which to apply flow control on.
     * <p>
     * This is intended for us by {@link FlowControlled} implementations only. Use with caution.
     * @return The {@link ChannelHandlerContext} for which to apply flow control on.
     */
    ChannelHandlerContext channelHandlerContext();

    /**
     * Queues a payload for transmission to the remote endpoint. There is no guarantee as to when the data
     * will be written or how it will be assigned to frames.
     * before sending.
     * <p>
     * Writes do not actually occur until {@link #writePendingBytes()} is called.
     *
     * @param stream the subject stream. Must not be the connection stream object.
     * @param payload payload to write subject to flow-control accounting and ordering rules.
     */
    void addFlowControlled(Http2Stream stream, FlowControlled payload);

    /**
     * Determine if {@code stream} has any {@link FlowControlled} frames currently queued.
     * @param stream the stream to check if it has flow controlled frames.
     * @return {@code true} if {@code stream} has any {@link FlowControlled} frames currently queued.
     */
    boolean hasFlowControlled(Http2Stream stream);

    /**
     * Write all data pending in the flow controller up to the flow-control limits.
     *
     * @throws Http2Exception throws if a protocol-related error occurred.
     */
    void writePendingBytes() throws Http2Exception;

    /**
     * Set the active listener on the flow-controller.
     *
     * @param listener to notify when the a write occurs, can be {@code null}.
     */
    void listener(Listener listener);

    /**
     * Determine if the {@code stream} has bytes remaining for use in the flow control window.
     * <p>
     * Note that this method respects channel writability. The channel must be writable for this method to
     * return {@code true}.
     *
     * @param stream The stream to test.
     * @return {@code true} if the {@code stream} has bytes remaining for use in the flow control window and the
     * channel is writable, {@code false} otherwise.
     */
    boolean isWritable(Http2Stream stream);

    /**
     * Notification that the writability of {@link #channelHandlerContext()} has changed.
     * @throws Http2Exception If any writes occur as a result of this call and encounter errors.
     */
    void channelWritabilityChanged() throws Http2Exception;

    /**
     * Explicitly update the dependency tree. This method is called independently of stream state changes.
     * @param childStreamId The stream identifier associated with the child stream.
     * @param parentStreamId The stream identifier associated with the parent stream. May be {@code 0},
     *                       to make {@code childStreamId} and immediate child of the connection.
     * @param weight The weight which is used relative to other child streams for {@code parentStreamId}. This value
     *               must be between 1 and 256 (inclusive).
     * @param exclusive If {@code childStreamId} should be the exclusive dependency of {@code parentStreamId}.
     */
    void updateDependencyTree(int childStreamId, int parentStreamId, short weight, boolean exclusive);

    /**
     * Implementations of this interface are used to progressively write chunks of the underlying
     * payload to the stream. A payload is considered to be fully written if {@link #write} has
     * been called at least once and it's {@link #size} is now zero.
     */
    interface FlowControlled {
        /**
         * The size of the payload in terms of bytes applied to the flow-control window.
         * Some payloads like {@code HEADER} frames have no cost against flow control and would
         * return 0 for this value even though they produce a non-zero number of bytes on