Http2FlowController Type — netty Architecture

Source Code

codec-http2/src/main/java/io/netty/handler/codec/http2/Http2FlowController.java lines 22–79

public interface Http2FlowController {
    /**
     * Set the {@link ChannelHandlerContext} for which to apply flow control on.
     * <p>
     * This <strong>must</strong> be called to properly initialize the {@link Http2FlowController}.
     * Not calling this is considered a programming error.
     * @param ctx The {@link ChannelHandlerContext} for which to apply flow control on.
     * @throws Http2Exception if any protocol-related error occurred.
     */
    void channelHandlerContext(ChannelHandlerContext ctx) throws Http2Exception;

    /**
     * Sets the connection-wide initial flow control window and updates all stream windows (but not the connection
     * stream window) by the delta.
     * <p>
     * Represents the value for
     * <a href="https://tools.ietf.org/html/rfc7540#section-6.5.2">SETTINGS_INITIAL_WINDOW_SIZE</a>. This method should
     * only be called by Netty (not users) as a result of a receiving a {@code SETTINGS} frame.
     *
     * @param newWindowSize the new initial window size.
     * @throws Http2Exception thrown if any protocol-related error occurred.
     */
    void initialWindowSize(int newWindowSize) throws Http2Exception;

    /**
     * Gets the connection-wide initial flow control window size that is used as the basis for new stream flow
     * control windows.
     * <p>
     * Represents the value for
     * <a href="https://tools.ietf.org/html/rfc7540#section-6.5.2">SETTINGS_INITIAL_WINDOW_SIZE</a>. The initial value
     * returned by this method must be {@link Http2CodecUtil#DEFAULT_WINDOW_SIZE}.
     */
    int initialWindowSize();

    /**
     * Get the portion of the flow control window for the given stream that is currently available for sending/receiving
     * frames which are subject to flow control. This quantity is measured in number of bytes.
     */
    int windowSize(Http2Stream stream);

    /**
     * Increments the size of the stream's flow control window by the given delta.
     * <p>
     * In the case of a {@link Http2RemoteFlowController} this is called upon receipt of a
     * {@code WINDOW_UPDATE} frame from the remote endpoint to mirror the changes to the window
     * size.
     * <p>
     * For a {@link 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
     * {@code WINDOW_UPDATE} is actually sent.
     *
     * @param stream The subject stream. Use {@link Http2Connection#connectionStream()} for
     *            requesting the size of the connection window.
     * @param delta the change in size of the flow control window.
     * @throws Http2Exception thrown if a protocol-related error occurred.
     */
    void incrementWindowSize(Http2Stream stream, int delta) throws Http2Exception;
}