StreamBufferingEncoder Class — netty Architecture

Source Code

codec-http2/src/main/java/io/netty/handler/codec/http2/StreamBufferingEncoder.java lines 57–406

public class StreamBufferingEncoder extends DecoratingHttp2ConnectionEncoder {

    /**
     * Thrown if buffered streams are terminated due to this encoder being closed.
     */
    public static final class Http2ChannelClosedException extends Http2Exception {
        private static final long serialVersionUID = 4768543442094476971L;

        public Http2ChannelClosedException() {
            super(Http2Error.REFUSED_STREAM, "Connection closed");
        }
    }

    private static final class GoAwayDetail {
        private final int lastStreamId;
        private final long errorCode;
        private final byte[] debugData;

        GoAwayDetail(int lastStreamId, long errorCode, byte[] debugData) {
            this.lastStreamId = lastStreamId;
            this.errorCode = errorCode;
            this.debugData = debugData.clone();
        }
    }

    /**
     * Thrown by {@link StreamBufferingEncoder} if buffered streams are terminated due to
     * receipt of a {@code GOAWAY}.
     */
    public static final class Http2GoAwayException extends Http2Exception {
        private static final long serialVersionUID = 1326785622777291198L;
        private final GoAwayDetail goAwayDetail;

        public Http2GoAwayException(int lastStreamId, long errorCode, byte[] debugData) {
            this(new GoAwayDetail(lastStreamId, errorCode, debugData));
        }

        Http2GoAwayException(GoAwayDetail goAwayDetail) {
            super(Http2Error.STREAM_CLOSED);
            this.goAwayDetail = goAwayDetail;
        }

        public int lastStreamId() {
            return goAwayDetail.lastStreamId;
        }

        public long errorCode() {
            return goAwayDetail.errorCode;
        }

        public byte[] debugData() {
            return goAwayDetail.debugData.clone();
        }
    }

    /**
     * Buffer for any streams and corresponding frames that could not be created due to the maximum
     * concurrent stream limit being hit.
     */
    private final TreeMap<Integer, PendingStream> pendingStreams = new TreeMap<Integer, PendingStream>();
    private int maxConcurrentStreams;
    private boolean closed;
    private GoAwayDetail goAwayDetail;

    public StreamBufferingEncoder(Http2ConnectionEncoder delegate) {
        this(delegate, SMALLEST_MAX_CONCURRENT_STREAMS);
    }

    public StreamBufferingEncoder(Http2ConnectionEncoder delegate, int initialMaxConcurrentStreams) {
        super(delegate);
        maxConcurrentStreams = initialMaxConcurrentStreams;
        connection().addListener(new Http2ConnectionAdapter() {

            @Override
            public void onGoAwayReceived(int lastStreamId, long errorCode, ByteBuf debugData) {
                goAwayDetail = new GoAwayDetail(
                    // Using getBytes(..., false) is safe here as GoAwayDetail(...) will clone the byte[].
                    lastStreamId, errorCode,
                    ByteBufUtil.getBytes(debugData, debugData.readerIndex(), debugData.readableBytes(), false));
                cancelGoAwayStreams(goAwayDetail);
            }