WebSocketFrameAggregator Class — netty Architecture

Source Code

codec-http/src/main/java/io/netty/handler/codec/http/websocketx/WebSocketFrameAggregator.java lines 31–101

public class WebSocketFrameAggregator
        extends MessageAggregator<WebSocketFrame, WebSocketFrame, ContinuationWebSocketFrame, WebSocketFrame> {

    /**
     * Creates a new instance
     *
     * @param maxContentLength If the size of the aggregated frame exceeds this value,
     *                         a {@link TooLongFrameException} is thrown.
     */
    public WebSocketFrameAggregator(int maxContentLength) {
        super(maxContentLength, WebSocketFrame.class);
    }

    @Override
    protected boolean isStartMessage(WebSocketFrame msg) throws Exception {
        return msg instanceof TextWebSocketFrame || msg instanceof BinaryWebSocketFrame;
    }

    @Override
    protected boolean isContentMessage(WebSocketFrame msg) throws Exception {
        return msg instanceof ContinuationWebSocketFrame;
    }

    @Override
    protected boolean isLastContentMessage(ContinuationWebSocketFrame msg) throws Exception {
        return isContentMessage(msg) && msg.isFinalFragment();
    }

    @Override
    protected boolean isAggregated(WebSocketFrame msg) throws Exception {
        if (msg.isFinalFragment()) {
            return !isContentMessage(msg);
        }

        return !isStartMessage(msg) && !isContentMessage(msg);
    }

    @Override
    protected boolean isContentLengthInvalid(WebSocketFrame start, int maxContentLength) {
        return false;
    }

    @Override
    protected Object newContinueResponse(WebSocketFrame start, int maxContentLength, ChannelPipeline pipeline) {
        return null;
    }

    @Override
    protected boolean closeAfterContinueResponse(Object msg) throws Exception {
        throw new UnsupportedOperationException();
    }

    @Override
    protected boolean ignoreContentAfterContinueResponse(Object msg) throws Exception {
        throw new UnsupportedOperationException();
    }

    @Override
    protected WebSocketFrame beginAggregation(WebSocketFrame start, ByteBuf content) throws Exception {
        if (start instanceof TextWebSocketFrame) {
            return new TextWebSocketFrame(true, start.rsv(), content);
        }

        if (start instanceof BinaryWebSocketFrame) {
            return new BinaryWebSocketFrame(true, start.rsv(), content);
        }

        // Should not reach here.
        throw new Error("Unexpected websocket frame type: " + className(start));
    }
}