StompSubframeEncoder Class — netty Architecture

Source Code

codec-stomp/src/main/java/io/netty/handler/codec/stomp/StompSubframeEncoder.java lines 53–251

public class StompSubframeEncoder extends MessageToMessageEncoder<StompSubframe> {

    private static final int ESCAPE_HEADER_KEY_CACHE_LIMIT = 32;
    private static final float DEFAULT_LOAD_FACTOR = 0.75f;
    private static final FastThreadLocal<LinkedHashMap<CharSequence, CharSequence>> ESCAPE_HEADER_KEY_CACHE =
            new FastThreadLocal<LinkedHashMap<CharSequence, CharSequence>>() {
                @Override
                protected LinkedHashMap<CharSequence, CharSequence> initialValue() throws Exception {
                    LinkedHashMap<CharSequence, CharSequence> cache = new LinkedHashMap<CharSequence, CharSequence>(
                            ESCAPE_HEADER_KEY_CACHE_LIMIT, DEFAULT_LOAD_FACTOR, true) {

                        @Override
                        protected boolean removeEldestEntry(Entry eldest) {
                            return size() > ESCAPE_HEADER_KEY_CACHE_LIMIT;
                        }
                    };

                    cache.put(ACCEPT_VERSION, ACCEPT_VERSION);
                    cache.put(HOST, HOST);
                    cache.put(LOGIN, LOGIN);
                    cache.put(PASSCODE, PASSCODE);
                    cache.put(HEART_BEAT, HEART_BEAT);
                    cache.put(VERSION, VERSION);
                    cache.put(SESSION, SESSION);
                    cache.put(SERVER, SERVER);
                    cache.put(DESTINATION, DESTINATION);
                    cache.put(ID, ID);
                    cache.put(ACK, ACK);
                    cache.put(TRANSACTION, TRANSACTION);
                    cache.put(RECEIPT, RECEIPT);
                    cache.put(MESSAGE_ID, MESSAGE_ID);
                    cache.put(SUBSCRIPTION, SUBSCRIPTION);
                    cache.put(RECEIPT_ID, RECEIPT_ID);
                    cache.put(MESSAGE, MESSAGE);
                    cache.put(CONTENT_LENGTH, CONTENT_LENGTH);
                    cache.put(CONTENT_TYPE, CONTENT_TYPE);

                    return cache;
                }
            };

    public StompSubframeEncoder() {
        super(StompSubframe.class);
    }

    @Override
    protected void encode(ChannelHandlerContext ctx, StompSubframe msg, List<Object> out) throws Exception {
        if (msg instanceof StompFrame) {
            StompFrame stompFrame = (StompFrame) msg;
            ByteBuf buf = encodeFullFrame(stompFrame, ctx);

            out.add(convertFullFrame(stompFrame, buf));
        } else if (msg instanceof StompHeadersSubframe) {
            StompHeadersSubframe stompHeadersSubframe = (StompHeadersSubframe) msg;
            ByteBuf buf = ctx.alloc().buffer(headersSubFrameSize(stompHeadersSubframe));
            encodeHeaders(stompHeadersSubframe, buf);

            out.add(convertHeadersSubFrame(stompHeadersSubframe, buf));
        } else if (msg instanceof StompContentSubframe) {
            StompContentSubframe stompContentSubframe = (StompContentSubframe) msg;
            ByteBuf buf = encodeContent(stompContentSubframe, ctx);

            out.add(convertContentSubFrame(stompContentSubframe, buf));
        }
    }

    /**
     * An extension method to convert a STOMP encoded buffer to a different message type
     * based on an original {@link StompFrame} full frame.
     *
     * <p>By default an encoded buffer is returned as is.
     */
    protected Object convertFullFrame(StompFrame original, ByteBuf encoded) {
        return encoded;
    }

    /**
     * An extension method to convert a STOMP encoded buffer to a different message type
     * based on an original {@link StompHeadersSubframe} headers sub frame.
     *
     * <p>By default an encoded buffer is returned as is.