Repository: netty/netty
File: codec/src/main/java/io/netty/handler/codec/MessageToMessageDecoder.java (Java)

Code before:
        matcher = TypeParameterMatcher.find(this, MessageToMessageDecoder.class, "I");
    }

    /**
     * Create a new instance
     *
     * @param inboundMessageType    The type of messages to match and so decode
     */
    protected MessageToMessageDecoder(Class<? extends I> inboundMessageType) {
        matcher = TypeParameterMatcher.get(inboundMessageType);
    }

    /**
     * Returns {@code true} if the given message should be handled. If {@code false} it will be passed to the next
     * {@link ChannelInboundHandler} in the {@link ChannelPipeline}.
     */
    public boolean acceptInboundMessage(Object msg) throws Exception {
        return matcher.match(msg);
    }

    @Override
    public void channelRead(ChannelHandlerContext ctx, Object msg) throws Exception {
        CodecOutputList out = CodecOutputList.newInstance();
        try {
            if (acceptInboundMessage(msg)) {
                @SuppressWarnings("unchecked")
                I cast = (I) msg;
                try {
                    decode(ctx, cast, out);
                } finally {
                    ReferenceCountUtil.release(cast);
                }
            } else {
                out.add(msg);
            }
        } catch (DecoderException e) {
            throw e;
        } catch (Exception e) {
            throw new DecoderException(e);
        } finally {
            try {
                int size = out.size();
                for (int i = 0; i < size; i++) {
                    ctx.fireChannelRead(out.getUnsafe(i));
                }
            } finally {
                out.recycle();
            }
        }
    }


Review comment (suggestion):
`ensureNotSharable()` is calling `isSharable()` before `this.allowSharable` is set, so it's always going to succeed and therefore is not very useful.


Code after:
     */
    protected MessageToMessageDecoder() {
        matcher = TypeParameterMatcher.find(this, MessageToMessageDecoder.class, "I");
    }

    /**
     * Create a new instance
     *
     * @param inboundMessageType    The type of messages to match and so decode
     */
    protected MessageToMessageDecoder(Class<? extends I> inboundMessageType) {
        matcher = TypeParameterMatcher.get(inboundMessageType);
    }

    /**
     * Returns {@code true} if the given message should be handled. If {@code false} it will be passed to the next
     * {@link ChannelInboundHandler} in the {@link ChannelPipeline}.
     */
    public boolean acceptInboundMessage(Object msg) throws Exception {
        return matcher.match(msg);
    }

    @Override
    public void channelRead(ChannelHandlerContext ctx, Object msg) throws Exception {
        decodeCalled = true;
        CodecOutputList out = CodecOutputList.newInstance();
        try {
            if (acceptInboundMessage(msg)) {
                @SuppressWarnings("unchecked")
                I cast = (I) msg;
                try {
                    decode(ctx, cast, out);
                } finally {
                    ReferenceCountUtil.release(cast);
                }
            } else {
                out.add(msg);
            }
        } catch (DecoderException e) {
            throw e;
        } catch (Exception e) {
            throw new DecoderException(e);
        } finally {
            try {
                int size = out.size();
                messageProduced |= size > 0;
                for (int i = 0; i < size; i++) {
                    ctx.fireChannelRead(out.getUnsafe(i));
                }
            } finally {
                out.recycle();