Class JsonObjectDecoder

  • All Implemented Interfaces:
    ChannelHandler, ChannelInboundHandler

    public class JsonObjectDecoder
    extends ByteToMessageDecoder
    Splits a byte stream of JSON objects and arrays into individual objects/arrays and passes them up the ChannelPipeline.

    The byte stream is expected to be in UTF-8 character encoding or ASCII. The current implementation uses direct byte to char cast and then compares that char to a few low range ASCII characters like {@code '{'}, {@code '['} or {@code '"'}. UTF-8 is not using low range [0..0x7F] byte values for multibyte codepoint representations therefore fully supported by this implementation.

    This class does not do any real parsing or validation. A sequence of bytes is considered a JSON object/array if it contains a matching number of opening and closing braces/brackets. It's up to a subsequent {@link ChannelHandler} to parse the JSON text into a more usable form i.e. a POJO.

    • Constructor Detail

      • JsonObjectDecoder

        public JsonObjectDecoder()
      • JsonObjectDecoder

        public JsonObjectDecoder​(int maxObjectLength)
      • JsonObjectDecoder

        public JsonObjectDecoder​(boolean streamArrayElements)
      • JsonObjectDecoder

        public JsonObjectDecoder​(int maxObjectLength,
                                 boolean streamArrayElements)
        Parameters:
        maxObjectLength - maximum number of bytes a JSON object/array may use (including braces and all). Objects exceeding this length are dropped and an TooLongFrameException is thrown.
        streamArrayElements - if set to true and the "top level" JSON object is an array, each of its entries is passed through the pipeline individually and immediately after it was fully received, allowing for arrays with "infinitely" many elements.
    • Method Detail

      • extractObject

        protected ByteBuf extractObject​(ChannelHandlerContext ctx,
                                        ByteBuf buffer,
                                        int index,
                                        int length)
        Override this method if you want to filter the json objects/arrays that get passed through the pipeline.