Class LineBasedFrameDecoder

All Implemented Interfaces:
ChannelHandler, ChannelUpstreamHandler, LifeCycleAwareChannelHandler

public class LineBasedFrameDecoder extends FrameDecoder
A decoder that splits the received ChannelBuffers on line endings.

Both "\n" and "\r\n" are handled. For a more general delimiter-based decoder, see DelimiterBasedFrameDecoder.

  • Field Details

    • maxLength

      private final int maxLength
      Maximum length of a frame we're willing to decode.
    • failFast

      private final boolean failFast
      Whether or not to throw an exception as soon as we exceed maxLength.
    • stripDelimiter

      private final boolean stripDelimiter
    • discarding

      private boolean discarding
      True if we're discarding input because we're already over maxLength.
    • discardedBytes

      private int discardedBytes
  • Constructor Details

    • LineBasedFrameDecoder

      public LineBasedFrameDecoder(int maxLength)
      Creates a new decoder.
      Parameters:
      maxLength - the maximum length of the decoded frame. A TooLongFrameException is thrown if the length of the frame exceeds this value.
    • LineBasedFrameDecoder

      public LineBasedFrameDecoder(int maxLength, boolean stripDelimiter, boolean failFast)
      Creates a new decoder.
      Parameters:
      maxLength - the maximum length of the decoded frame. A TooLongFrameException is thrown if the length of the frame exceeds this value.
      stripDelimiter - whether the decoded frame should strip out the delimiter or not
      failFast - If true, a TooLongFrameException is thrown as soon as the decoder notices the length of the frame will exceed maxFrameLength regardless of whether the entire frame has been read. If false, a TooLongFrameException is thrown after the entire frame that exceeds maxFrameLength has been read.
  • Method Details

    • decode

      protected Object decode(ChannelHandlerContext ctx, Channel channel, ChannelBuffer buffer) throws Exception
      Description copied from class: FrameDecoder
      Decodes the received packets so far into a frame. If an sub-class wants to extract a frame out of the buffer it should use the FrameDecoder.extractFrame(ChannelBuffer, int, int) method, to make optimizations easier later.
      Specified by:
      decode in class FrameDecoder
      Parameters:
      ctx - the context of this handler
      channel - the current channel
      buffer - the cumulative buffer of received packets so far. Note that the buffer might be empty, which means you should not make an assumption that the buffer contains at least one byte in your decoder implementation.
      Returns:
      the decoded frame if a full frame was received and decoded. null if there's not enough data in the buffer to decode a frame.
      Throws:
      Exception
    • fail

      private void fail(ChannelHandlerContext ctx, int length)
    • fail

      private void fail(ChannelHandlerContext ctx, String length)
    • findEndOfLine

      private static int findEndOfLine(ChannelBuffer buffer)
      Returns the index in the buffer of the end of line found. Returns -1 if no end of line was found in the buffer.