Interface Transformation

  • All Known Implementing Classes:
    PerMessageDeflate

    public interface Transformation
    The internal representation of the transformation that a WebSocket extension performs on a message.
    • Method Summary

      All Methods Instance Methods Abstract Methods 
      Modifier and Type Method Description
      void close()
      Clean-up any resources that were used by the transformation.
      Extension getExtensionResponse()
      Obtain the extension that describes the information to be returned to the client.
      TransformationResult getMoreData​(byte opCode, boolean fin, int rsv, ByteBuffer dest)
      Obtain more input data.
      List<org.apache.tomcat.websocket.MessagePart> sendMessagePart​(List<org.apache.tomcat.websocket.MessagePart> messageParts)
      Takes the provided list of messages, transforms them, passes the transformed list on to the next transformation (if any) and then returns the resulting list of message parts after all of the transformations have been applied.
      void setNext​(Transformation t)
      Sets the next transformation in the pipeline.
      boolean validateRsv​(int rsv, byte opCode)
      Validates the RSV and opcode combination (assumed to have been extracted from a WebSocket Frame) for this extension.
      boolean validateRsvBits​(int i)
      Validate that the RSV bit(s) required by this transformation are not being used by another extension.
    • Method Detail

      • setNext

        void setNext​(Transformation t)
        Sets the next transformation in the pipeline.
        Parameters:
        t - The next transformation
      • validateRsvBits

        boolean validateRsvBits​(int i)
        Validate that the RSV bit(s) required by this transformation are not being used by another extension. The implementation is expected to set any bits it requires before passing the set of in-use bits to the next transformation.
        Parameters:
        i - The RSV bits marked as in use so far as an int in the range zero to seven with RSV1 as the MSB and RSV3 as the LSB
        Returns:
        true if the combination of RSV bits used by the transformations in the pipeline do not conflict otherwise false
      • getExtensionResponse

        Extension getExtensionResponse()
        Obtain the extension that describes the information to be returned to the client.
        Returns:
        The extension information that describes the parameters that have been agreed for this transformation
      • getMoreData

        TransformationResult getMoreData​(byte opCode,
                                         boolean fin,
                                         int rsv,
                                         ByteBuffer dest)
                                  throws IOException
        Obtain more input data.
        Parameters:
        opCode - The opcode for the frame currently being processed
        fin - Is this the final frame in this WebSocket message?
        rsv - The reserved bits for the frame currently being processed
        dest - The buffer in which the data is to be written
        Returns:
        The result of trying to read more data from the transform
        Throws:
        IOException - If an I/O error occurs while reading data from the transform
      • validateRsv

        boolean validateRsv​(int rsv,
                            byte opCode)
        Validates the RSV and opcode combination (assumed to have been extracted from a WebSocket Frame) for this extension. The implementation is expected to unset any RSV bits it has validated before passing the remaining RSV bits to the next transformation in the pipeline.
        Parameters:
        rsv - The RSV bits received as an int in the range zero to seven with RSV1 as the MSB and RSV3 as the LSB
        opCode - The opCode received
        Returns:
        true if the RSV is valid otherwise false
      • sendMessagePart

        List<org.apache.tomcat.websocket.MessagePart> sendMessagePart​(List<org.apache.tomcat.websocket.MessagePart> messageParts)
                                                               throws IOException
        Takes the provided list of messages, transforms them, passes the transformed list on to the next transformation (if any) and then returns the resulting list of message parts after all of the transformations have been applied.
        Parameters:
        messageParts - The list of messages to be transformed
        Returns:
        The list of messages after this any any subsequent transformations have been applied. The size of the returned list may be bigger or smaller than the size of the input list
        Throws:
        IOException - If an error occurs during the transformation of the message parts
      • close

        void close()
        Clean-up any resources that were used by the transformation.