Class InputStreamWrapper


  • public class InputStreamWrapper
    extends java.lang.Object
    Wrapper for input buffer that supports multiple character encodings. This is needed because the XPP3 pull parser does not support detecting the character encoding for a document based on the content of the document. If used with a common encoding this performs the conversion to characters using an inner reader class; otherwise, this creates the appropriate reader type
    Author:
    Dennis M. Sosnoski
    • Field Summary

      Fields 
      Modifier and Type Field Description
      private byte[] m_buffer
      Cached reference to byte array used by buffer.
      private IInByteBuffer m_byteBuffer
      Input buffer.
      private int m_emptyOffset
      Current offset for generating character from buffer.
      private java.lang.String m_encodingName
      Name of encoding to be used for stream.
      private int m_endOffset
      Offset past end of bytes in buffer.
      private int m_scanOffset
      Scan position offset used for lookahead in buffer.
    • Method Summary

      All Methods Instance Methods Concrete Methods 
      Modifier and Type Method Description
      void close()
      Close document input.
      private boolean fillBuffer()
      Reads data into the buffer.
      IInByteBuffer getBuffer()
      Get input buffer.
      java.lang.String getEncoding()
      Get encoding for input document.
      java.io.Reader getReader()
      Get reader for wrapped input stream.
      private boolean isWhite​(int chr)
      Check if a character is XML whitespace.
      private boolean require​(int min)
      Reads data into the buffer to at least a minimum number of bytes.
      void reset()
      Reset to initial state for reuse.
      private java.lang.String scanQuoted()
      Reads a quote delimited token from the scan position in the buffer.
      private java.lang.String scanToken()
      Reads a space or equals ('=') delimited token from the scan position in the buffer.
      void setBuffer​(IInByteBuffer buff)
      Set the input buffer.
      void setEncoding​(java.lang.String enc)
      Set encoding for stream.
      • Methods inherited from class java.lang.Object

        clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
    • Field Detail

      • m_encodingName

        private java.lang.String m_encodingName
        Name of encoding to be used for stream.
      • m_buffer

        private byte[] m_buffer
        Cached reference to byte array used by buffer.
      • m_endOffset

        private int m_endOffset
        Offset past end of bytes in buffer.
      • m_emptyOffset

        private int m_emptyOffset
        Current offset for generating character from buffer.
      • m_scanOffset

        private int m_scanOffset
        Scan position offset used for lookahead in buffer.
    • Constructor Detail

      • InputStreamWrapper

        public InputStreamWrapper()
    • Method Detail

      • setBuffer

        public void setBuffer​(IInByteBuffer buff)
        Set the input buffer.
        Parameters:
        buff -
      • getBuffer

        public IInByteBuffer getBuffer()
        Get input buffer.
        Returns:
        buffer, null if none set
      • setEncoding

        public void setEncoding​(java.lang.String enc)
                         throws java.io.IOException
        Set encoding for stream. This call is only valid if the encoding has not been set previously, and if the encoding is a recognized type.
        Parameters:
        enc - character encoding used for input from stream (null if to be determined from XML input)
        Throws:
        java.io.IOException - if unknown encoding, or encoding already set
      • fillBuffer

        private boolean fillBuffer()
                            throws java.io.IOException
        Reads data into the buffer. The actual number of bytes read by a call to this method is normally between one and the space available in the buffer array.
        Returns:
        true if data has been read into buffer, false if not
        Throws:
        java.io.IOException - on error reading from stream
      • require

        private boolean require​(int min)
                         throws java.io.IOException
        Reads data into the buffer to at least a minimum number of bytes. Any retained data is first copied down to the start of the buffer array. Next, data is read from the wrapped stream into the available space in the buffer until the end of the input stream is reached or at least the requested number of bytes are present in the buffer.
        Parameters:
        min - number of bytes required
        Returns:
        true if buffer contains at least the required byte count on return, false if not
        Throws:
        java.io.IOException - on error reading from wrapped stream
      • isWhite

        private boolean isWhite​(int chr)
        Check if a character is XML whitespace.
        Parameters:
        chr -
        Returns:
        true if whitespace, false if not
      • scanToken

        private java.lang.String scanToken()
                                    throws java.io.IOException
        Reads a space or equals ('=') delimited token from the scan position in the buffer. This treats bytes in the buffer as equivalent to characters. Besides ending a token on a delimitor, it also ends a token after adding a greater-than ('>') character.
        Returns:
        token read from buffer
        Throws:
        java.io.IOException - on error reading from wrapped stream
      • scanQuoted

        private java.lang.String scanQuoted()
                                     throws java.io.IOException
        Reads a quote delimited token from the scan position in the buffer. This treats bytes in the buffer as equivalent to characters, and skips past any leading whitespace.
        Returns:
        token read from buffer
        Throws:
        java.io.IOException - on error reading from wrapped stream
      • getReader

        public java.io.Reader getReader()
                                 throws java.io.IOException
        Get reader for wrapped input stream. This creates and returns a reader using the appropriate encoding, if necessary reading and examining the first part of the stream (including the XML declaration, if present) to determine the encoding.
        Returns:
        reader
        Throws:
        java.io.IOException - if error reading from document or creating a reader for the encoding found
      • getEncoding

        public java.lang.String getEncoding()
        Get encoding for input document. This call may not return an accurate result until after getReader() is called.
        Returns:
        character encoding for input document
      • close

        public void close()
                   throws java.io.IOException
        Close document input. Completes reading of document input, including closing the input medium.
        Throws:
        java.io.IOException - on error closing document
      • reset

        public void reset()
        Reset to initial state for reuse.