Class HTMLScanner.PlaybackInputStream

  • All Implemented Interfaces:
    java.io.Closeable, java.lang.AutoCloseable
    Enclosing class:
    HTMLScanner

    public static class HTMLScanner.PlaybackInputStream
    extends java.io.FilterInputStream
    A playback input stream. This class has the ability to save the bytes read from the underlying input stream and play the bytes back later. This class is used by the HTML scanner to switch encodings when a <meta> tag is detected that specifies a different encoding.

    If the encoding is changed, then the scanner calls the playback method and re-scans the beginning of the HTML document again. This should not be too much of a performance problem because the <meta> tag appears at the beginning of the document.

    If the <body> tag is reached without playing back the bytes, then the buffer can be cleared by calling the clear method. This stops the buffering of bytes and allows the memory used by the buffer to be reclaimed.

    Note: If the buffer is never played back or cleared, this input stream will continue to buffer the entire stream. Therefore, it is very important to use this stream correctly.

    Author:
    Andy Clark
    • Field Summary

      Fields 
      Modifier and Type Field Description
      protected byte[] fByteBuffer
      Byte buffer.
      protected int fByteLength
      Length of bytes read into byte buffer.
      protected int fByteOffset
      Offset into byte buffer during playback.
      protected boolean fCleared
      Buffer cleared.
      protected boolean fDetected
      Encoding detected.
      protected boolean fPlayback
      Playback mode.
      int fPushbackLength
      Pushback length.
      int fPushbackOffset
      Pushback offset.
      • Fields inherited from class java.io.FilterInputStream

        in
    • Constructor Summary

      Constructors 
      Constructor Description
      PlaybackInputStream​(java.io.InputStream in)
      Constructor.
    • Method Summary

      All Methods Instance Methods Concrete Methods 
      Modifier and Type Method Description
      void clear()
      Clears the buffer.
      void detectEncoding​(java.lang.String[] encodings)
      Detect encoding.
      void playback()
      Playback buffer contents.
      int read()
      Read a byte.
      int read​(byte[] array)
      Read an array of bytes.
      int read​(byte[] array, int offset, int length)
      Read an array of bytes.
      • Methods inherited from class java.io.FilterInputStream

        available, close, mark, markSupported, reset, skip
      • Methods inherited from class java.io.InputStream

        nullInputStream, readAllBytes, readNBytes, readNBytes, transferTo
      • Methods inherited from class java.lang.Object

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

      • fPlayback

        protected boolean fPlayback
        Playback mode.
      • fCleared

        protected boolean fCleared
        Buffer cleared.
      • fDetected

        protected boolean fDetected
        Encoding detected.
      • fByteBuffer

        protected byte[] fByteBuffer
        Byte buffer.
      • fByteOffset

        protected int fByteOffset
        Offset into byte buffer during playback.
      • fByteLength

        protected int fByteLength
        Length of bytes read into byte buffer.
      • fPushbackOffset

        public int fPushbackOffset
        Pushback offset.
      • fPushbackLength

        public int fPushbackLength
        Pushback length.
    • Constructor Detail

      • PlaybackInputStream

        public PlaybackInputStream​(java.io.InputStream in)
        Constructor.
    • Method Detail

      • detectEncoding

        public void detectEncoding​(java.lang.String[] encodings)
                            throws java.io.IOException
        Detect encoding.
        Throws:
        java.io.IOException
      • playback

        public void playback()
        Playback buffer contents.
      • clear

        public void clear()
        Clears the buffer.

        Note: The buffer cannot be cleared during playback. Therefore, calling this method during playback will not do anything. However, the buffer will be cleared automatically at the end of playback.

      • read

        public int read()
                 throws java.io.IOException
        Read a byte.
        Overrides:
        read in class java.io.FilterInputStream
        Throws:
        java.io.IOException
      • read

        public int read​(byte[] array)
                 throws java.io.IOException
        Read an array of bytes.
        Overrides:
        read in class java.io.FilterInputStream
        Throws:
        java.io.IOException
      • read

        public int read​(byte[] array,
                        int offset,
                        int length)
                 throws java.io.IOException
        Read an array of bytes.
        Overrides:
        read in class java.io.FilterInputStream
        Throws:
        java.io.IOException