Class CharArrayReader

  • All Implemented Interfaces:
    java.io.Closeable, java.lang.AutoCloseable, java.lang.Readable

    public class CharArrayReader
    extends java.io.Reader
    This class implements a character buffer that can be used as a character-input stream. Modified from the JDK source in that it gets rid of the ensureOpen() method, so we get unexpected behaviour if the reader is closed.

    The second modification is that since this class is used internally by FastPageParser in a single thread, we don't need any locking or synchronization. Using this class instead of the standard CharArrayReader improves FastPageParser performance by 15-20%.

    Author:
    Hani Suleiman
    • Field Summary

      Fields 
      Modifier and Type Field Description
      protected char[] buf
      The character buffer.
      protected int count
      The index of the end of this buffer.
      protected int markedPos
      The position of mark in buffer.
      protected int pos
      The current buffer position.
      • Fields inherited from class java.io.Reader

        lock
    • Constructor Summary

      Constructors 
      Constructor Description
      CharArrayReader​(char[] buf)
      Create an CharArrayReader from the specified array of chars.
      CharArrayReader​(char[] buf, int offset, int length)
      Create an CharArrayReader from the specified array of chars.
    • Method Summary

      All Methods Instance Methods Concrete Methods 
      Modifier and Type Method Description
      void close()
      Close the stream.
      void mark​(int readAheadLimit)
      Mark the present position in the stream.
      boolean markSupported()
      Tell whether this stream supports the mark() operation, which it does.
      int read()
      Read a single character.
      int read​(char[] b, int off, int len)
      Read characters into a portion of an array.
      boolean ready()
      Tell whether this stream is ready to be read.
      void reset()
      Reset the stream to the most recent mark, or to the beginning if it has never been marked.
      long skip​(long n)
      Skip characters.
      • Methods inherited from class java.io.Reader

        nullReader, read, read, transferTo
      • Methods inherited from class java.lang.Object

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

      • buf

        protected char[] buf
        The character buffer.
      • pos

        protected int pos
        The current buffer position.
      • markedPos

        protected int markedPos
        The position of mark in buffer.
      • count

        protected int count
        The index of the end of this buffer. There is not valid data at or beyond this index.
    • Constructor Detail

      • CharArrayReader

        public CharArrayReader​(char[] buf)
        Create an CharArrayReader from the specified array of chars.
        Parameters:
        buf - Input buffer (not copied)
      • CharArrayReader

        public CharArrayReader​(char[] buf,
                               int offset,
                               int length)
        Create an CharArrayReader from the specified array of chars.
        Parameters:
        buf - Input buffer (not copied)
        offset - Offset of the first char to read
        length - Number of chars to read
    • Method Detail

      • read

        public int read()
                 throws java.io.IOException
        Read a single character.
        Overrides:
        read in class java.io.Reader
        Throws:
        java.io.IOException - If an I/O error occurs
      • read

        public int read​(char[] b,
                        int off,
                        int len)
                 throws java.io.IOException
        Read characters into a portion of an array.
        Specified by:
        read in class java.io.Reader
        Parameters:
        b - Destination buffer
        off - Offset at which to start storing characters
        len - Maximum number of characters to read
        Returns:
        The actual number of characters read, or -1 if the end of the stream has been reached
        Throws:
        java.io.IOException - If an I/O error occurs
      • skip

        public long skip​(long n)
                  throws java.io.IOException
        Skip characters.
        Overrides:
        skip in class java.io.Reader
        Parameters:
        n - The number of characters to skip
        Returns:
        The number of characters actually skipped
        Throws:
        java.io.IOException - If an I/O error occurs
      • ready

        public boolean ready()
                      throws java.io.IOException
        Tell whether this stream is ready to be read. Character-array readers are always ready to be read.
        Overrides:
        ready in class java.io.Reader
        Throws:
        java.io.IOException - If an I/O error occurs
      • markSupported

        public boolean markSupported()
        Tell whether this stream supports the mark() operation, which it does.
        Overrides:
        markSupported in class java.io.Reader
      • mark

        public void mark​(int readAheadLimit)
                  throws java.io.IOException
        Mark the present position in the stream. Subsequent calls to reset() will reposition the stream to this point.
        Overrides:
        mark in class java.io.Reader
        Parameters:
        readAheadLimit - Limit on the number of characters that may be read while still preserving the mark. Because the stream's input comes from a character array, there is no actual limit; hence this argument is ignored.
        Throws:
        java.io.IOException - If an I/O error occurs
      • reset

        public void reset()
                   throws java.io.IOException
        Reset the stream to the most recent mark, or to the beginning if it has never been marked.
        Overrides:
        reset in class java.io.Reader
        Throws:
        java.io.IOException - If an I/O error occurs
      • close

        public void close()
        Close the stream.
        Specified by:
        close in interface java.lang.AutoCloseable
        Specified by:
        close in interface java.io.Closeable
        Specified by:
        close in class java.io.Reader