Module java.base
Package java.io

Class CharArrayReader

  • All Implemented Interfaces:
    Closeable, AutoCloseable, Readable
    public class CharArrayReader
extends Reader
    This class implements a character buffer that can be used as a character-input stream.
    Since:
    1.1

    • 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.

    • Constructor Summary

      Constructors 
      Constructor Description
      CharArrayReader​(char[] buf)
      Creates a CharArrayReader from the specified array of chars.
      CharArrayReader​(char[] buf, int offset, int length)
      Creates a CharArrayReader from the specified array of chars.

    • Method Summary

      Modifier and Type Method Description
      void close()
      Closes the stream and releases any system resources associated with it.
      void mark​(int readAheadLimit)
      Marks the present position in the stream.
      boolean markSupported()
      Tells whether this stream supports the mark() operation, which it does.
      int read()
      Reads a single character.
      int read​(char[] b, int off, int len)
      Reads characters into a portion of an array.
      boolean ready()
      Tells whether this stream is ready to be read.
      void reset()
      Resets the stream to the most recent mark, or to the beginning if it has never been marked.
      long skip​(long n)
      Skips characters.

    • 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)
        Creates a CharArrayReader from the specified array of chars.
        Parameters:
        buf - Input buffer (not copied)

      • CharArrayReader

        public CharArrayReader​(char[] buf,
                       int offset,
                       int length)
        Creates a CharArrayReader from the specified array of chars.

        The resulting reader will start reading at the given offset. The total number of char values that can be read from this reader will be either length or buf.length-offset, whichever is smaller.

        Parameters:
        buf - Input buffer (not copied)
        offset - Offset of the first char to read
        length - Number of chars to read
        Throws:
        IllegalArgumentException - If offset is negative or greater than buf.length, or if length is negative, or if the sum of these two values is negative.

    • Method Detail

      • read

        public int read()
         throws IOException
        Reads a single character.
        Overrides:
        read in class Reader
        Returns:
        The character read, as an integer in the range 0 to 65535 (0x00-0xffff), or -1 if the end of the stream has been reached
        Throws:
        IOException - If an I/O error occurs

      • read

        public int read​(char[] b,
                int off,
                int len)
         throws IOException
        Reads characters into a portion of an array.
        Specified by:
        read in class 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:
        IOException - If an I/O error occurs
        IndexOutOfBoundsException - If an I/O error occurs

      • skip

        public long skip​(long n)
          throws IOException
        Skips characters. Returns the number of characters that were skipped.

        The n parameter may be negative, even though the skip method of the Reader superclass throws an exception in this case. If n is negative, then this method does nothing and returns 0.

        Overrides:
        skip in class Reader
        Parameters:
        n - The number of characters to skip
        Returns:
        The number of characters actually skipped
        Throws:
        IOException - If the stream is closed, or an I/O error occurs

      • ready

        public boolean ready()
              throws IOException
        Tells whether this stream is ready to be read. Character-array readers are always ready to be read.
        Overrides:
        ready in class Reader
        Returns:
        True if the next read() is guaranteed not to block for input, false otherwise. Note that returning false does not guarantee that the next read will block.
        Throws:
        IOException - If an I/O error occurs

      • markSupported

        public boolean markSupported()
        Tells whether this stream supports the mark() operation, which it does.
        Overrides:
        markSupported in class Reader
        Returns:
        true if and only if this stream supports the mark operation.

      • mark

        public void mark​(int readAheadLimit)
          throws IOException
        Marks the present position in the stream. Subsequent calls to reset() will reposition the stream to this point.
        Overrides:
        mark in class 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:
        IOException - If an I/O error occurs

      • reset

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

      • close

        public void close()
        Closes the stream and releases any system resources associated with it. Once the stream has been closed, further read(), ready(), mark(), reset(), or skip() invocations will throw an IOException. Closing a previously closed stream has no effect. This method will block while there is another thread blocking on the reader.
        Specified by:
        close in interface AutoCloseable
        Specified by:
        close in interface Closeable
        Specified by:
        close in class Reader