Class LongLineBufferedReader

  • All Implemented Interfaces:
    Closeable, AutoCloseable, Readable

    public class LongLineBufferedReader
    extends Reader
    A variant of BufferedReader with improved performance reading files with long lines. This class is almost identical to BufferedReader, but it retains a single line buffer for accumulating characters in a line, and allows its size to grow. Conversely, BufferedReader assumes each new line will be approximately 80 characters and its performance suffers when that is not the case. Unlike BufferedReader, this class is not thread safe.
    • Constructor Detail

      • LongLineBufferedReader

        public LongLineBufferedReader​(Reader in,
                                      int sz)
        Creates a buffering character-input stream that uses an input buffer of the specified size.
        Parameters:
        in - A Reader
        sz - Input-buffer size
        Throws:
        IllegalArgumentException - If sz is <= 0
      • LongLineBufferedReader

        public LongLineBufferedReader​(Reader in)
        Creates a buffering character-input stream that uses a default-sized input buffer.
        Parameters:
        in - A Reader
    • 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[] cbuf,
                        int off,
                        int len)
                 throws IOException
        Reads characters into a portion of an array.

        This method implements the general contract of the corresponding read method of the Reader class. As an additional convenience, it attempts to read as many characters as possible by repeatedly invoking the read method of the underlying stream. This iterated read continues until one of the following conditions becomes true:

        • The specified number of characters have been read,

        • The read method of the underlying stream returns -1, indicating end-of-file, or

        • The ready method of the underlying stream returns false, indicating that further input requests would block.

        If the first read on the underlying stream returns -1 to indicate end-of-file then this method returns -1. Otherwise this method returns the number of characters actually read.

        Subclasses of this class are encouraged, but not required, to attempt to read as many characters as possible in the same fashion.

        Ordinarily this method takes characters from this stream's character buffer, filling it from the underlying stream as necessary. If, however, the buffer is empty, the mark is not valid, and the requested length is at least as large as the buffer, then this method will read characters directly from the underlying stream into the given array. Thus redundant BufferedReaderTwos will not copy data unnecessarily.

        Specified by:
        read in class Reader
        Parameters:
        cbuf - Destination buffer
        off - Offset at which to start storing characters
        len - Maximum number of characters to read
        Returns:
        The number of characters read, or -1 if the end of the stream has been reached
        Throws:
        IOException - If an I/O error occurs
      • readLine

        public String readLine()
                        throws IOException
        Reads a line of text. A line is considered to be terminated by any one of a line feed ('\n'), a carriage return ('\r'), or a carriage return followed immediately by a linefeed.
        Returns:
        A String containing the contents of the line, not including any line-termination characters, or null if the end of the stream has been reached
        Throws:
        IOException - If an I/O error occurs
      • skip

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

        public boolean ready()
                      throws IOException
        Tells whether this stream is ready to be read. A buffered character stream is ready if the buffer is not empty, or if the underlying character stream is ready.
        Overrides:
        ready in class Reader
        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
      • mark

        public void mark​(int readAheadLimit)
                  throws IOException
        Marks the present position in the stream. Subsequent calls to reset() will attempt to 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. An attempt to reset the stream after reading characters up to this limit or beyond may fail. A limit value larger than the size of the input buffer will cause a new buffer to be allocated whose size is no smaller than limit. Therefore large values should be used with care.
        Throws:
        IllegalArgumentException - If readAheadLimit is < 0
        IOException - If an I/O error occurs
      • reset

        public void reset()
                   throws IOException
        Resets the stream to the most recent mark.
        Overrides:
        reset in class Reader
        Throws:
        IOException - If the stream has never been marked, or if the mark has been invalidated