java.io
Class LineNumberReader

java.lang.Object
  |
  +--java.io.Reader
        |
        +--java.io.BufferedReader
              |
              +--java.io.LineNumberReader

public class LineNumberReader

extends BufferedReader

A buffered character-input stream that keeps track of line numbers. 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.

Since:

JDK1.1

Field Summary

private int	lineNumber The current line number
private int	markedLineNumber The line number of the mark, if any
private boolean	markedSkipLF The skipLF flag when the mark was set
private static int	maxSkipBufferSize Maximum skip-buffer size
private char[]	skipBuffer Skip buffer, null until allocated
private boolean	skipLF If the next character is a line feed, skip it

Fields inherited from class java.io.BufferedReader

cb, defaultCharBufferSize, defaultExpectedLineLength, in, INVALIDATED, markedChar, nChars, nextChar, readAheadLimit, UNMARKED

Fields inherited from class java.io.Reader

lock, maxSkipBufferSize, skipBuffer

Constructor Summary

LineNumberReader(Reader in)
Create a new line-numbering reader, using the default input-buffer size.

LineNumberReader(Reader in, int sz)
Create a new line-numbering reader, reading characters into a buffer of the given size.

Method Summary

int	getLineNumber() Get the current line number.
void	mark(int readAheadLimit) Mark the present position in the stream.
int	read() Read a single character.
int	read(char[] cbuf, int off, int len) Read characters into a portion of an array.
String	readLine() Read a line of text.
void	reset() Reset the stream to the most recent mark.
void	setLineNumber(int lineNumber) Set the current line number.
long	skip(long n) Skip characters.

Methods inherited from class java.io.BufferedReader

close, ensureOpen, fill, markSupported, read1, readLine, ready

Methods inherited from class java.io.Reader

read

Methods inherited from class java.lang.Object

, clone, equals, finalize, getClass, hashCode, notify, notifyAll, registerNatives, toString, wait, wait, wait

Field Detail

lineNumber

private int lineNumber

The current line number

markedLineNumber

private int markedLineNumber

The line number of the mark, if any

skipLF

private boolean skipLF

If the next character is a line feed, skip it

markedSkipLF

private boolean markedSkipLF

The skipLF flag when the mark was set

maxSkipBufferSize

private static final int maxSkipBufferSize

Maximum skip-buffer size

skipBuffer

private char[] skipBuffer

Skip buffer, null until allocated

Constructor Detail

LineNumberReader

public LineNumberReader(Reader in)

Create a new line-numbering reader, using the default input-buffer size.

LineNumberReader

public LineNumberReader(Reader in,
                        int sz)

Create a new line-numbering reader, reading characters into a buffer of the given size.

Method Detail

setLineNumber

public void setLineNumber(int lineNumber)

Set the current line number.

getLineNumber

public int getLineNumber()

Get the current line number.

read

public int read()
         throws IOException

Read a single character. Line terminators are compressed into single newline ('\n') characters.

Returns:

The character read, or -1 if the end of the stream has been reached

Throws:

IOException - If an I/O error occurs

Overrides:

read in class BufferedReader

read

public int read(char[] cbuf,
                int off,
                int len)
         throws IOException

Read characters into a portion of an array.

Parameters:

cbuf - Destination buffer

off - Offset at which to start storing characters

len - Maximum number of characters to read

Returns:

The number of bytes read, or -1 if the end of the stream has already been reached

Throws:

IOException - If an I/O error occurs

Overrides:

read in class BufferedReader

readLine

public String readLine()
                throws IOException

Read 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

Overrides:

readLine in class BufferedReader

skip

public long skip(long n)
          throws IOException

Skip characters.

Parameters:

n - The number of characters to skip

Returns:

The number of characters actually skipped

Throws:

IOException - If an I/O error occurs

Overrides:

skip in class BufferedReader

mark

public void mark(int readAheadLimit)
          throws IOException

Mark the present position in the stream. Subsequent calls to reset() will attempt to reposition the stream to this point, and will also reset the line number appropriately.

Parameters:

readAheadLimit - Limit on the number of characters that may be read while still preserving the mark. After reading this many characters, attempting to reset the stream may fail.

Throws:

IOException - If an I/O error occurs

Overrides:

mark in class BufferedReader

reset

public void reset()
           throws IOException

Reset the stream to the most recent mark.

Throws:

IOException - If the stream has not been marked, or if the mark has been invalidated

Overrides:

reset in class BufferedReader