LineNumberReader

public class LineNumberReader
extends BufferedReader

java.lang.Object
   ↳ java.io.Reader
     ↳ java.io.BufferedReader
       ↳ java.io.LineNumberReader


A buffered character-input stream that keeps track of line numbers. This class defines methods setLineNumber(int) and getLineNumber() for setting and getting the current line number respectively.

By default, line numbering begins at 0. This number increments at every line terminator as the data is read, and can be changed with a call to setLineNumber(int). Note however, that setLineNumber(int) does not actually change the current position in the stream; it only changes the value that will be returned by getLineNumber().

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.

Summary

Inherited fields

Public constructors

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.

Public methods

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.

Inherited methods

Public constructors

LineNumberReader

added in API level 1
public LineNumberReader (Reader in)

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

Parameters
in Reader: A Reader object to provide the underlying stream

LineNumberReader

added in API level 1
public LineNumberReader (Reader in, 
                int sz)

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

Parameters
in Reader: A Reader object to provide the underlying stream

sz int: An int specifying the size of the buffer

Public methods

getLineNumber

added in API level 1
public int getLineNumber ()

Get the current line number.

Returns
int The current line number

See also:

mark

added in API level 1
public void mark (int readAheadLimit)

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 int: 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

read

added in API level 1
public int read ()

Read a single character. Line terminators are compressed into single newline ('\n') characters. Whenever a line terminator is read the current line number is incremented.

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

Throws
IOException If an I/O error occurs

read

added in API level 1
public int read (char[] cbuf, 
                int off, 
                int len)

Read characters into a portion of an array. Whenever a line terminator is read the current line number is incremented.

Parameters
cbuf char: Destination buffer

off int: Offset at which to start storing characters

len int: Maximum number of characters to read

Returns
int 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

readLine

added in API level 1
public String readLine ()

Read a line of text. Whenever a line terminator is read the current line number is incremented.

Returns
String 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

reset

added in API level 1
public void reset ()

Reset the stream to the most recent mark.

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

setLineNumber

added in API level 1
public void setLineNumber (int lineNumber)

Set the current line number.

Parameters
lineNumber int: An int specifying the line number

See also:

skip

added in API level 1
public long skip (long n)

Skip characters.

Parameters
n long: The number of characters to skip

Returns
long The number of characters actually skipped

Throws
IOException If an I/O error occurs
IllegalArgumentException If n is negative