LineNumberReader - JRE Emulation | JRE Emulation
public class

LineNumberReader

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

Class Overview

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

[Expand]
Inherited Fields
From class java.io.Reader
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
[Expand]
From class java.io.BufferedReader
From class java.io.Reader
From class java.lang.Object
From interface java.lang.Readable
From interface java.io.Closeable
From interface java.lang.AutoCloseable

Public Constructors

public LineNumberReader (Reader in)

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

Parameters
in A Reader object to provide the underlying stream

public LineNumberReader (Reader in, int sz)

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

Parameters
in A Reader object to provide the underlying stream
sz An int specifying the size of the buffer

Public Methods

public int getLineNumber ()

Get the current line number.

Returns
  • The current line number

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 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

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
  • The character read, or -1 if the end of the stream has been reached
Throws
IOException If an I/O error occurs

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 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

public String readLine ()

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

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

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

public void setLineNumber (int lineNumber)

Set the current line number.

Parameters
lineNumber An int specifying the line number
See Also

public long skip (long n)

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
IllegalArgumentException If n is negative