OpenJDK 27 · java.io.LineNumberReader · APIdia, the JavaDoc alternative

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 at the end of the stream if the last character in the stream is not a line terminator. This number 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, or any of the previous terminators followed by end of stream, or end of stream not preceded by another terminator.

Field Summary

Modifier and Type	Field and Description
private static final int	CHAR
private static final int	EOF
private static final int	EOL
private int	lineNumber The current line number
private int	markedLineNumber The line number of the mark, if any
private boolean	markedSkipLF Hides java.io.BufferedReader.markedSkipLF. The skipLF flag when the mark was set
private static final int	maxSkipBufferSize Hides java.io.Reader.maxSkipBufferSize. Maximum skip-buffer size
private static final int	NONE Previous character types
private int	prevChar The previous character type
private char[]	skipBuffer Hides java.io.Reader.skipBuffer. Skip buffer, null until allocated
private boolean	skipLF Hides java.io.BufferedReader.skipLF. If the next character is a line feed, skip it

Constructor Summary

Access	Constructor and Description
public	LineNumberReader(Reader A Reader object to provide the underlying stream in) Create a new line-numbering reader, using the default input-buffer size.
public	LineNumberReader(Reader A Reader object to provide the underlying stream in, int An int specifying the size of the buffer sz) Create a new line-numbering reader, reading characters into a buffer of the given size.

Method Summary

Modifier and Type	Method and Description
public int	Returns: The current line number getLineNumber() Get the current line number.
public void	mark(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. readAheadLimit) Overrides java.io.BufferedReader.mark. Mark the present position in the stream.
public int	Returns: The character read, or -1 if the end of the stream has been reached read() Overrides java.io.BufferedReader.read. Read a single character.
public int	read(char[] cbuf, int off, int len) Overrides java.io.BufferedReader.read. Reads characters into a portion of an array.
public String	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 readLine() Overrides java.io.BufferedReader.readLine. Read a line of text.
public void	reset() Overrides java.io.BufferedReader.reset. Reset the stream to the most recent mark.
public void	setLineNumber(int An int specifying the line number lineNumber) Set the current line number.
public long	skip(long n) Overrides java.io.BufferedReader.skip. Skips characters.

Inherited from java.io.BufferedReader:: close lines markSupported readLine ready

Field Detail

CHAR	back to summary
private static final int CHAR

EOF	back to summary
private static final int EOF

EOL	back to summary
private static final int EOL

lineNumber	back to summary
private int lineNumber The current line number

markedLineNumber	back to summary
private int markedLineNumber The line number of the mark, if any

markedSkipLF	back to summary
private boolean markedSkipLF Hides java.io.BufferedReader.markedSkipLF. The skipLF flag when the mark was set

markedSkipLF

back to summary

private boolean markedSkipLF

Hides java.io.BufferedReader.markedSkipLF.

The skipLF flag when the mark was set

maxSkipBufferSize	back to summary
private static final int maxSkipBufferSize Hides java.io.Reader.maxSkipBufferSize. Maximum skip-buffer size

maxSkipBufferSize

back to summary

private static final int maxSkipBufferSize

Hides java.io.Reader.maxSkipBufferSize.

Maximum skip-buffer size

NONE	back to summary
private static final int NONE Previous character types

prevChar	back to summary
private int prevChar The previous character type

skipBuffer	back to summary
private char[] skipBuffer Hides java.io.Reader.skipBuffer. Skip buffer, null until allocated

skipBuffer

back to summary

private char[] skipBuffer

Hides java.io.Reader.skipBuffer.

Skip buffer, null until allocated

skipLF	back to summary
private boolean skipLF Hides java.io.BufferedReader.skipLF. If the next character is a line feed, skip it

skipLF

back to summary

private boolean skipLF

Hides java.io.BufferedReader.skipLF.

If the next character is a line feed, skip it

Constructor Detail

LineNumberReader	back to summary
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

back to summary

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	back to summary
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

LineNumberReader

back to summary

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

Method Detail

getLineNumber back to summary

getLineNumber	back to summary
public int getLineNumber() Get the current line number. Returns:int The current line number See Also `setLineNumber`

public int getLineNumber()

Get the current line number.

Returns:int: The current line number
See Also: setLineNumber

mark	back to summary
public void mark(int readAheadLimit) throws IOException Overrides java.io.BufferedReader.mark. 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. Exceptions IOException: If an I/O error occurs

mark

back to summary

public void mark(int readAheadLimit) throws IOException

Overrides java.io.BufferedReader.mark.

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.

Exceptions

IOException:: If an I/O error occurs

read	back to summary
public int read() throws IOException Overrides java.io.BufferedReader.read. Read a single character. Line terminators are compressed into single newline ('\n') characters. The current line number is incremented whenever a line terminator is read, or when the end of the stream is reached and the last character in the stream is not a line terminator. Returns:int The character read, or -1 if the end of the stream has been reached Annotations @SuppressWarnings:fallthrough Exceptions IOException: If an I/O error occurs

read

back to summary

public int read() throws IOException

Overrides java.io.BufferedReader.read.

Read a single character. Line terminators are compressed into single newline ('\n') characters. The current line number is incremented whenever a line terminator is read, or when the end of the stream is reached and the last character in the stream is not a line terminator.

Returns:int

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

Annotations

@SuppressWarnings:fallthrough

Exceptions

IOException:: If an I/O error occurs

read back to summary

read	back to summary
public int read(char[] cbuf, int off, int len) throws IOException Overrides java.io.BufferedReader.read. Reads characters into a portion of an array. This method will block until some input is available, an I/O error occurs, or the end of the stream is reached. If `len` is zero, then no characters are read and `0` is returned; otherwise, there is an attempt to read at least one character. If no character is available because the stream is at its end, the value `-1` is returned; otherwise, at least one character is read and stored into `cbuf`. Line terminators are compressed into single newline ('\n') characters. The current line number is incremented whenever a line terminator is read, or when the end of the stream is reached and the last character in the stream is not a line terminator. Annotations @SuppressWarnings:fallthrough Exceptions IOException: If an I/O error occurs IndexOutOfBoundsException: If `off` is negative, or `len` is negative, or `len` is greater than `cbuf.length - off`

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

Overrides java.io.BufferedReader.read.

Reads characters into a portion of an array. This method will block until some input is available, an I/O error occurs, or the end of the stream is reached.

If len is zero, then no characters are read and 0 is returned; otherwise, there is an attempt to read at least one character. If no character is available because the stream is at its end, the value -1 is returned; otherwise, at least one character is read and stored into cbuf.

Line terminators are compressed into single newline ('\n') characters. The current line number is incremented whenever a line terminator is read, or when the end of the stream is reached and the last character in the stream is not a line terminator.

Annotations

@SuppressWarnings:fallthrough

Exceptions

IOException:: If an I/O error occurs
IndexOutOfBoundsException:: If off is negative, or len is negative, or len is greater than cbuf.length - off

readLine back to summary

readLine	back to summary
public String readLine() throws IOException Overrides java.io.BufferedReader.readLine. Read a line of text. Line terminators are compressed into single newline ('\n') characters. The current line number is incremented whenever a line terminator is read, or when the end of the stream is reached and the last character in the stream is not a line terminator. 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 Exceptions IOException: If an I/O error occurs

public String readLine() throws IOException

Overrides java.io.BufferedReader.readLine.

Read a line of text. Line terminators are compressed into single newline ('\n') characters. The current line number is incremented whenever a line terminator is read, or when the end of the stream is reached and the last character in the stream is not a line terminator.

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

Exceptions

IOException:: If an I/O error occurs

reset	back to summary
public void reset() throws IOException Overrides java.io.BufferedReader.reset. Reset the stream to the most recent mark. Exceptions IOException: If the stream has not been marked, or if the mark has been invalidated

reset

back to summary

public void reset() throws IOException

Overrides java.io.BufferedReader.reset.

Reset the stream to the most recent mark.

Exceptions

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

setLineNumber back to summary

setLineNumber	back to summary
public void setLineNumber(int lineNumber) Set the current line number. Parameters lineNumber:int An int specifying the line number See Also `getLineNumber`

public void setLineNumber(int lineNumber)

Set the current line number.

Parameters

lineNumber:int: An int specifying the line number

See Also

getLineNumber

skip	back to summary
public long skip(long n) throws IOException Overrides java.io.BufferedReader.skip. Doc from java.io.BufferedReader.skip. Skips characters. This method will block until some characters are available, an I/O error occurs, or the end of the stream is reached. If the stream is already at its end before this method is invoked, then no characters are skipped and zero is returned. Exceptions IOException: Doc from java.io.Reader.skip. If an I/O error occurs

skip

back to summary

public long skip(long n) throws IOException

Overrides java.io.BufferedReader.skip.

Doc from java.io.BufferedReader.skip.

Skips characters. This method will block until some characters are available, an I/O error occurs, or the end of the stream is reached. If the stream is already at its end before this method is invoked, then no characters are skipped and zero is returned.

Exceptions

IOException:

Doc from java.io.Reader.skip.

If an I/O error occurs

public Class LineNumberReader

Field Summary

Constructor Summary

Method Summary

Field Detail

Constructor Detail

Method Detail