public class

LineNumberReader

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

Class Overview

Wraps an existing Reader and counts the line terminators encountered while reading the data. The line number starts at 0 and is incremented any time '\r', '\n' or "\r\n" is read. The class has an internal buffer for its data. The size of the buffer defaults to 8 KB.

Summary

[Expand]
Inherited Fields
From class java.io.Reader
Public Constructors
LineNumberReader(Reader in)
Constructs a new LineNumberReader on the Reader in.
LineNumberReader(Reader in, int size)
Constructs a new LineNumberReader on the Reader in.
Public Methods
int getLineNumber()
Returns the current line number for this reader.
void mark(int readlimit)
Sets a mark position in this reader.
int read(char[] buffer, int offset, int count)
Reads at most count characters from the source reader and stores them in the character array buffer starting at offset.
int read()
Reads a single character from the source reader and returns it as an integer with the two higher-order bytes set to 0.
String readLine()
Returns the next line of text available from this reader.
void reset()
Resets this reader to the last marked location.
void setLineNumber(int lineNumber)
Sets the line number of this reader to the specified lineNumber.
long skip(long count)
Skips count number of characters in this reader.
[Expand]
Inherited Methods
From class java.io.BufferedReader
From class java.io.Reader
From class java.lang.Object
From interface java.io.Closeable
From interface java.lang.Readable

Public Constructors

public LineNumberReader (Reader in)

Constructs a new LineNumberReader on the Reader in. The internal buffer gets the default size (8 KB).

Parameters
in the Reader that is buffered.

public LineNumberReader (Reader in, int size)

Constructs a new LineNumberReader on the Reader in. The size of the internal buffer is specified by the parameter size.

Parameters
in the Reader that is buffered.
size the size of the buffer to allocate.
Throws
IllegalArgumentException if size <= 0.

Public Methods

public int getLineNumber ()

Returns the current line number for this reader. Numbering starts at 0.

Returns
  • the current line number.

public void mark (int readlimit)

Sets a mark position in this reader. The parameter readlimit indicates how many characters can be read before the mark is invalidated. Sending reset() will reposition this reader back to the marked position, provided that readlimit has not been surpassed. The line number associated with this marked position is also stored so that it can be restored when reset() is called.

Parameters
readlimit the number of characters that can be read from this stream before the mark is invalidated.
Throws
IOException if an error occurs while setting the mark in this reader.
See Also

public int read (char[] buffer, int offset, int count)

Reads at most count characters from the source reader and stores them in the character array buffer starting at offset. Returns the number of characters actually read or -1 if no characters have been read and the end of this reader has been reached.

The line number count is incremented if a line terminator is encountered. Recognized line terminator sequences are '\r', '\n' and "\r\n". Line terminator sequences are always translated into '\n'.

Parameters
buffer the array in which to store the characters read.
offset the initial position in buffer to store the characters read from this reader.
count the maximum number of characters to store in buffer.
Returns
  • the number of characters actually read or -1 if the end of the source reader has been reached while reading.
Throws
IOException if this reader is closed or another IOException occurs.

public int read ()

Reads a single character from the source reader and returns it as an integer with the two higher-order bytes set to 0. Returns -1 if the end of the source reader has been reached.

The line number count is incremented if a line terminator is encountered. Recognized line terminator sequences are '\r', '\n' and "\r\n". Line terminator sequences are always translated into '\n'.

Returns
  • the character read or -1 if the end of the source reader has been reached.
Throws
IOException if the reader is closed or another IOException occurs.

public String readLine ()

Returns the next line of text available from this reader. A line is represented by 0 or more characters followed by '\r', '\n', "\r\n" or the end of the stream. The returned string does not include the newline sequence.

Returns
  • the contents of the line or null if no characters have been read before the end of the stream has been reached.
Throws
IOException if this reader is closed or another IOException occurs.

public void reset ()

Resets this reader to the last marked location. It also resets the line count to what is was when this reader was marked. This implementation resets the source reader.

Throws
IOException if this reader is already closed, no mark has been set or the mark is no longer valid because more than readlimit bytes have been read since setting the mark.
See Also

public void setLineNumber (int lineNumber)

Sets the line number of this reader to the specified lineNumber. Note that this may have side effects on the line number associated with the last marked position.

Parameters
lineNumber the new line number value.
See Also

public long skip (long count)

Skips count number of characters in this reader. Subsequent read()'s will not return these characters unless reset() is used. This implementation skips count number of characters in the source reader and increments the line number count whenever line terminator sequences are skipped.

Parameters
count the number of characters to skip.
Returns
  • the number of characters actually skipped.
Throws
IllegalArgumentException if count < 0.
IOException if this reader is closed or another IOException occurs.
See Also