Closeable
, AutoCloseable
, Readable
public class LineNumberReader extends BufferedReader
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.
Constructor | Description |
---|---|
LineNumberReader |
Create a new line-numbering reader, using the default input-buffer size. |
LineNumberReader |
Create a new line-numbering reader, reading characters into a buffer of the given size. |
Modifier and Type | Method | Description |
---|---|---|
int |
getLineNumber() |
Get the current line number. |
void |
mark |
Mark the present position in the stream. |
int |
read() |
Read a single character. |
int |
read |
Reads 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 |
Set the current line number. |
close, lines, markSupported, ready
nullReader, read, read, skip, transferTo
public LineNumberReader(Reader in)
in
- A Reader object to provide the underlying streampublic LineNumberReader(Reader in, int sz)
in
- A Reader object to provide the underlying streamsz
- An int specifying the size of the bufferpublic void setLineNumber(int lineNumber)
lineNumber
- An int specifying the line numberpublic int getLineNumber()
public int read() throws IOException
read
in class BufferedReader
IOException
- If an I/O error occurspublic int read(char[] cbuf, int off, int len) throws IOException
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.
read
in class BufferedReader
cbuf
- Destination bufferoff
- Offset at which to start storing characterslen
- Maximum number of characters to readIndexOutOfBoundsException
- If off
is negative, or len
is negative, or len
is greater than cbuf.length - off
IOException
- If an I/O error occurspublic String readLine() throws IOException
readLine
in class BufferedReader
null
if the end of the stream has been reachedIOException
- If an I/O error occurspublic void mark(int readAheadLimit) throws IOException
mark
in class BufferedReader
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.IOException
- If an I/O error occurspublic void reset() throws IOException
reset
in class BufferedReader
IOException
- If the stream has not been marked, or if the mark has been invalidated
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Documentation extracted from Debian's OpenJDK Development Kit package.
Licensed under the GNU General Public License, version 2, with the Classpath Exception.
Various third party code in OpenJDK is licensed under different licenses (see Debian package).
Java and OpenJDK are trademarks or registered trademarks of Oracle and/or its affiliates.
https://docs.oracle.com/en/java/javase/21/docs/api/java.base/java/io/LineNumberReader.html