java.io
public class LineNumberReader extends BufferedReader
Reader except that it
counts line numbers, and canonicalizes newline characters. As data
is read, whenever the char sequences "\r", "\n", or "\r\n" are encountered,
the running line count is incremeted by one. Additionally, the whatever
line termination sequence was encountered will be converted to a "\n"
char. Note that this class numbers lines from 0. When the first
line terminator is encountered, the line number is incremented to 1, and
so on. Also note that actual "\r" and "\n" characters are looked for.
The system dependent line separator sequence is ignored.
This class counts only line termination characters. If the last line read from the stream does not end in a line termination sequence, it will not be counted as a line.
UNKNOWN: December 28, 2003.
| Constructor Summary | |
|---|---|
| LineNumberReader(Reader in)
Create a new LineNumberReader that reads from the
specified subordinate Reader. | |
| LineNumberReader(Reader in, int size)
This method initializes a new LineNumberReader to read
from the specified subordinate Reader using the specified
read buffer size.
| |
| Method Summary | |
|---|---|
| int | getLineNumber()
This method returns the current line number
|
| void | mark(int readLimit)
This method marks a position in the input to which the stream can be
"reset" char calling the reset() method. |
| int | read()
This method reads an unsigned char from the input stream and returns it
as an int in the range of 0-65535. |
| int | read(char[] buf, int offset, int count)
This method reads chars from a stream and stores them into a caller
supplied buffer. |
| String | readLine()
This method reads a line of text from the input stream and returns
it as a String. |
| void | reset()
This method resets a stream to the point where the mark()
method
was called. |
| void | setLineNumber(int lineNumber)
This method sets the current line number to the specified value.
|
| long | skip(long count)
This method skips over characters in the stream. |
LineNumberReader that reads from the
specified subordinate Reader. A default 8K char sized
buffer will be used for reads.
Parameters: in The subordinate Reader to read from
LineNumberReader to read
from the specified subordinate Reader using the specified
read buffer size.
Parameters: in The subordinate Reader to read from size The buffer size to use for reading
Returns: The current line number
reset() method. The parameter
readlimit is the number of chars that can be read from the
stream after setting the mark before the mark becomes invalid. For
example, if mark() is called with a read limit of 10,
then when
11 chars of data are read from the stream before the reset()
method is called, then the mark is invalid and the stream object
instance is not required to remember the mark.
In this class, this method will remember the current line number as well
as the current position in the stream. When the reset()
method
is called, the line number will be restored to the saved line number in
addition to the stream position.
Parameters: readLimit The number of chars that can be read before the mark becomes invalid
Throws: IOException If an error occurs
Note that if a line termination sequence is encountered (ie, "\r", "\n", or "\r\n") then that line termination sequence is converted to a single "\n" value which is returned from this method. This means that it is possible this method reads two chars from the subordinate stream instead of just one.
Note that this method will block until a char of data is available to be read.
Returns: The char read or -1 if end of stream
Throws: IOException If an error occurs
offset into
the buffer and attemps to read len chars. This method can
return before reading the number of chars requested. The actual number
of chars read is returned as an int. A -1 is returned to indicated the
end of the stream.
This method will block until some data can be read.
Note that if a line termination sequence is encountered (ie, "\r", "\n", or "\r\n") then that line termination sequence is converted to a single "\n" value which is stored in the buffer. Only a single char is counted towards the number of chars read in this case.
Parameters: buf The array into which the chars read should be stored offset The offset into the array to start storing chars count The requested number of chars to read
Returns: The actual number of chars read, or -1 if end of stream
Throws: IOException If an error occurs. NullPointerException If buf is null (in any case). IndexOutOfBoundsException If buffer parameters (offset and count) lies outside of the buffer capacity.
String. A line is considered to be terminated
by a "\r", "\n", or "\r\n" sequence, not by the system dependent line
separator.
Returns: The line read as a String or null
if end of stream.
Throws: IOException If an error occurs
mark()
method
was called. Any chars that were read after the mark point was set will
be re-read during subsequent reads.
In this class, this method will also restore the line number that was
current when the mark() method was called.
Throws: IOException If an error occurs
Parameters: lineNumber The new line number
Parameters: count The specified number of chars to skip.
Returns: The actual number of chars skipped.
Throws: IOException If an error occurs