@Deprecated public class LineNumberInputStream extends FilterInputStream
A line is a sequence of bytes ending with a carriage return
'\r'), a newline character
'\n'), or a carriage return character followed
immediately by a linefeed character. In all three cases, the line
terminating character(s) are returned as a single newline character.
The line number begins at
0, and is incremented by
1 when a
read returns a newline character.
|Constructor and Description|
Constructs a newline number input stream that reads its input from the specified input stream.
|Modifier and Type||Method and Description|
Returns the number of bytes that can be read from this input stream without blocking.
Returns the current line number.
Marks the current position in this input stream.
Reads the next byte of data from this input stream.
Reads up to
Repositions this stream to the position at the time the
Sets the line number to the specified argument.
Skips over and discards
public LineNumberInputStream(InputStream in)
in- the underlying input stream.
public int read() throws IOException
intin the range
255. If no byte is available because the end of the stream has been reached, the value
-1is returned. This method blocks until input data is available, the end of the stream is detected, or an exception is thrown.
read method of
LineNumberInputStream calls the
method of the underlying input stream. It checks for carriage
returns and newline characters in the input, and modifies the
current line number as appropriate. A carriage-return character or
a carriage return followed by a newline character are both
converted into a single newline character.
public int read(byte b, int off, int len) throws IOException
lenbytes of data from this input stream into an array of bytes. This method blocks until some input is available.
read method of
LineNumberInputStream repeatedly calls the
read method of zero arguments to fill in the byte array.
b- the buffer into which the data is read.
off- the start offset of the data.
len- the maximum number of bytes read.
-1if there is no more data because the end of this stream has been reached.
IOException- if an I/O error occurs.
public long skip(long n) throws IOException
nbytes of data from this input stream. The
skipmethod may, for a variety of reasons, end up skipping over some smaller number of bytes, possibly
0. The actual number of bytes skipped is returned. If
nis negative, no bytes are skipped.
skip method of
a byte array and then repeatedly reads into it until
n bytes have been read or the end of the stream has
public void setLineNumber(int lineNumber)
lineNumber- the new line number.
public int getLineNumber()
public int available() throws IOException
Note that if the underlying input stream is able to supply
k input characters without blocking, the
LineNumberInputStream can guarantee only to provide
k/2 characters without blocking, because the
k characters from the underlying input stream might
consist of k/2 pairs of
'\n', which are converted to just
public void mark(int readlimit)
resetmethod repositions this stream at the last marked position so that subsequent reads re-read the same bytes.
mark method of
LineNumberInputStream remembers the current line
number in a private variable, and then calls the
method of the underlying input stream.
public void reset() throws IOException
markmethod was last called on this input stream.
reset method of
LineNumberInputStream resets the line number to be
the line number at the time the
mark method was
called, and then calls the
reset method of the
underlying input stream.
Stream marks are intended to be used in situations where you need to read ahead a little to see what's in the stream. Often this is most easily done by invoking some general parser. If the stream is of the type handled by the parser, it just chugs along happily. If the stream is not of that type, the parser should toss an exception when it fails, which, if it happens within readlimit bytes, allows the outer code to reset the stream and try another parser.