java.lang.Object | +--java.io.InputStream | +--java.io.FilterInputStream | +--java.io.LineNumberInputStream
LineNumberInputStream(java.io.InputStream in) Create a new |
int | available() This method returns the number of bytes that can be read from the stream before the stream can block. |
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" byte calling the |
int | read() This method reads an unsigned byte from the input stream and returns it as an int in the range of 0-255. |
int | read(byte[] b, int off, int len) This method reads bytes from a stream and stores them into a caller supplied buffer. |
void | reset() This method resets a stream to the point where the
|
void | setLineNumber(int lineNumber) This method sets the current line number to the specified value. |
long | skip(long n) This method skips up to the requested number of bytes in the input stream. |
public LineNumberInputStream(java.io.InputStream in)
LineNumberInputStream
that reads from the
specified subordinate InputStream
in
- The subordinate InputStream
to read frompublic int available()
InputStream
might return
only "\r\n" characters, which are replaced by a single "\n"
character by the read()
method of this class. So
this method can only guarantee that in.available() /
2
bytes can actually be read before blocking. In
practice, considerably more bytes might be read before blocking
Note that the stream may not block if additional bytes beyond the count returned by this method are read.
IOException
- If an error occurspublic int getLineNumber()
public void mark(int readlimit)
reset()
method. The
parameter readlimit
is the number of bytes 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 bytes 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.
This method only works if the subordinate stream supports mark/reset functionality.
readlimit
- The number of bytes that can be read before the
mark becomes invalidpublic int 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 returned from this method. This means that it is possible this method reads two bytes from the subordinate stream instead of just one.
Note that this method will block until a byte of data is available to be read.
IOException
- If an error occurspublic int read(byte[] b, int off, int len)
offset
into
the buffer and attemps to read len
bytes. This method can
return before reading the number of bytes requested. The actual number
of bytes 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 byte is counted towards the number of bytes read in this case.
b
- The array into which the bytes read should be storedoff
- The offset into the array to start storing byteslen
- The requested number of bytes to readIOException
- If an error occurs.public void reset()
mark()
method was called. Any bytes 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.
This method only works if the subordinate stream supports mark/reset functionality.
IOException
- If an error occurspublic void setLineNumber(int lineNumber)
lineNumber
- The new line numberpublic long skip(long n)
n
- requested number of bytes to skip.IOException
- If an error occurs.
InputStream
except that it counts line numbers, and canonicalizes newline characters. As data is read, whenever the byte 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" byte. 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.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.
Note that since this class operates as a filter on an underlying stream, it has the same mark/reset functionality as the underlying stream. The
mark()
andreset()
methods in this class handle line numbers correctly. Calling