This documentation differs from the official API. Jadeite adds extra features to the API including: variable font sizes, constructions examples, placeholders for classes and methods, and auto-generated “See Also” links. Additionally it is missing some items found in standard Javadoc documentation, including: generics type information, “Deprecated” tags and comments, “See Also” links, along with other minor differences. Please send any questions or feedback to bam@cs.cmu.edu.


java.io
class LineNumberInputStream

java.lang.Object extended by java.io.InputStream extended by java.io.FilterInputStream extended by java.io.LineNumberInputStream
All Implemented Interfaces:
Closeable

Most common way to construct:

FileInputStream inFile = …;

LineNumberInputStream inLines = new LineNumberInputStream(inFile);

Based on 14 examples


public class LineNumberInputStream
extends FilterInputStream

This class is an input stream filter that provides the added functionality of keeping track of the current line number.

A line is a sequence of bytes ending with a carriage return character ('\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.

See Also (auto-generated):

BufferedReader

DataInputStream

FileInputStream


Field Summary
 
Fields inherited from class java.io.FilterInputStream
in
 
Constructor Summary

          Constructs a newline number input stream that reads its input from the specified input stream.
 
Method Summary
 int

          Returns the number of bytes that can be read from this input stream without blocking.
 int

          Returns the current line number.
 void
mark(int readlimit)

          Marks the current position in this input stream.
 int

          Reads the next byte of data from this input stream.
 int
read(byte[] b, int off, int len)

          Reads up to len bytes of data from this input stream into an array of bytes.
 void

          Repositions this stream to the position at the time the mark method was last called on this input stream.
 void
setLineNumber(int lineNumber)

          Sets the line number to the specified argument.
 long
skip(long n)

          Skips over and discards n bytes of data from this input stream.
 
Methods inherited from class java.io.FilterInputStream
available, close, mark, markSupported, read, read, read, reset, skip
 
Methods inherited from class java.io.InputStream
available, close, mark, markSupported, read, read, read, reset, skip
 
Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
 

Constructor Detail

LineNumberInputStream

public LineNumberInputStream(InputStream in)
Constructs a newline number input stream that reads its input from the specified input stream.

Parameters:
in - the underlying input stream.
Method Detail

available

public int available()
              throws IOException
Returns the number of bytes that can be read from this input stream without blocking.

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 '\r' and '\n', which are converted to just k/2 '\n' characters.

Overrides:
available in class FilterInputStream
Returns:
the number of bytes that can be read from this input stream without blocking.
Throws:
IOException - if an I/O error occurs.

getLineNumber

public int getLineNumber()
Returns the current line number.

Returns:
the current line number.

mark

public void mark(int readlimit)
Marks the current position in this input stream. A subsequent call to the reset method repositions this stream at the last marked position so that subsequent reads re-read the same bytes.

The mark method of LineNumberInputStream remembers the current line number in a private variable, and then calls the mark method of the underlying input stream.

Overrides:
mark in class FilterInputStream
Parameters:
readlimit - the maximum limit of bytes that can be read before the mark position becomes invalid.

read

public int read()
         throws IOException
Reads the next byte of data from this input stream. The value byte is returned as an int in the range 0 to 255. If no byte is available because the end of the stream has been reached, the value -1 is returned. This method blocks until input data is available, the end of the stream is detected, or an exception is thrown.

The read method of LineNumberInputStream calls the read 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.

Overrides:
read in class FilterInputStream
Returns:
the next byte of data, or -1 if the end of this stream is reached.
Throws:
IOException - if an I/O error occurs.

read

public int read(byte[] b,
                int off,
                int len)
         throws IOException
Reads up to len bytes of data from this input stream into an array of bytes. This method blocks until some input is available.

The read method of LineNumberInputStream repeatedly calls the read method of zero arguments to fill in the byte array.

Overrides:
read in class FilterInputStream
Parameters:
b - the buffer into which the data is read.
off - the start offset of the data.
len - the maximum number of bytes read.
Returns:
the total number of bytes read into the buffer, or -1 if there is no more data because the end of this stream has been reached.
Throws:
IOException - if an I/O error occurs.

reset

public void reset()
           throws IOException
Repositions this stream to the position at the time the mark method was last called on this input stream.

The 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.

Overrides:
reset in class FilterInputStream
Throws:
IOException - if an I/O error occurs.

setLineNumber

public void setLineNumber(int lineNumber)
Sets the line number to the specified argument.

Parameters:
lineNumber - the new line number.

skip

public long skip(long n)
          throws IOException
Skips over and discards n bytes of data from this input stream. The skip method 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 n is negative, no bytes are skipped.

The skip method of LineNumberInputStream creates a byte array and then repeatedly reads into it until n bytes have been read or the end of the stream has been reached.

Overrides:
skip in class FilterInputStream
Parameters:
n - the number of bytes to be skipped.
Returns:
the actual number of bytes skipped.
Throws:
IOException - if an I/O error occurs.


This documentation differs from the official API. Jadeite adds extra features to the API including: variable font sizes, constructions examples, placeholders for classes and methods, and auto-generated “See Also” links. Additionally it is missing some items found in standard Javadoc documentation, including: generics type information, “Deprecated” tags and comments, “See Also” links, along with other minor differences. Please send any questions or feedback to bam@cs.cmu.edu.
This page displays the Jadeite version of the documention, which is derived from the offical documentation that contains this copyright notice:
Copyright 2008 Sun Microsystems, Inc. All rights reserved. Use is subject to license terms. Also see the documentation redistribution policy.
The official Sun™ documentation can be found here at http://java.sun.com/javase/6/docs/api/.