com.jalios.io

Class LineDelimiterFilterInputStream

java.lang.Object

java.io.InputStream

java.io.FilterInputStream

com.jalios.io.LineDelimiterFilterInputStream

All Implemented Interfaces:

java.io.Closeable, java.lang.AutoCloseable

public class LineDelimiterFilterInputStream
extends java.io.FilterInputStream

This class is an input stream filter that provides the added functionality of converting all types of line delimiter into unix line delimiter '\n'.

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.

Since:

jcms-5.7.4

Field Summary

Fields

Modifier and Type	Field and Description
static java.lang.String	REVISION

Fields inherited from class java.io.FilterInputStream

in

Constructor Summary

Constructors

Constructor and Description
LineDelimiterFilterInputStream(java.io.InputStream in) Constructs a newline number input stream that reads its input from the specified input stream.

Method Summary

Methods

Modifier and Type	Method and Description
int	available() Returns the number of bytes that can be read from this input stream without blocking.
void	mark(int readlimit) Marks the current position in this input stream.
int	read() 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	reset() Repositions this stream to the position at the time the mark method was last called on this input stream.
long	skip(long n) Skips over and discards n bytes of data from this input stream.

Methods inherited from class java.io.FilterInputStream

close, markSupported, read

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

REVISION

public static final java.lang.String REVISION

See Also:

Constant Field Values

Constructor Detail

LineDelimiterFilterInputStream

public LineDelimiterFilterInputStream(java.io.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

read

public int read()
         throws java.io.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 LineDelimiterFilterInputStream calls the read method of the underlying input stream. It checks for carriage returns and newline characters in the input, 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 java.io.FilterInputStream

Returns:

the next byte of data, or -1 if the end of this stream is reached.

Throws:

java.io.IOException - if an I/O error occurs.

read

public int read(byte[] b,
       int off,
       int len)
         throws java.io.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 LineDelimiterFilterInputStream repeatedly calls the read method of zero arguments to fill in the byte array.

Overrides:

read in class java.io.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:

java.io.IOException - if an I/O error occurs.

See Also:

read()

skip

public long skip(long n)
          throws java.io.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 LineDelimiterFilterInputStream 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 java.io.FilterInputStream

Parameters:

n - the number of bytes to be skipped.

Returns:

the actual number of bytes skipped.

Throws:

java.io.IOException - if an I/O error occurs.

available

public int available()
              throws java.io.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 LineDelimiterFilterInputStream 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 java.io.FilterInputStream

Returns:

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

Throws:

java.io.IOException - if an I/O error occurs.

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

Overrides:

mark in class java.io.FilterInputStream

Parameters:

readlimit - the maximum limit of bytes that can be read before the mark position becomes invalid.

See Also:

reset()

reset

public void reset()
           throws java.io.IOException

Repositions this stream to the position at the time the mark method was last called on this input stream.

The reset method of LineDelimiterFilterInputStream resets the current line to be the line 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 java.io.FilterInputStream

Throws:

java.io.IOException - if an I/O error occurs.

See Also:

mark(int)