java.io

Class LineNumberInputStream

java.lang.Object

java.io.InputStream

java.io.FilterInputStream

java.io.LineNumberInputStream

All Implemented Interfaces:

Closeable, AutoCloseable

Deprecated.

Use LineNumberReader instead.

@Deprecated
public class LineNumberInputStream
extends FilterInputStream

Wraps an existing InputStream and counts the line terminators encountered while reading the data. Line numbering starts at 0. Recognized line terminator sequences are '\r', '\n' and "\r\n". When using read, line terminator sequences are always translated into '\n'.

Field Summary

Fields inherited from class java.io.FilterInputStream

in

Constructor Summary

Constructors

Constructor and Description
LineNumberInputStream(InputStream in) Deprecated. Constructs a new LineNumberInputStream on the InputStream in.

Method Summary

Modifier and Type	Method and Description
int	available() Deprecated. Returns an estimated number of bytes that can be read or skipped without blocking for more input.
int	getLineNumber() Deprecated. Returns the current line number for this stream.
void	mark(int readlimit) Deprecated. Sets a mark position in this stream.
int	read() Deprecated. Reads a single byte from the filtered stream and returns it as an integer in the range from 0 to 255.
int	read(byte[] buffer, int byteOffset, int byteCount) Deprecated. Reads up to byteCount bytes from the filtered stream and stores them in the byte array buffer starting at byteOffset.
void	reset() Deprecated. Resets this stream to the last marked location.
void	setLineNumber(int lineNumber) Deprecated. Sets the line number of this stream to the specified lineNumber.
long	skip(long byteCount) Deprecated. Skips count number of bytes in this stream.

Methods inherited from class java.io.FilterInputStream

close, markSupported

Methods inherited from class java.io.InputStream

nullInputStream, read, readAllBytes, readNBytes, readNBytes, transferTo

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)

Deprecated.

Constructs a new LineNumberInputStream on the InputStream in. Line numbers are counted for all data read from this stream.

Warning: passing a null source creates an invalid LineNumberInputStream. All operations on such a stream will fail.

Parameters:

in - The non-null input stream to count line numbers.

Method Detail

available

public int available()
              throws IOException

Deprecated.

Returns an estimated number of bytes that can be read or skipped without blocking for more input.

Note that this method provides such a weak guarantee that it is not very useful in practice.

Firstly, the guarantee is "without blocking for more input" rather than "without blocking": a read may still block waiting for I/O to complete — the guarantee is merely that it won't have to wait indefinitely for data to be written. The result of this method should not be used as a license to do I/O on a thread that shouldn't be blocked.

Secondly, the result is a conservative estimate and may be significantly smaller than the actual number of bytes available. In particular, an implementation that always returns 0 would be correct. In general, callers should only use this method if they'd be satisfied with treating the result as a boolean yes or no answer to the question "is there definitely data ready?".

Thirdly, the fact that a given number of bytes is "available" does not guarantee that a read or skip will actually read or skip that many bytes: they may read or skip fewer.

It is particularly important to realize that you must not use this method to size a container and assume that you can read the entirety of the stream without needing to resize the container. Such callers should probably write everything they read to a ByteArrayOutputStream and convert that to a byte array. Alternatively, if you're reading from a file, File.length() returns the current length of the file (though assuming the file's length can't change may be incorrect, reading a file is inherently racy).

The default implementation of this method in InputStream always returns 0. Subclasses should override this method if they are able to indicate the number of bytes available.

Note that the source stream may just be a sequence of "\r\n" bytes which are converted into '\n' by this stream. Therefore, available returns only in.available() / 2 bytes as result.

Overrides:

available in class FilterInputStream

Returns:

the estimated number of bytes available

Throws:

IOException - if this stream is closed or an error occurs

getLineNumber

public int getLineNumber()

Deprecated.

Returns the current line number for this stream. Numbering starts at 0.

Returns:

the current line number.

mark

public void mark(int readlimit)

Deprecated.

Sets a mark position in this stream. The parameter readlimit indicates how many bytes can be read before the mark is invalidated. Sending reset() will reposition this stream back to the marked position, provided that readlimit has not been surpassed. The line number count will also be reset to the last marked line number count.

This implementation sets a mark in the filtered stream.

Overrides:

mark in class FilterInputStream

Parameters:

readlimit - the number of bytes that can be read from this stream before the mark is invalidated.

See Also:

FilterInputStream.markSupported(), reset()

read

public int read()
         throws IOException

Deprecated.

Reads a single byte from the filtered stream and returns it as an integer in the range from 0 to 255. Returns -1 if the end of this stream has been reached.

The line number count is incremented if a line terminator is encountered. Recognized line terminator sequences are '\r', '\n' and "\r\n". Line terminator sequences are always translated into '\n'.

Overrides:

read in class FilterInputStream

Returns:

the byte read or -1 if the end of the filtered stream has been reached.

Throws:

IOException - if the stream is closed or another IOException occurs.

read

public int read(byte[] buffer,
                int byteOffset,
                int byteCount)
         throws IOException

Deprecated.

Reads up to byteCount bytes from the filtered stream and stores them in the byte array buffer starting at byteOffset. Returns the number of bytes actually read or -1 if no bytes have been read and the end of this stream has been reached.

The line number count is incremented if a line terminator is encountered. Recognized line terminator sequences are '\r', '\n' and "\r\n". Line terminator sequences are always translated into '\n'.

Overrides:

read in class FilterInputStream

Throws:

IndexOutOfBoundsException - if byteOffset < 0 || byteCount < 0 || byteOffset + byteCount > buffer.length.

IOException - if this stream is closed or another IOException occurs.

NullPointerException - if buffer == null.

reset

public void reset()
           throws IOException

Deprecated.

Resets this stream to the last marked location. It also resets the line count to what is was when this stream was marked.

Overrides:

reset in class FilterInputStream

Throws:

IOException - if this stream is already closed, no mark has been set or the mark is no longer valid because more than readlimit bytes have been read since setting the mark.

See Also:

mark(int), FilterInputStream.markSupported()

setLineNumber

public void setLineNumber(int lineNumber)

Deprecated.

Sets the line number of this stream to the specified lineNumber. Note that this may have side effects on the line number associated with the last marked position.

Parameters:

lineNumber - the new lineNumber value.

See Also:

mark(int), reset()

skip

public long skip(long byteCount)
          throws IOException

Deprecated.

Skips count number of bytes in this stream. Subsequent calls to read will not return these bytes unless reset is used. This implementation skips byteCount bytes in the filtered stream and increments the line number count whenever line terminator sequences are skipped.

Overrides:

skip in class FilterInputStream

Parameters:

byteCount - the number of bytes to skip.

Returns:

the number of bytes actually skipped.

Throws:

IOException - if this stream is closed or another IOException occurs.

See Also:

mark(int), read(), reset()