org.apache.tika.io

Class TailStream

java.lang.Object

java.io.InputStream

java.io.FilterInputStream

org.apache.tika.io.TailStream

All Implemented Interfaces:

Closeable, AutoCloseable

public class TailStream
extends FilterInputStream

A specialized input stream implementation which records the last portion read from an underlying stream.

This stream implementation is useful to deal with information which is known to be located at the end of a stream (e.g. ID3 v1 tags). While reading bytes from the underlying stream, a given number of bytes is kept in an internal buffer. This buffer can then be queried after the whole stream was read. It contains the last bytes read from the original input stream.

Field Summary

Fields inherited from class java.io.FilterInputStream

in

Constructor Summary

Constructors

Constructor and Description
TailStream(InputStream in, int size) Creates a new instance of TailStream.

Method Summary

Modifier and Type	Method and Description
byte[]	getTail() Returns an array with the last data read from the underlying stream.
void	mark(int limit) This implementation saves the internal state including the content of the tail buffer so that it can be restored when ''reset()'' is called later.
int	read() This implementation adds the read byte to the internal tail buffer.
int	read(byte[] buf) This implementation delegates to the underlying stream and then adds the correct portion of the read buffer to the internal tail buffer.
int	read(byte[] buf, int ofs, int length) This implementation delegates to the underlying stream and then adds the correct portion of the read buffer to the internal tail buffer.
void	reset() This implementation restores this stream's state to the state when ''mark()'' was called the last time.
long	skip(long n) This implementation delegates to the read() method to ensure that the tail buffer is also filled if data is skipped.

Methods inherited from class java.io.FilterInputStream

available, close, markSupported

Methods inherited from class java.lang.Object

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

Constructor Detail

TailStream

public TailStream(InputStream in,
                  int size)

Creates a new instance of TailStream.

Parameters:

in - the underlying input stream

size - the size of the tail buffer

Method Detail

read

public int read()
         throws IOException

This implementation adds the read byte to the internal tail buffer.

Overrides:

read in class FilterInputStream

Throws:

IOException

read

public int read(byte[] buf)
         throws IOException

This implementation delegates to the underlying stream and then adds the correct portion of the read buffer to the internal tail buffer.

Overrides:

read in class FilterInputStream

Throws:

IOException

read

public int read(byte[] buf,
                int ofs,
                int length)
         throws IOException

This implementation delegates to the underlying stream and then adds the correct portion of the read buffer to the internal tail buffer.

Overrides:

read in class FilterInputStream

Throws:

IOException

skip

public long skip(long n)
          throws IOException

This implementation delegates to the read() method to ensure that the tail buffer is also filled if data is skipped.

Overrides:

skip in class FilterInputStream

Throws:

IOException

mark

public void mark(int limit)

This implementation saves the internal state including the content of the tail buffer so that it can be restored when ''reset()'' is called later.

Overrides:

mark in class FilterInputStream

reset

public void reset()

This implementation restores this stream's state to the state when ''mark()'' was called the last time. If ''mark()'' has not been called before, this method has no effect.

Overrides:

reset in class FilterInputStream

getTail

public byte[] getTail()

Returns an array with the last data read from the underlying stream. If the underlying stream contained more data than the ''tailSize'' constructor argument, the returned array has a length of ''tailSize''. Otherwise, its length equals the number of bytes read.

Returns:

an array with the last data read from the underlying stream