it.unimi.dsi.fastutil.io

Class FastBufferedOutputStream

java.lang.Object

java.io.OutputStream

it.unimi.dsi.fastutil.io.MeasurableOutputStream

it.unimi.dsi.fastutil.io.FastBufferedOutputStream

All Implemented Interfaces:

MeasurableStream, RepositionableStream, Closeable, Flushable, AutoCloseable

public class FastBufferedOutputStream
extends MeasurableOutputStream
implements RepositionableStream

Lightweight, unsynchronized output stream buffering class with measurability and repositionability.

This class provides buffering for output streams, but it does so with purposes and an internal logic that are radically different from the ones adopted in BufferedOutputStream. The main features follow.

• All methods are unsychronized.

• As an additional feature, this class implements the RepositionableStream and MeasurableStream interfaces. An instance of this class will try to cast the underlying byte stream to a RepositionableStream and to fetch by reflection the FileChannel underlying the given output stream, in this order. If either reference can be successfully fetched, you can use position(long) to reposition the stream. Much in the same way, an instance of this class will try to cast the the underlying byte stream to a MeasurableStream, and if this operation is successful, or if a FileChannel can be detected, then position() and length() will work as expected.

Since:

4.4

Field Summary

Fields

Modifier and Type	Field and Description
protected int	avail The number of buffer bytes available starting from pos (it must be always equal to buffer.length - pos).
protected byte[]	buffer The internal buffer.
static int	DEFAULT_BUFFER_SIZE The default size of the internal buffer in bytes (8Ki).
protected OutputStream	os The underlying output stream.
protected int	pos The current position in the buffer.

Constructor Summary

Constructors

Constructor and Description
FastBufferedOutputStream(OutputStream os) Creates a new fast buffered ouptut stream by wrapping a given output stream with a buffer of DEFAULT_BUFFER_SIZE bytes.
FastBufferedOutputStream(OutputStream os, int bufferSize) Creates a new fast buffered output stream by wrapping a given output stream with a given buffer size.

Method Summary

Methods

Modifier and Type	Method and Description
void	close()
void	flush()
long	length() Returns the length of the underlying output stream, if it is measurable.
long	position() Returns the current stream position.
void	position(long newPosition) Repositions the stream.
void	write(byte[] b, int offset, int length)
void	write(int b)

Methods inherited from class java.io.OutputStream

write

Methods inherited from class java.lang.Object

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

Field Detail

DEFAULT_BUFFER_SIZE

public static final int DEFAULT_BUFFER_SIZE

The default size of the internal buffer in bytes (8Ki).

See Also:

Constant Field Values

buffer

protected byte[] buffer

The internal buffer.

pos

protected int pos

The current position in the buffer.

avail

protected int avail

The number of buffer bytes available starting from pos (it must be always equal to buffer.length - pos).

os

protected OutputStream os

The underlying output stream.

Constructor Detail

FastBufferedOutputStream

public FastBufferedOutputStream(OutputStream os,
                        int bufferSize)

Creates a new fast buffered output stream by wrapping a given output stream with a given buffer size.

Parameters:

os - an output stream to wrap.

bufferSize - the size in bytes of the internal buffer.

FastBufferedOutputStream

public FastBufferedOutputStream(OutputStream os)

Creates a new fast buffered ouptut stream by wrapping a given output stream with a buffer of DEFAULT_BUFFER_SIZE bytes.

Parameters:

os - an output stream to wrap.

Method Detail

write

public void write(int b)
           throws IOException

Specified by:

write in class OutputStream

Throws:

IOException

write

public void write(byte[] b,
         int offset,
         int length)
           throws IOException

Overrides:

write in class OutputStream

Throws:

IOException

flush

public void flush()
           throws IOException

Specified by:

flush in interface Flushable

Overrides:

flush in class OutputStream

Throws:

IOException

close

public void close()
           throws IOException

Specified by:

close in interface Closeable

Specified by:

close in interface AutoCloseable

Overrides:

close in class OutputStream

Throws:

IOException

position

public long position()
              throws IOException

Description copied from interface: RepositionableStream

Returns the current stream position.

Specified by:

position in interface MeasurableStream

Specified by:

position in interface RepositionableStream

Returns:

the current stream position.

Throws:

IOException

position

public void position(long newPosition)
              throws IOException

Repositions the stream.

Note that this method performs a flush() before changing the underlying stream position.

Specified by:

position in interface RepositionableStream

Parameters:

newPosition - the new stream position.

Throws:

IOException

length

public long length()
            throws IOException

Returns the length of the underlying output stream, if it is measurable.

Note that this method performs a flush() before detecting the length.

Specified by:

length in interface MeasurableStream

Returns:

the length of the underlying output stream.

Throws:

UnsupportedOperationException - if the underlying output stream is not measurable and cannot provide a FileChannel.

IOException