org.terrier.compression
Class MemoryLinkedOutputStream

java.lang.Object
  java.io.OutputStream
      org.terrier.compression.MemoryLinkedOutputStream

All Implemented Interfaces:

java.io.Closeable, java.io.Flushable

public class MemoryLinkedOutputStream
extends java.io.OutputStream

This class implements an OutputStream that writes everything in memory, and never flushes the data to disk. It uses a Linked list of byte[] arrays, probably of different sizes, to keep track of the new allocations. This class needs more memory (the pointers) than the MemoryOutputStream class, but it avoids the reallocation of arrays in memory.

Author:

Roi Blanco

Field Summary

static int	DEFAULT_BUFFER_SIZE The default size of the internal buffer in bytes
protected MemoryLinkedOutputStream	next Reference to the linked structure

Constructor Summary

MemoryLinkedOutputStream()
Instanciates a MemoryLinkedOutputStream with the buffer size set to DEFAULT_BUFFER_SIZE

MemoryLinkedOutputStream(int bufferSize)
Instanciates a MemoryLinkedOutputStream specifying the buffer size.

Method Summary

void	beginRead() Sets the structure for reading
void	flush() Empty method
byte[]	getBuffer()
MemoryLinkedOutputStream	getNext()
int	getPos()
boolean	isNext()
void	nextBuffer() Moves the pointer to the next buffer (reading)
void	write(int b) Writes a byte into the current buffer.

Methods inherited from class java.io.OutputStream

close, write, 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

See Also:

Constant Field Values

next

protected MemoryLinkedOutputStream next

Reference to the linked structure

Constructor Detail

MemoryLinkedOutputStream

public MemoryLinkedOutputStream()

Instanciates a MemoryLinkedOutputStream with the buffer size set to DEFAULT_BUFFER_SIZE

MemoryLinkedOutputStream

public MemoryLinkedOutputStream(int bufferSize)

Instanciates a MemoryLinkedOutputStream specifying the buffer size.

Parameters:

bufferSize - int size of the first buffer

Method Detail

getNext

public MemoryLinkedOutputStream getNext()

Returns:

the next buffer in the list (next of current)

getPos

public int getPos()

Returns:

the position in the current buffer.

beginRead

public void beginRead()

Sets the structure for reading

write

public void write(int b)
           throws java.io.IOException

Writes a byte into the current buffer. If it fills the buffer, it moves to the next one (doubling the capacity).

Specified by:

write in class java.io.OutputStream

Parameters:

b - the byte to write

Throws:

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

getBuffer

public byte[] getBuffer()

Returns:

the current byte[] buffer.

isNext

public boolean isNext()

Returns:

true if there is a buffer next to the current one.

nextBuffer

public void nextBuffer()

Moves the pointer to the next buffer (reading)

flush

public void flush()
           throws java.io.IOException

Empty method

Specified by:

flush in interface java.io.Flushable

Overrides:

flush in class java.io.OutputStream

Throws:

java.io.IOException