com.groovemanager.tools
Class RingBuffer

java.lang.Object
  com.groovemanager.tools.RingBuffer

public class RingBuffer

extends java.lang.Object

A RingBuffer represents a buffer that has a read and a write position which are set back to 0 when the end is reached. Buffer underruns or overflows are avoided by only allowing writing or reading aslong as there are enough bytes available for the deired operation. As one can expect that reader and writer will be different threads, this implementation is synchronized where needed.

Author:

Manu Robledo

Field Summary

private int	granularity The granularity in which data must be read or written.
private boolean	open Indicates whether this buffer is in open state or not
private java.nio.ByteBuffer	readBuffer A view to the source buffer used for reading
private boolean	writeAhead When read and write position are the same, this value indicates, whether the buffer is filled completely (false) or emptied completely (true)
private java.nio.ByteBuffer	writeBuffer A view to the source buffer used for reading

Constructor Summary

RingBuffer(byte[] buffer, int offset, int length, int granularity)
Construct a new RingBuffer out of the specified part of the given byte array

RingBuffer(java.nio.ByteBuffer buffer, int granularity)
Construct a new RingBuffer out of the given buffer

Method Summary

void	close() Close this buffer
void	flush() Empty this buffer
boolean	isOpen() Tells whether this buffer is currently open or not
void	open() Open this buffer
int	read(byte[] b, int off, int len) Try to read len bytes from this buffer starting at the current position into b starting at position off.
int	readAvailable() Get the number of bytes currently available for reading
int	size() Get this buffer´s total size
int	write(byte[] b, int off, int len) Try to write len bytes from b starting at index off into this buffer starting at the current position.
int	writeAvailable() Get the number of bytes currently available for writing

Methods inherited from class java.lang.Object

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

Field Detail

granularity

private final int granularity

The granularity in which data must be read or written. Data will only be available in blocks of this value.

open

private boolean open

Indicates whether this buffer is in open state or not

readBuffer

private final java.nio.ByteBuffer readBuffer

A view to the source buffer used for reading

writeAhead

private boolean writeAhead

When read and write position are the same, this value indicates, whether the buffer is filled completely (false) or emptied completely (true)

writeBuffer

private final java.nio.ByteBuffer writeBuffer

A view to the source buffer used for reading

Constructor Detail

RingBuffer

public RingBuffer(byte[] buffer,
                  int offset,
                  int length,
                  int granularity)

Construct a new RingBuffer out of the specified part of the given byte array

Parameters:

buffer - The byte array that should be used as source of this buffer

offset - Start position inside the given array

length - The length of the buffer to create

granularity - The buffer granularity in bytes

RingBuffer

public RingBuffer(java.nio.ByteBuffer buffer,
                  int granularity)

Construct a new RingBuffer out of the given buffer

Parameters:

buffer - The buffer to be used as source for this ring buffer

granularity - The buffer granularity in bytes

Method Detail

close

public void close()

Close this buffer

flush

public void flush()

Empty this buffer

isOpen

public boolean isOpen()

Tells whether this buffer is currently open or not

Returns:

true, if this buffer is open, false otherwise

open

public void open()

Open this buffer

read

public int read(byte[] b,
                int off,
                int len)

Try to read len bytes from this buffer starting at the current position into b starting at position off. The currently avilable bytes will be read the number of bytes read will be returned.

Parameters:

b - The byte array to transfer the data to

off - The offset inside the target array

len - The number of bytes to read

Returns:

The number of bytes read

readAvailable

public int readAvailable()

Get the number of bytes currently available for reading

Returns:

The number of bytes avilable for reading

size

public int size()

Get this buffer´s total size

Returns:

This buffer´s total size in bytes

write

public int write(byte[] b,
                 int off,
                 int len)

Try to write len bytes from b starting at index off into this buffer starting at the current position. This method will not return before the given number of bytes has been written or the buffer has been closed. This means that if the given number of bytes can not be written at once, this methods waits until another thread empties the needed part of this buffer by reading from it.

Parameters:

b - The array containing the data to write

off - Start position inside the given array

len - The number of bytes to write

Returns:

The number of bytes written

writeAvailable

public int writeAvailable()

Get the number of bytes currently available for writing

Returns:

The number of bytes available for writing