com.prosysopc.ua.stack.utils.bytebuffer

Class ByteQueue

java.lang.Object

com.prosysopc.ua.stack.utils.bytebuffer.ByteQueue

public class ByteQueue
extends Object

Byte Queue is a LIFO queue of bytes. It uses ByteBuffers as back-end for data. There are two incremental memory pointers, read and write position. Write position returns the number of bytes written to the queue, and read bytes read. ByteQueue allocates new memory as required in chunks.

Constructor Summary

Constructors

Constructor and Description
ByteQueue() Construct new byte queue usign default allocation size.
ByteQueue(int chunkSize) Construct new byte queue.

Method Summary

Modifier and Type	Method and Description
void	clear() Clears bytes and resets all pointers.
void	get(byte[] buf) Read from buf.
void	get(byte[] buf, int off, int len) Read from buf.
void	get(ByteBuffer dst) Reads to dst remaining bytes.
void	get(ByteBuffer dst, int length) Reads to dst.
ByteBuffer	get(int len) Read bytes (Efficient).
void	getAvailable(ByteBuffer dst) Reads as much as there is available and dst has remaining allocation.
ByteBufferFactory	getByteBufferFactory() Get byte buffer factory.
long	getBytesRead() Get the total number of bytes read from the queue.
long	getBytesWritten() Get the total number of bytes written to the queue.
ByteBuffer[]	getChunks(int len) Reads bytes.
int	getChunkSize() Get the block size of back-end chunks.
ByteBuffer	getReadChunk() Expose the a byte buffer of backend.
int	getWriteableBytesRemaining() Get the number of bytes remaining for write.
ByteBuffer	getWriteChunk() Exposes internal bytebuffer of this object.
long	getWriteLimit() Get writable bytes limit.
boolean	hasRemaining() hasRemaining.
boolean	isEmpty() Is buffer empty.
void	offer(ByteBuffer buf) Offers a byte buffer object for the queue.
void	omitAll() Clears queue and moves read pointer to written pointer.
ByteOrder	order() Get byte order.
void	order(ByteOrder order) Set byte order.
void	peek(byte[] buf) Peek data, read without moving read pointer.
void	peek(byte[] buf, int off, int len) Peek data, read without moving read pointer.
void	peek(ByteBuffer dst) Peeks to dst.
ByteBuffer	peek(int len) Peek, read without moving read pointer.
void	peekAvailable(ByteBuffer dst) Peek available data.
ByteBuffer[]	peekChunks(int len) Peeks given number of bytes.
void	put(byte value) put.
void	put(byte[] buf) Write bytes.
void	put(byte[] buf, int off, int len) Write bytes.
void	put(ByteBuffer src) Write remaining bytes of src.
void	put(ByteBuffer src, int length) Write remaining bytes of src.
long	remaining() Get the number of readable bytes.
void	setByteBufferFactory(ByteBufferFactory factory) Set byte buffer constructor.
void	setChunkSize(int chunkSize) Set the block size of back-end chunks.
void	setWriteLimit(long writeLimit) Set writable bytes limit.
void	skip(int bytes) Omit data by moving read pointer forward.
String	toString()

Methods inherited from class java.lang.Object

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

Constructor Detail

ByteQueue

public ByteQueue()

Construct new byte queue usign default allocation size.

ByteQueue

public ByteQueue(int chunkSize)

Construct new byte queue.

Parameters:

chunkSize - allocation size for new memory chunks

Method Detail

clear

public void clear()

Clears bytes and resets all pointers.

get

public void get(byte[] buf)
         throws BufferUnderflowException

Read from buf.

Parameters:

buf - buf to be filled

Throws:

BufferUnderflowException - if any.

get

public void get(byte[] buf,
                int off,
                int len)

Read from buf.

Parameters:

buf - an array of byte.

off - a int.

len - a int.

Throws:

BufferUnderflowException - if any.

get

public void get(ByteBuffer dst)
         throws BufferUnderflowException

Reads to dst remaining bytes.

Parameters:

dst - a ByteBuffer object.

Throws:

BufferUnderflowException - if any.

get

public void get(ByteBuffer dst,
                int length)
         throws BufferUnderflowException

Reads to dst.

Parameters:

dst - a ByteBuffer object.

length - a int.

Throws:

BufferUnderflowException - if any.

get

public ByteBuffer get(int len)
               throws BufferUnderflowException

Read bytes (Efficient). This implementation copies memory only if the requested data is span over several ByteBuffers in the back-end.

Parameters:

len - a int.

Returns:

ByteBuffer containing read data

Throws:

BufferUnderflowException - if any.

getAvailable

public void getAvailable(ByteBuffer dst)

Reads as much as there is available and dst has remaining allocation.

Parameters:

dst - a ByteBuffer object.

getByteBufferFactory

public ByteBufferFactory getByteBufferFactory()

Get byte buffer factory.

Returns:

byte buffer factory.

getBytesRead

public long getBytesRead()

Get the total number of bytes read from the queue.

Returns:

the total number of bytes read from the queue

getBytesWritten

public long getBytesWritten()

Get the total number of bytes written to the queue.

Returns:

the total number of bytes written to the queue

getChunks

public ByteBuffer[] getChunks(int len)
                       throws BufferUnderflowException

Reads bytes. This implementation does not copy memory.

Parameters:

len - number of bytes to read

Returns:

byte buffer array

Throws:

BufferUnderflowException - if any.

getChunkSize

public int getChunkSize()

Get the block size of back-end chunks.

Returns:

chunk size

getReadChunk

public ByteBuffer getReadChunk()

Expose the a byte buffer of backend. Moving the position of this byte buffer, moves the byte queue aswell.

Returns:

active read byte buffer or null

getWriteableBytesRemaining

public int getWriteableBytesRemaining()

Get the number of bytes remaining for write.

Returns:

bytes remaining

getWriteChunk

public ByteBuffer getWriteChunk()

Exposes internal bytebuffer of this object. Writing to this bytebuffer moves the pointer in this bytequeue aswell.

Returns:

returns a chunk with atleast 1 writeable byte

getWriteLimit

public long getWriteLimit()

Get writable bytes limit.

Returns:

writeable bytes constraint or Long.MAX_VALUE

hasRemaining

public boolean hasRemaining()

hasRemaining.

Returns:

a boolean.

isEmpty

public boolean isEmpty()

Is buffer empty.

Returns:

true if buffer is empty

offer

public void offer(ByteBuffer buf)
           throws BufferOverflowException

Offers a byte buffer object for the queue. The remaining bytes of buf are added to the queue. ByteQueue takes the ownership of buf.

Parameters:

buf - buffer to write

Throws:

BufferOverflowException - write limit exeeded

omitAll

public void omitAll()

Clears queue and moves read pointer to written pointer.

order

public ByteOrder order()

Get byte order.

Returns:

the byte order

order

public void order(ByteOrder order)

Set byte order.

Parameters:

order - a ByteOrder object.

peek

public void peek(byte[] buf)
          throws BufferUnderflowException

Peek data, read without moving read pointer.

Parameters:

buf - an array of byte.

Throws:

BufferUnderflowException - if any.

peek

public void peek(byte[] buf,
                 int off,
                 int len)
          throws BufferUnderflowException

Peek data, read without moving read pointer.

Parameters:

buf - an array of byte.

off - a int.

len - a int.

Throws:

BufferUnderflowException - if any.

peek

public void peek(ByteBuffer dst)
          throws BufferUnderflowException

Peeks to dst.

Parameters:

dst - a ByteBuffer object.

Throws:

BufferUnderflowException - if any.

peek

public ByteBuffer peek(int len)
                throws BufferUnderflowException

Peek, read without moving read pointer.

Parameters:

len - a int.

Returns:

a byte buffer containing the peeked bytes

Throws:

BufferUnderflowException - if any.

peekAvailable

public void peekAvailable(ByteBuffer dst)

Peek available data.

Parameters:

dst - a ByteBuffer object.

peekChunks

public ByteBuffer[] peekChunks(int len)
                        throws BufferUnderflowException

Peeks given number of bytes. This method does not copy memory.

Parameters:

len - a int.

Returns:

array of buffers.

Throws:

BufferUnderflowException - if any.

put

public void put(byte value)

put.

Parameters:

value - a byte.

put

public void put(byte[] buf)
         throws BufferOverflowException

Write bytes.

Parameters:

buf - bytes to write

Throws:

BufferOverflowException - write limit exeeded

put

public void put(byte[] buf,
                int off,
                int len)
         throws BufferOverflowException

Write bytes.

Parameters:

buf - bytes

off - offset

len - length

Throws:

BufferOverflowException - if any.

put

public void put(ByteBuffer src)

Write remaining bytes of src.

Parameters:

src - a ByteBuffer object.

Throws:

BufferOverflowException - write limit exeeded

put

public void put(ByteBuffer src,
                int length)

Write remaining bytes of src.

Parameters:

src - a ByteBuffer object.

length - a int.

Throws:

BufferOverflowException - write limit exeeded

remaining

public long remaining()

Get the number of readable bytes.

Returns:

number of readable bytes.

setByteBufferFactory

public void setByteBufferFactory(ByteBufferFactory factory)

Set byte buffer constructor. The constructed buffers may be larger than requested but remaining bytes must be the requested amount.

Parameters:

factory - a ByteBufferFactory object.

setChunkSize

public void setChunkSize(int chunkSize)

Set the block size of back-end chunks.

Parameters:

chunkSize - a int.

setWriteLimit

public void setWriteLimit(long writeLimit)

Set writable bytes limit.

Parameters:

writeLimit - new writeable bytes constraint

skip

public void skip(int bytes)
          throws BufferOverflowException

Omit data by moving read pointer forward.

Parameters:

bytes - to omit

Throws:

BufferOverflowException - if any.

toString

public String toString()

Overrides:

toString in class Object