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com.tangosol.io
Class ByteArrayWriteBuffer

java.lang.Object
com.tangosol.io.AbstractWriteBuffer
com.tangosol.io.ByteArrayWriteBuffer

All Implemented Interfaces:

WriteBuffer

Direct Known Subclasses:

BinaryWriteBuffer

public class ByteArrayWriteBuffer

extends AbstractWriteBuffer

ByteArrayWriteBuffer is an implementation of WriteBuffer on a byte array. It is designed to support both fixed length buffers and resizable buffers.

This implementation is not intended to be thread safe.

Author:

cp 2005.03.24

Nested Class Summary

static class	ByteArrayWriteBuffer.Allocator Allocator is a WriteBufferPool implementation which allocates a new ByteArrayWriteBuffer on each request to the pool, and does not retain the returned buffer.
class	ByteArrayWriteBuffer.ByteArrayBufferOutput ByteArrayBufferOutput is an implementation of BufferOutput optimized for writing to the buffer's underlying byte array.

Nested classes/interfaces inherited from class com.tangosol.io.AbstractWriteBuffer

AbstractWriteBuffer.AbstractBufferOutput

Nested classes/interfaces inherited from interface com.tangosol.io.WriteBuffer

WriteBuffer.BufferOutput

Field Summary

protected byte[]	m_ab The byte array that holds the binary data.
protected ByteArrayReadBuffer	m_bufUnsafe Cached ReadBuffer to quickly provide an answer to getUnsafeReadBuffer().
protected int	m_cb Number of bytes in the byte array that have been written by this WriteBuffer.
protected int	m_cbMax Number of bytes that the byte array can be grown to.

Fields inherited from class com.tangosol.io.AbstractWriteBuffer

CHAR_BUF_MASK, CHAR_BUF_SIZE, m_achBuf, NO_BINARY, NO_BYTES

Constructor Summary

protected	ByteArrayWriteBuffer() Default constructor; intended only for use by subclasses.
	ByteArrayWriteBuffer(byte[] ab) Construct a ByteArrayWriteBuffer on a byte array.
	ByteArrayWriteBuffer(int cbCap) Construct an ByteArrayWriteBuffer with a certain initial capacity.
	ByteArrayWriteBuffer(int cbCap, int cbMax) Construct an ByteArrayWriteBuffer with a certain initial capacity and a certain maximum capacity.

Method Summary

protected void	checkBounds(int of, int cb) Validate the ranges for the passed bounds and make sure that the underlying array is big enough to handle them.
protected int	copyStream(int ofDest, InputStreaming stream, int cbMax) Store the remaining contents of the specified InputStreaming object at the specified offset within this buffer.
WriteBuffer.BufferOutput	getBufferOutput(int of) Get a BufferOutput object to write data to this buffer starting at a particular offset.
int	getCapacity() Determine the number of bytes that the buffer can hold without resizing itself.
int	getMaximumCapacity() Determine the maximum number of bytes that the buffer can hold.
byte[]	getRawByteArray() Obtain the byte array that this WriteBuffer uses.
ReadBuffer	getUnsafeReadBuffer() Get a ReadBuffer object to read data from this buffer.
protected void	grow(int cbCap) Grow the underlying byte array to at least the specified size.
boolean	isByteArrayPrivate() Determine if the underlying byte[] should be treated as private data.
int	length() Determine the length of the data that is in the buffer.
void	makeByteArrayPrivate() Make sure that the underlying byte[] will be treated as private data.
void	retain(int of, int cb) Starting with the byte at offset of, retain cb bytes in this WriteBuffer, such that the byte at offset of is shifted to offset 0, the byte at offset of + 1 is shifted to offset 1, and so on up to the byte at offset of + cb - 1, which is shifted to offset cb - 1.
protected void	updateLength(int cb) Update the length if the passed length is greater than the current buffer length.
void	write(int ofDest, byte b) Store the specified byte at the specified offset within the buffer.
void	write(int ofDest, byte[] abSrc, int ofSrc, int cbSrc) Store the specified number of bytes from the specified location within the passed byte array at the specified offset within this buffer.
void	write(int ofDest, InputStreaming stream, int cbSrc) Store the specified number of bytes from the specified InputStreaming object at the specified offset within this buffer.
void	write(int ofDest, ReadBuffer bufSrc, int ofSrc, int cbSrc) Store the specified portion of the contents of the specified ReadBuffer at the specified offset within this buffer.

Methods inherited from class com.tangosol.io.AbstractWriteBuffer

clear, clone, copyBufferInputPortion, copyBufferInputRemainder, getAppendingBufferOutput, getBufferOutput, getReadBuffer, getWriteBuffer, getWriteBuffer, retain, tmpbuf, tmpbuf, toBinary, toByteArray, write, write, write

Field Detail

m_ab

protected byte[] m_ab

The byte array that holds the binary data.

m_cb

protected int m_cb

Number of bytes in the byte array that have been written by this WriteBuffer. This is the length.

m_cbMax

protected int m_cbMax

Number of bytes that the byte array can be grown to. This is the maximum capacity.

m_bufUnsafe

protected transient ByteArrayReadBuffer m_bufUnsafe

Cached ReadBuffer to quickly provide an answer to getUnsafeReadBuffer().

Constructor Detail

ByteArrayWriteBuffer

protected ByteArrayWriteBuffer()

Default constructor; intended only for use by subclasses.

Note that this default constructor leaves the buffer in an invalid state.

ByteArrayWriteBuffer

public ByteArrayWriteBuffer(byte[] ab)

Construct a ByteArrayWriteBuffer on a byte array.

Parameters:

ab - a byte array

Throws:

java.lang.NullPointerException - if ab is null

ByteArrayWriteBuffer

public ByteArrayWriteBuffer(int cbCap)

Construct an ByteArrayWriteBuffer with a certain initial capacity.

Parameters:

cbCap - initial capacity

Throws:

java.lang.IllegalArgumentException - if cbCap is negative

ByteArrayWriteBuffer

public ByteArrayWriteBuffer(int cbCap,
                            int cbMax)

Construct an ByteArrayWriteBuffer with a certain initial capacity and a certain maximum capacity.

Parameters:

cbCap - initial capacity

cbMax - maximum capacity

Throws:

java.lang.IllegalArgumentException - if cbCap or cbMax is negative, or if cbCap is greater than cbMax

Method Detail

write

public void write(int ofDest,
                  byte b)

Store the specified byte at the specified offset within the buffer.

For purposes of side-effects and potential exceptions, this method is functionally equivalent to the following code:

 byte[] abSrc = new byte[1];
 abSrc[0] = b;
 write(ofDest, abSrc, 0, abSrc.length);
 

Specified by:

write in interface WriteBuffer

Specified by:

write in class AbstractWriteBuffer

Parameters:

ofDest - the offset within this buffer to store the passed data

b - the byte to store in this buffer

write

public void write(int ofDest,
                  byte[] abSrc,
                  int ofSrc,
                  int cbSrc)

Store the specified number of bytes from the specified location within the passed byte array at the specified offset within this buffer.

As a result of this method, the buffer length as reported by the length() method will become Math.max(length(), ofDest + cbSrc).

As a result of this method, the buffer capacity as reported by the getCapacity() method will not change if the new value returned by length() would not exceed the old value returned by getCapacity(); otherwise, the capacity will be increased such that getCapacity() >= length(). Regardless, it is always true that getCapacity() >= length() and getMaximumCapacity() >= getCapacity(). If the buffer capacity cannot be increased due to resource constraints, an undesignated Error or RuntimeException will be thrown, such as OutOfMemoryError.

Specified by:

write in interface WriteBuffer

Specified by:

write in class AbstractWriteBuffer

Parameters:

ofDest - the offset within this buffer to store the passed data

abSrc - the array containing the bytes to store in this buffer

ofSrc - the offset within the passed byte array to copy from

cbSrc - the number of bytes to copy from the passed byte array

Throws:

java.lang.NullPointerException - if abSrc is null

java.lang.IndexOutOfBoundsException - if ofDest, ofSrc or cbSrc is negative, if ofSrc + cbSrc is greater than abSrc.length, or if ofDest + cbSrc is greater than getMaximumCapacity()

write

public void write(int ofDest,
                  ReadBuffer bufSrc,
                  int ofSrc,
                  int cbSrc)

Store the specified portion of the contents of the specified ReadBuffer at the specified offset within this buffer.

For purposes of side-effects and potential exceptions, this method is functionally equivalent to the following code:

 byte[] abSrc = bufSrc.toByteArray(ofSrc, cbSrc);
 write(ofDest, abSrc, 0, abSrc.length);
 

Specified by:

write in interface WriteBuffer

Overrides:

write in class AbstractWriteBuffer

Parameters:

ofDest - the offset within this buffer to store the passed data

bufSrc - the array of bytes to store in this buffer

ofSrc - the offset within the passed ReadBuffer to copy from

cbSrc - the number of bytes to copy from the passed ReadBuffer

write

public void write(int ofDest,
                  InputStreaming stream,
                  int cbSrc)
           throws java.io.IOException

Store the specified number of bytes from the specified InputStreaming object at the specified offset within this buffer.

For purposes of side-effects and potential exceptions, this method is functionally similar to the following code:

 DataInputStream streamData = new DataInputStream(
         new WrapperInputStream(stream));
 byte[] abSrc = new byte[cbSrc];
 streamData.readFully(abSrc);
 write(ofDest, abSrc, 0, abSrc.length);
 

Specified by:

write in interface WriteBuffer

Overrides:

write in class AbstractWriteBuffer

Parameters:

ofDest - the offset within this buffer to store the passed data

stream - the stream of bytes to read and store in this buffer

cbSrc - the exact number of bytes to read from the stream and put in this buffer

Throws:

java.io.IOException - if an IOException occurs reading from the passed stream

length

public int length()

Determine the length of the data that is in the buffer. This is the actual number of bytes of data that have been written to the buffer, not the capacity of the buffer.

Specified by:

length in interface WriteBuffer

Specified by:

length in class AbstractWriteBuffer

Returns:

the number of bytes of data represented by this WriteBuffer

retain

public void retain(int of,
                   int cb)

Starting with the byte at offset of, retain cb bytes in this WriteBuffer, such that the byte at offset of is shifted to offset 0, the byte at offset of + 1 is shifted to offset 1, and so on up to the byte at offset of + cb - 1, which is shifted to offset cb - 1. After this method, the length of the buffer as indicated by the length() method will be equal to cb.

Legal values for the offset of the first byte to retain of are (of >= 0 && of <= length()). Legal values for the number of bytes to retain cb are (cb >= 0 && cb <= length()), such that (of + cb <= length()).

If cb is zero, then this method will have the same effect as clear. If of is zero, then this method will have the effect of truncating the data in the buffer, but no bytes will be shifted within the buffer.

The effect on the capacity of the buffer is implementation-specific; some implementations are expected to retain the same capacity while others are expected to shrink accordingly.

Specified by:

retain in interface WriteBuffer

Specified by:

retain in class AbstractWriteBuffer

Parameters:

of - the offset of the first byte within the WriteBuffer that will be retained

cb - the number of bytes to retain

Throws:

java.lang.IndexOutOfBoundsException - if of or cb is negative of if of + cb is greater than length()

getCapacity

public int getCapacity()

Determine the number of bytes that the buffer can hold without resizing itself. In other words, a WriteBuffer has getCapacity() - length() bytes that can be written to it without overflowing the current underlying buffer allocation. Since the buffer is an abstract concept, the actual mechanism for the underlying buffer is not known, but it could be a Java NIO buffer, or a byte array, etc.

Note that if the maximum size returned by getMaximumCapacity() is greater than the current size returned by this method, then the WriteBuffer will automatically resize itself to allocate more space when the amount of data written to it passes the current size.

Specified by:

getCapacity in interface WriteBuffer

Specified by:

getCapacity in class AbstractWriteBuffer

Returns:

the number of bytes of data that this WriteBuffer can hold without resizing its underlying buffer

getMaximumCapacity

public int getMaximumCapacity()

Determine the maximum number of bytes that the buffer can hold. If the maximum size is greater than the current size, then the buffer is expected to resize itself as necessary up to the maximum size in order to contain the data given to it.

Specified by:

getMaximumCapacity in interface WriteBuffer

Overrides:

getMaximumCapacity in class AbstractWriteBuffer

Returns:

the maximum number of bytes of data that the WriteBuffer can hold

getBufferOutput

public WriteBuffer.BufferOutput getBufferOutput(int of)

Get a BufferOutput object to write data to this buffer starting at a particular offset.

Note that each call to this method will return a new BufferOutput object, with the possible exception being that a zero-length non-resizing WriteBuffer could always return the same instance (since it is not writable).

This is functionally equivalent to:

 BufferOutput bufout = getBufferOutput();
 bufout.setOffset(of);
 return bufout;
 

Specified by:

getBufferOutput in interface WriteBuffer

Overrides:

getBufferOutput in class AbstractWriteBuffer

Parameters:

of - the offset of the first byte of this buffer that the BufferOutput will write to

Returns:

a BufferOutput that will write to this buffer

Throws:

java.lang.IndexOutOfBoundsException - if of is negative, or of is larger than the getMaximumCapacity() of this WriteBuffer object

getUnsafeReadBuffer

public ReadBuffer getUnsafeReadBuffer()

Get a ReadBuffer object to read data from this buffer. This method is not guaranteed to return a snapshot of this buffer's data, nor is it guaranteed to return a live view of this buffer, which means that subsequent changes to this WriteBuffer may or may not affect the contents and / or the length of the returned ReadBuffer.

To get a snapshot, use the AbstractWriteBuffer.getReadBuffer() method.

Specified by:

getUnsafeReadBuffer in interface WriteBuffer

Specified by:

getUnsafeReadBuffer in class AbstractWriteBuffer

Returns:

a ReadBuffer that reflects the contents of this WriteBuffer but whose behavior is undefined if the WriteBuffer is modified

isByteArrayPrivate

public boolean isByteArrayPrivate()

Determine if the underlying byte[] should be treated as private data.

Returns:

true iff the underlying data should not ever be exposed by this object

makeByteArrayPrivate

public void makeByteArrayPrivate()

Make sure that the underlying byte[] will be treated as private data.

getRawByteArray

public byte[] getRawByteArray()

Obtain the byte array that this WriteBuffer uses. If the underlying byte array is private, then this method will always return a copy of the portion of the byte array that this WriteBuffer represents as if the called had called AbstractWriteBuffer.toByteArray().

Returns:

the byte array that this WriteBuffer uses

copyStream

protected int copyStream(int ofDest,
                         InputStreaming stream,
                         int cbMax)
                  throws java.io.IOException

Store the remaining contents of the specified InputStreaming object at the specified offset within this buffer.

Overrides:

copyStream in class AbstractWriteBuffer

Parameters:

ofDest - the offset within this buffer to store the passed data

stream - the stream of bytes to read and store in this buffer

cbMax - the maximum number of bytes to copy

Returns:

the actual number of bytes read from the InputStreaming object and written to this buffer

Throws:

java.io.IOException - if an IOException occurs reading from the passed stream or if the limit is reached without emptying the source stream

checkBounds

protected void checkBounds(int of,
                           int cb)

Validate the ranges for the passed bounds and make sure that the underlying array is big enough to handle them.

Parameters:

of - the offset that data is about to be written to

cb - the length of the data that is about to be written

grow

protected void grow(int cbCap)

Grow the underlying byte array to at least the specified size.

Parameters:

cbCap - the required or requested capacity

updateLength

protected void updateLength(int cb)

Update the length if the passed length is greater than the current buffer length.

Parameters:

cb - the count of the last byte written (or the index of the next byte to write)

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