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Oracle® Coherence Java API Reference
v3.5.1

E15583-01


com.tangosol.io.nio
Class ByteBufferWriteBuffer

java.lang.Object
  extended by com.tangosol.io.AbstractWriteBuffer
      extended by com.tangosol.io.nio.ByteBufferWriteBuffer

All Implemented Interfaces:
WriteBuffer

public class ByteBufferWriteBuffer
extends AbstractWriteBuffer
implements WriteBuffer

A WriteBuffer implementation on top of a Java NIO ByteBuffer.

Author:
cp 2006.04.05

Nested Class Summary
 class ByteBufferWriteBuffer.ByteBufferOutput
          This is a simple implementation of the BufferOutput interface on top of a ByteBuffer.

 

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

 

Fields inherited from class com.tangosol.io.AbstractWriteBuffer
CHAR_BUF_MASK, CHAR_BUF_SIZE, m_achBuf, NO_BINARY, NO_BYTES

 

Constructor Summary
ByteBufferWriteBuffer(java.nio.ByteBuffer buf)
          Construct a ByteBufferWriteBuffer on an NIO ByteBuffer.

 

Method Summary
 java.lang.Object clone()
          Create a clone of this WriteBuffer object.
 WriteBuffer.BufferOutput getBufferOutput(int of)
          Get a BufferOutput object to write data to this buffer starting at a particular offset.
 java.nio.ByteBuffer getByteBuffer()
          Obtain the ByteBuffer that this WriteBuffer is based on.
 int getCapacity()
          Determine the number of bytes that the buffer can hold without resizing itself.
 ReadBuffer getReadBuffer()
          Get a ReadBuffer object that is a snapshot of this WriteBuffer's data.
 ReadBuffer getUnsafeReadBuffer()
          Get a ReadBuffer object to read data from this buffer.
 int length()
          Determine the length of the data that is in the buffer.
 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.
 Binary toBinary()
          Returns a new Binary object that holds the complete contents of this WriteBuffer.
 byte[] toByteArray()
          Returns a new byte array that holds the complete contents of this WriteBuffer.
 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, 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, copyBufferInputPortion, copyBufferInputRemainder, copyStream, getAppendingBufferOutput, getBufferOutput, getMaximumCapacity, getWriteBuffer, getWriteBuffer, retain, tmpbuf, tmpbuf, write, write, write, write

 

Methods inherited from interface com.tangosol.io.WriteBuffer
clear, getAppendingBufferOutput, getBufferOutput, getMaximumCapacity, getWriteBuffer, getWriteBuffer, retain, write, write, write, write

 

Constructor Detail

ByteBufferWriteBuffer

public ByteBufferWriteBuffer(java.nio.ByteBuffer buf)
Construct a ByteBufferWriteBuffer on an NIO ByteBuffer.
Parameters:
buf - the underlying NIO ByteBuffer

Method Detail

getByteBuffer

public java.nio.ByteBuffer getByteBuffer()
Obtain the ByteBuffer that this WriteBuffer is based on.
Returns:
the underlying ByteBuffer

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 AbstractWriteBuffer.length() method will become Math.max(AbstractWriteBuffer.length(), ofDest + cbSrc).

As a result of this method, the buffer capacity as reported by the AbstractWriteBuffer.getCapacity() method will not change if the new value returned by AbstractWriteBuffer.length() would not exceed the old value returned by AbstractWriteBuffer.getCapacity(); otherwise, the capacity will be increased such that AbstractWriteBuffer.getCapacity() >= AbstractWriteBuffer.length(). Regardless, it is always true that AbstractWriteBuffer.getCapacity() >= AbstractWriteBuffer.length() and AbstractWriteBuffer.getMaximumCapacity() >= AbstractWriteBuffer.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

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

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 AbstractWriteBuffer.length() method will be equal to cb.

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

getCapacity

public int getCapacity()
Determine the number of bytes that the buffer can hold without resizing itself. In other words, a WriteBuffer has getCapacity() - AbstractWriteBuffer.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 AbstractWriteBuffer.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

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

getReadBuffer

public ReadBuffer getReadBuffer()
Get a ReadBuffer object that is a snapshot of this WriteBuffer's data.

This method is functionally equivalent to the following code:


 ReadBuffer buf = getUnsafeReadBuffer();
 byte[] ab = buf.toByteArray();
 return new ByteArrayReadBuffer(ab);
 
Specified by:
getReadBuffer in interface WriteBuffer
Overrides:
getReadBuffer in class AbstractWriteBuffer
Returns:
a ReadBuffer that reflects the point-in-time contents of this WriteBuffer

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

toByteArray

public byte[] toByteArray()
Returns a new byte array that holds the complete contents of this WriteBuffer.

This method is functionally equivalent to the following code:


 return getUnsafeReadBuffer().toByteArray();
 
Specified by:
toByteArray in interface WriteBuffer
Overrides:
toByteArray in class AbstractWriteBuffer
Returns:
the contents of this WriteBuffer as a byte[]

toBinary

public Binary toBinary()
Returns a new Binary object that holds the complete contents of this WriteBuffer.

This method is functionally equivalent to the following code:


 return getUnsafeReadBuffer().toBinary();
 
Specified by:
toBinary in interface WriteBuffer
Overrides:
toBinary in class AbstractWriteBuffer
Returns:
the contents of this WriteBuffer as a Binary object

clone

public java.lang.Object clone()
Create a clone of this WriteBuffer object. Changes to the clone will not affect the original, and vice-versa.
Specified by:
clone in interface WriteBuffer
Overrides:
clone in class AbstractWriteBuffer
Returns:
a WriteBuffer object with the same contents as this WriteBuffer object

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Oracle® Coherence Java API Reference
v3.5.1

E15583-01


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