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Oracle® Coherence Java API Reference Release 3.6.0.0 E15725-01 |
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java.lang.Object
com.tangosol.io.AbstractWriteBuffer
com.tangosol.io.DelegatingWriteBuffer
public final class DelegatingWriteBuffer
A DelegatingWriteBuffer is a WriteBuffer that writes through to an underlying (or "containing") WriteBuffer. Basically, it allows a process that is writing to a WriteBuffer to ask for a "protected" sub-portion of that WriteBuffer to hand to a second process, such that the second process can not affect (or even read from) the WriteBuffer outside of the portion that the first process explicitly designated as viewable and modifiable.
This implementation is explicitly not thread-safe.
Nested Class Summary | |
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class |
DelegatingWriteBuffer.DelegatingBufferOutput A BufferOutput implementation that delegates to a BufferOutput implementation, except that its offset range is shifted and limited. |
Nested classes/interfaces inherited from class com.tangosol.io.AbstractWriteBuffer |
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AbstractWriteBuffer.AbstractBufferOutput |
Nested classes/interfaces inherited from interface com.tangosol.io.WriteBuffer |
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WriteBuffer.BufferOutput |
Field Summary | |
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protected WriteBuffer |
m_buf The WriteBuffer to delegate to; the "containing" WriteBuffer. |
protected int |
m_cb Length in bytes of this WriteBuffer. |
protected int |
m_cbMax Maximum number of bytes in this WriteBuffer. |
protected int |
m_ofStart Offset into the containing WriteBuffer where this WriteBuffer starts. |
Fields inherited from class com.tangosol.io.AbstractWriteBuffer |
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CHAR_BUF_MASK, CHAR_BUF_SIZE, m_achBuf, NO_BINARY, NO_BYTES |
Constructor Summary | |
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DelegatingWriteBuffer(WriteBuffer buf, int of, int cb) Construct a DelegatingWriteBuffer that will delegate to the containing WriteBuffer. |
Method Summary | |
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protected void |
checkBounds(int of, int cb) Test an offset and length of data to write to see if it can be written to this buffer. |
void |
clear() Set the length of the buffer as indicated by the WriteBuffer.length() method to zero.
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. |
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. 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:
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int |
getCapacity() Determine the number of bytes that the buffer can hold without resizing itself. In other words, a WriteBuffer has getCapacity() - WriteBuffer.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 |
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. |
ReadBuffer |
getReadBuffer() Get a ReadBuffer object that is a snapshot of this WriteBuffer's data. This method is functionally equivalent to the following code:
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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 |
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. |
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 WriteBuffer.length() method will be equal to cb.
Legal values for the offset of the first byte to retain of are (of >= 0 && of <= 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. |
Binary |
toBinary() Returns a new Binary object that holds the complete contents of this WriteBuffer. This method is functionally equivalent to the following code:
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byte[] |
toByteArray() Returns a new byte array that holds the complete contents of this WriteBuffer. This method is functionally equivalent to the following code:
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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. For purposes of side-effects and potential exceptions, this method is functionally equivalent to the following code:
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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 As a result of this method, the buffer capacity as reported by the |
void |
write(int ofDest, InputStreaming stream) Store the remaining contents of 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:
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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. For purposes of side-effects and potential exceptions, this method is functionally similar to the following code:
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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:
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Methods inherited from class com.tangosol.io.AbstractWriteBuffer |
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clone, copyBufferInputPortion, copyBufferInputRemainder, getAppendingBufferOutput, getBufferOutput, getWriteBuffer, getWriteBuffer, releaseBuffers, retain, tmpbuf, tmpbuf, write, write |
Field Detail |
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protected WriteBuffer m_buf
protected int m_ofStart
protected int m_cb
protected int m_cbMax
Constructor Detail |
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public DelegatingWriteBuffer(WriteBuffer buf, int of, int cb)
buf
- the containing WriteBufferof
- the offset within the containing WriteBuffer that this WriteBuffer is starting atcb
- the maximum capacity for this WriteBufferMethod Detail |
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public void write(int ofDest, byte b)
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);
write
in interface WriteBuffer
write
in class AbstractWriteBuffer
ofDest
- the offset within this buffer to store the passed datab
- the byte to store in this bufferpublic void write(int ofDest, byte[] abSrc, int ofSrc, int cbSrc)
As a result of this method, the buffer length as reported by the WriteBuffer.length()
method will become Math.max(WriteBuffer.length()
, ofDest + cbSrc).
As a result of this method, the buffer capacity as reported by the WriteBuffer.getCapacity()
method will not change if the new value returned by WriteBuffer.length()
would not exceed the old value returned by WriteBuffer.getCapacity()
; otherwise, the capacity will be increased such that WriteBuffer.getCapacity()
>= WriteBuffer.length()
. Regardless, it is always true that WriteBuffer.getCapacity()
>= WriteBuffer.length()
and WriteBuffer.getMaximumCapacity()
>= WriteBuffer.getCapacity()
. If the buffer capacity cannot be increased due to resource constraints, an undesignated Error or RuntimeException will be thrown, such as OutOfMemoryError.
write
in interface WriteBuffer
write
in class AbstractWriteBuffer
ofDest
- the offset within this buffer to store the passed dataabSrc
- the array containing the bytes to store in this bufferofSrc
- the offset within the passed byte array to copy fromcbSrc
- the number of bytes to copy from the passed byte arraypublic void write(int ofDest, ReadBuffer bufSrc, int ofSrc, int cbSrc)
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);
write
in interface WriteBuffer
write
in class AbstractWriteBuffer
ofDest
- the offset within this buffer to store the passed databufSrc
- the array of bytes to store in this bufferofSrc
- the offset within the passed ReadBuffer to copy fromcbSrc
- the number of bytes to copy from the passed ReadBufferpublic void write(int ofDest, InputStreaming stream) throws IOException
For purposes of side-effects and potential exceptions, this method is functionally similar to the following code:
ByteArrayOutputStream streamOut = new ByteArrayOutputStream();
int b;
while ((b = stream.read()) >= 0)
{
streamOut.write(b);
}
byte[] abSrc = streamOut.toByteArray();
write(ofDest, abSrc, 0, abSrc.length);
write
in interface WriteBuffer
write
in class AbstractWriteBuffer
ofDest
- the offset within this buffer to store the passed datastream
- the stream of bytes to read and store in this bufferIOException
- if an IOException occurs reading from the passed streampublic void write(int ofDest, InputStreaming stream, int cbSrc) throws IOException
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);
write
in interface WriteBuffer
write
in class AbstractWriteBuffer
ofDest
- the offset within this buffer to store the passed datastream
- the stream of bytes to read and store in this buffercbSrc
- the exact number of bytes to read from the stream and put in this bufferIOException
- if an IOException occurs reading from the passed streampublic int length()
length
in interface WriteBuffer
length
in class AbstractWriteBuffer
public void retain(int of, int cb)
WriteBuffer.length()
method will be equal to cb.
Legal values for the offset of the first byte to retain of are (of >= 0 && of <= WriteBuffer.length()
). Legal values for the number of bytes to retain cb are (cb >= 0 && cb <= WriteBuffer.length()
), such that (of + cb <= WriteBuffer.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.
retain
in interface WriteBuffer
retain
in class AbstractWriteBuffer
of
- the offset of the first byte within the WriteBuffer that will be retainedcb
- the number of bytes to retainpublic void clear()
WriteBuffer.length()
method to zero.
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.
clear
in interface WriteBuffer
clear
in class AbstractWriteBuffer
public int getCapacity()
WriteBuffer.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 WriteBuffer.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.
getCapacity
in interface WriteBuffer
getCapacity
in class AbstractWriteBuffer
public int getMaximumCapacity()
getMaximumCapacity
in interface WriteBuffer
getMaximumCapacity
in class AbstractWriteBuffer
public WriteBuffer.BufferOutput getBufferOutput(int of)
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;
getBufferOutput
in interface WriteBuffer
getBufferOutput
in class AbstractWriteBuffer
of
- the offset of the first byte of this buffer that the BufferOutput will write topublic ReadBuffer getReadBuffer()
This method is functionally equivalent to the following code:
ReadBuffer buf = getUnsafeReadBuffer();
byte[] ab = buf.toByteArray();
return new ByteArrayReadBuffer(ab);
getReadBuffer
in interface WriteBuffer
getReadBuffer
in class AbstractWriteBuffer
public ReadBuffer getUnsafeReadBuffer()
To get a snapshot, use the WriteBuffer.getReadBuffer()
method.
getUnsafeReadBuffer
in interface WriteBuffer
getUnsafeReadBuffer
in class AbstractWriteBuffer
public byte[] toByteArray()
This method is functionally equivalent to the following code:
return getUnsafeReadBuffer().toByteArray();
toByteArray
in interface WriteBuffer
toByteArray
in class AbstractWriteBuffer
public Binary toBinary()
This method is functionally equivalent to the following code:
return getUnsafeReadBuffer().toBinary();
toBinary
in interface WriteBuffer
toBinary
in class AbstractWriteBuffer
protected void checkBounds(int of, int cb)
of
- offset to write data atcb
- length in bytes of dataprotected void updateLength(int cb)
cb
- the possible new lengthprotected int copyStream(int ofDest, InputStreaming stream, int cbMax) throws IOException
copyStream
in class AbstractWriteBuffer
ofDest
- the offset within this buffer to store the passed datastream
- the stream of bytes to read and store in this buffercbMax
- the maximum number of bytes to copyIOException
- if an IOException occurs reading from the passed stream or if the limit is reached without emptying the source stream
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Oracle® Coherence Java API Reference Release 3.6.0.0 E15725-01 |
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PREV CLASS NEXT CLASS | FRAMES NO FRAMES | |||||||
SUMMARY: NESTED | FIELD | CONSTR | METHOD | DETAIL: FIELD | CONSTR | METHOD |