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| java.lang.Object
 com.Ostermiller.util.CircularByteBuffer
| CircularByteBuffer | | public class CircularByteBuffer (Code) | | Implements the Circular Buffer producer/consumer model for bytes.
More information about this class is available from ostermiller.org.
Using this class is a simpler alternative to using a PipedInputStream
and a PipedOutputStream. PipedInputStreams and PipedOutputStreams don't support the
mark operation, don't allow you to control buffer sizes that they use,
and have a more complicated API that requires instantiating two
classes and connecting them.
This class is thread safe.
See Also: CircularCharBuffer
See Also: CircularObjectBuffer
author:
Stephen Ostermiller http://ostermiller.org/contact.pl?regarding=Java+Utilities
since:
ostermillerutils 1.00.00 |
| Inner Class :protected class CircularByteBufferInputStream extends InputStream | |
| Inner Class :protected class CircularByteBufferOutputStream extends OutputStream | |
| Field Summary | |
| final public static int | INFINITE_SIZE
A buffer that will grow as things are added. | | protected boolean | blockingWrite
| | protected byte[] | buffer
The circular buffer.
The actual capacity of the buffer is one less than the actual length
of the buffer so that an empty and a full buffer can be
distinguished. | | protected InputStream | in
The InputStream that can empty this buffer. | | protected volatile boolean | infinite
| | protected boolean | inputStreamClosed
| | protected volatile int | markPosition
Index of the first saved byte. | | protected volatile int | markSize
Number of bytes that have to be saved
to support mark() and reset() on the InputStream. | | protected OutputStream | out
The OutputStream that can fill this buffer. | | protected boolean | outputStreamClosed
| | protected volatile int | readPosition
Index of the first byte available to be read. | | protected volatile int | writePosition
Index of the first byte available to be written. |
| Constructor Summary | |
| public | CircularByteBuffer()
Create a new buffer with a default capacity. | | public | CircularByteBuffer(int size)
Create a new buffer with given capacity. | | public | CircularByteBuffer(boolean blockingWrite)
Create a new buffer with a default capacity and
given blocking behavior. | | public | CircularByteBuffer(int size, boolean blockingWrite)
Create a new buffer with the given capacity and
blocking behavior. |
| Method Summary | |
| public void | clear()
Make this buffer ready for reuse. | | public int | getAvailable()
Get number of bytes that are available to be read. | | public InputStream | getInputStream()
Retrieve a InputStream that can be used to empty
this buffer. | | public OutputStream | getOutputStream()
Retrieve a OutputStream that can be used to fill
this buffer.
Write methods may throw a BufferOverflowException if
the buffer is not large enough. | | public int | getSize()
Get the capacity of this buffer. | | public int | getSpaceLeft()
Get the number of bytes this buffer has free for
writing. |
| INFINITE_SIZE | | final public static int INFINITE_SIZE(Code) | | A buffer that will grow as things are added.
since:
ostermillerutils 1.00.00 |
| blockingWrite | | protected boolean blockingWrite(Code) | | True if a write to a full buffer should block until the buffer
has room, false if the write method should throw an IOException
since:
ostermillerutils 1.00.00 |
| buffer | | protected byte[] buffer(Code) | | The circular buffer.
The actual capacity of the buffer is one less than the actual length
of the buffer so that an empty and a full buffer can be
distinguished. An empty buffer will have the markPostion and the
writePosition equal to each other. A full buffer will have
the writePosition one less than the markPostion.
There are three important indexes into the buffer:
The readPosition, the writePosition, and the markPosition.
If the InputStream has never been marked, the readPosition and
the markPosition should always be the same. The bytes
available to be read go from the readPosition to the writePosition,
wrapping around the end of the buffer. The space available for writing
goes from the write position to one less than the markPosition,
wrapping around the end of the buffer. The bytes that have
been saved to support a reset() of the InputStream go from markPosition
to readPosition, wrapping around the end of the buffer.
since:
ostermillerutils 1.00.00 |
| in | | protected InputStream in(Code) | | The InputStream that can empty this buffer.
since:
ostermillerutils 1.00.00 |
| infinite | | protected volatile boolean infinite(Code) | | If this buffer is infinite (should resize itself when full)
since:
ostermillerutils 1.00.00 |
| inputStreamClosed | | protected boolean inputStreamClosed(Code) | | true if the close() method has been called on the InputStream
since:
ostermillerutils 1.00.00 |
| markPosition | | protected volatile int markPosition(Code) | | Index of the first saved byte. (To support stream marking.)
since:
ostermillerutils 1.00.00 |
| markSize | | protected volatile int markSize(Code) | | Number of bytes that have to be saved
to support mark() and reset() on the InputStream.
since:
ostermillerutils 1.00.00 |
| out | | protected OutputStream out(Code) | | The OutputStream that can fill this buffer.
since:
ostermillerutils 1.00.00 |
| outputStreamClosed | | protected boolean outputStreamClosed(Code) | | true if the close() method has been called on the OutputStream
since:
ostermillerutils 1.00.00 |
| readPosition | | protected volatile int readPosition(Code) | | Index of the first byte available to be read.
since:
ostermillerutils 1.00.00 |
| writePosition | | protected volatile int writePosition(Code) | | Index of the first byte available to be written.
since:
ostermillerutils 1.00.00 |
| CircularByteBuffer | | public CircularByteBuffer()(Code) | | Create a new buffer with a default capacity.
Writing to a full buffer will block until space
is available rather than throw an exception.
since:
ostermillerutils 1.00.00 |
| CircularByteBuffer | | public CircularByteBuffer(int size)(Code) | | Create a new buffer with given capacity.
Writing to a full buffer will block until space
is available rather than throw an exception.
Note that the buffer may reserve some bytes for
special purposes and capacity number of bytes may
not be able to be written to the buffer.
Note that if the buffer is of INFINITE_SIZE it will
neither block or throw exceptions, but rather grow
without bound.
Parameters:
size - desired capacity of the buffer in bytes or CircularByteBuffer.INFINITE_SIZE.
since:
ostermillerutils 1.00.00 |
| CircularByteBuffer | | public CircularByteBuffer(boolean blockingWrite)(Code) | | Create a new buffer with a default capacity and
given blocking behavior.
Parameters:
blockingWrite - true writing to a full buffer should blockuntil space is available, false if an exception shouldbe thrown instead.
since:
ostermillerutils 1.00.00 |
| CircularByteBuffer | | public CircularByteBuffer(int size, boolean blockingWrite)(Code) | | Create a new buffer with the given capacity and
blocking behavior.
Note that the buffer may reserve some bytes for
special purposes and capacity number of bytes may
not be able to be written to the buffer.
Note that if the buffer is of INFINITE_SIZE it will
neither block or throw exceptions, but rather grow
without bound.
Parameters:
size - desired capacity of the buffer in bytes or CircularByteBuffer.INFINITE_SIZE.
Parameters:
blockingWrite - true writing to a full buffer should blockuntil space is available, false if an exception shouldbe thrown instead.
since:
ostermillerutils 1.00.00 |
| clear | | public void clear()(Code) | | Make this buffer ready for reuse. The contents of the buffer
will be cleared and the streams associated with this buffer
will be reopened if they had been closed.
since:
ostermillerutils 1.00.00 |
| getAvailable | | public int getAvailable()(Code) | | Get number of bytes that are available to be read.
Note that the number of bytes available plus
the number of bytes free may not add up to the
capacity of this buffer, as the buffer may reserve some
space for other purposes.
the size in bytes of this buffer
since:
ostermillerutils 1.00.00 |
| getInputStream | | public InputStream getInputStream()(Code) | | Retrieve a InputStream that can be used to empty
this buffer.
This InputStream supports marks at the expense
of the buffer size.
the consumer for this buffer.
since:
ostermillerutils 1.00.00 |
| getOutputStream | | public OutputStream getOutputStream()(Code) | | Retrieve a OutputStream that can be used to fill
this buffer.
Write methods may throw a BufferOverflowException if
the buffer is not large enough. A large enough buffer
size must be chosen so that this does not happen or
the caller must be prepared to catch the exception and
try again once part of the buffer has been consumed.
the producer for this buffer.
since:
ostermillerutils 1.00.00 |
| getSize | | public int getSize()(Code) | | Get the capacity of this buffer.
Note that the number of bytes available plus
the number of bytes free may not add up to the
capacity of this buffer, as the buffer may reserve some
space for other purposes.
the size in bytes of this buffer
since:
ostermillerutils 1.00.00 |
| getSpaceLeft | | public int getSpaceLeft()(Code) | | Get the number of bytes this buffer has free for
writing.
Note that the number of bytes available plus
the number of bytes free may not add up to the
capacity of this buffer, as the buffer may reserve some
space for other purposes.
the available space in bytes of this buffer
since:
ostermillerutils 1.00.00 |
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