| java.lang.Object
 com.Ostermiller.util.CircularObjectBuffer
| CircularObjectBuffer | | public class CircularObjectBuffer (Code) | | Implements the Circular Buffer producer/consumer model for Objects.
More information about this class is available from ostermiller.org.
This class is thread safe.
See Also: CircularCharBuffer
See Also: CircularByteBuffer
author:
Stephen Ostermiller http://ostermiller.org/contact.pl?regarding=Java+Utilities<
Parameters:
ElementType - > Type of object allowed in this circular buffer
since:
ostermillerutils 1.00.00 |
| Field Summary | |
| final public static int | INFINITE_SIZE
A buffer that will grow as things are added. | | protected boolean | blockingWrite
| | protected ElementType[] | 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 volatile boolean | infinite
| | protected boolean | inputDone
True when no more input is coming into this buffer. | | protected volatile int | readPosition
Index of the first Object available to be read. | | protected volatile int | writePosition
Index of the first Object available to be written. |
| Constructor Summary | |
| public | CircularObjectBuffer()
Create a new buffer with a default capacity. | | public | CircularObjectBuffer(int size)
Create a new buffer with given capacity. | | public | CircularObjectBuffer(boolean blockingWrite)
Create a new buffer with a default capacity and
given blocking behavior. | | public | CircularObjectBuffer(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 void | done()
This method should be used by the producer to signal to the consumer
that the producer is done producing objects and that the consumer
should stop asking for objects once it has used up buffered objects.
Once the producer has signaled that it is done, further write() invocations
will cause an IllegalStateException to be thrown. | | public int | getAvailable()
Get number of Objects that are available to be read. | | public int | getSize()
Get the capacity of this buffer. | | public int | getSpaceLeft()
Get the number of Objects this buffer has free for
writing. | | public ElementType | read()
Get a single Object from this buffer. | | public int | read(ElementType[] buf)
Get Objects into an array from this buffer. | | public int | read(ElementType[] buf, int off, int len)
Get Objects into a portion of an array from this buffer. | | public long | skip(long n)
Skip Objects. | | public void | write(ElementType[] buf)
Fill this buffer with array of Objects. | | public void | write(ElementType[] buf, int off, int len)
Fill this buffer with a portion of an array of Objects.
This method should be called by the producer.
If the buffer allows blocking writes, this method will block until
all the data has been written rather than throw an IOException.
Parameters:
buf - Array of Objects
Parameters:
off - Offset from which to start writing Objects
Parameters:
len - - Number of Objects to write
throws:
BufferOverflowException - if buffer does not allow blocking writesand the buffer is full. | | public void | write(ElementType o)
Add a single Object to this buffer. |
| 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 ElementType[] 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 readPostion and the
writePosition equal to each other. A full buffer will have
the writePosition one less than the readPostion.
There are two important indexes into the buffer:
The readPosition, and the writePosition. The Objects
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 readPosition,
wrapping around the end of the 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 |
| inputDone | | protected boolean inputDone(Code) | | True when no more input is coming into this buffer. At that
point reading from the buffer may return null if the buffer
is empty, otherwise a read will block until an Object is available.
since:
ostermillerutils 1.00.00 |
| readPosition | | protected volatile int readPosition(Code) | | Index of the first Object available to be read.
since:
ostermillerutils 1.00.00 |
| writePosition | | protected volatile int writePosition(Code) | | Index of the first Object available to be written.
since:
ostermillerutils 1.00.00 |
| CircularObjectBuffer | | public CircularObjectBuffer()(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 |
| CircularObjectBuffer | | public CircularObjectBuffer(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 Objects for
special purposes and capacity number of Objects 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 Objects or CircularObjectBuffer.INFINITE_SIZE.
since:
ostermillerutils 1.00.00 |
| CircularObjectBuffer | | public CircularObjectBuffer(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 |
| CircularObjectBuffer | | public CircularObjectBuffer(int size, boolean blockingWrite)(Code) | | Create a new buffer with the given capacity and
blocking behavior.
Note that the buffer may reserve some Objects for
special purposes and capacity number of Objects 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 Objects or CircularObjectBuffer.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 |
| done | | public void done()(Code) | | This method should be used by the producer to signal to the consumer
that the producer is done producing objects and that the consumer
should stop asking for objects once it has used up buffered objects.
Once the producer has signaled that it is done, further write() invocations
will cause an IllegalStateException to be thrown. Calling done() multiple times,
however, has no effect.
since:
ostermillerutils 1.00.00 |
| getAvailable | | public int getAvailable()(Code) | | Get number of Objects that are available to be read.
Note that the number of Objects available plus
the number of Objects free may not add up to the
capacity of this buffer, as the buffer may reserve some
space for other purposes.
the size in Objects of this buffer
since:
ostermillerutils 1.00.00 |
| getSize | | public int getSize()(Code) | | Get the capacity of this buffer.
Note that the number of Objects available plus
the number of Objects free may not add up to the
capacity of this buffer, as the buffer may reserve some
space for other purposes.
the size in Objects of this buffer
since:
ostermillerutils 1.00.00 |
| getSpaceLeft | | public int getSpaceLeft()(Code) | | Get the number of Objects this buffer has free for
writing.
Note that the number of Objects available plus
the number of Objects 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 Objects of this buffer
since:
ostermillerutils 1.00.00 |
| read | | public ElementType read() throws InterruptedException(Code) | | Get a single Object from this buffer. This method should be called
by the consumer.
This method will block until a Object is available or no more
objects are available.
The Object read, or null if there are no more objects
throws:
InterruptedException - if the thread is interrupted while waiting.
since:
ostermillerutils 1.00.00 |
| read | | public int read(ElementType[] buf) throws InterruptedException(Code) | | Get Objects into an array from this buffer. This method should
be called by the consumer.
This method will block until some input is available,
or there is no more input.
Parameters:
buf - Destination buffer. The number of Objects read, or -1 there willbe no more objects available.
throws:
InterruptedException - if the thread is interrupted while waiting.
since:
ostermillerutils 1.00.00 |
| read | | public int read(ElementType[] buf, int off, int len) throws InterruptedException(Code) | | Get Objects into a portion of an array from this buffer. This
method should be called by the consumer.
This method will block until some input is available,
an I/O error occurs, or the end of the stream is reached.
Parameters:
buf - Destination buffer.
Parameters:
off - Offset at which to start storing Objects.
Parameters:
len - Maximum number of Objects to read. The number of Objects read, or -1 there willbe no more objects available.
throws:
InterruptedException - if the thread is interrupted while waiting.
since:
ostermillerutils 1.00.00 |
| skip | | public long skip(long n) throws InterruptedException, IllegalArgumentException(Code) | | Skip Objects. This method should be used by the consumer
when it does not care to examine some number of Objects.
This method will block until some Objects are available,
or there will be no more Objects available.
Parameters:
n - The number of Objects to skip The number of Objects actually skipped
throws:
IllegalArgumentException - if n is negative.
throws:
InterruptedException - if the thread is interrupted while waiting.
since:
ostermillerutils 1.00.00 |
| write | | public void write(ElementType[] buf) throws BufferOverflowException, IllegalStateException, InterruptedException(Code) | | Fill this buffer with array of Objects. This method should be called
by the producer.
If the buffer allows blocking writes, this method will block until
all the data has been written rather than throw a BufferOverflowException.
Parameters:
buf - Array of Objects to be written
throws:
BufferOverflowException - if buffer does not allow blocking writesand the buffer is full. If the exception is thrown, no datawill have been written since the buffer was set to be non-blocking.
throws:
IllegalStateException - if done() has been called.
throws:
InterruptedException - if the write is interrupted.
since:
ostermillerutils 1.00.00 |
| write | | public void write(ElementType[] buf, int off, int len) throws BufferOverflowException, IllegalStateException, InterruptedException(Code) | | Fill this buffer with a portion of an array of Objects.
This method should be called by the producer.
If the buffer allows blocking writes, this method will block until
all the data has been written rather than throw an IOException.
Parameters:
buf - Array of Objects
Parameters:
off - Offset from which to start writing Objects
Parameters:
len - - Number of Objects to write
throws:
BufferOverflowException - if buffer does not allow blocking writesand the buffer is full. If the exception is thrown, no datawill have been written since the buffer was set to be non-blocking.
throws:
IllegalStateException - if done() has been called.
throws:
InterruptedException - if the write is interrupted.
since:
ostermillerutils 1.00.00 |
| write | | public void write(ElementType o) throws BufferOverflowException, IllegalStateException, InterruptedException(Code) | | Add a single Object to this buffer. This method should be
called by the producer.
If the buffer allows blocking writes, this method will block until
all the data has been written rather than throw an IOException.
Parameters:
o - Object to be written.
throws:
BufferOverflowException - if buffer does not allow blocking writesand the buffer is full. If the exception is thrown, no datawill have been written since the buffer was set to be non-blocking.
throws:
IllegalStateException - if done() has been called.
throws:
InterruptedException - if the write is interrupted.
since:
ostermillerutils 1.00.00 |
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