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edu.emory.mathcs.util.io
Class BufferedPipe
java.lang.Objectedu.emory.mathcs.util.io.BufferedPipe
- public class BufferedPipe
- extends java.lang.Object
In-memory pipe that enables buffered sequential data transfer between threads. Pipe has two ends: source and sink. Source is an output stream into which the writer writes bytes. Sink is the input stream from which reader reads bytes. Data that was wrote to the source but not yet read from the sink are kept in a pipe buffer.
This implementation features dynamic buffer sizing, so that memory consumption is minimized if there is little data to buffer. Buffer is upsized if more space is needed and downsized when data is read. Resizing never causes data copying.
This implementation supports concurrent reads and writes.
Memory usage limits and allocation policy can be controlled via provided edu.emory.mathcs.util.allocator.Allocator. For example, multiple pipes can share allocator with fixed maximum memory footprint, thus limiting total memory used for I/O buffering.
- Version:
- 1.0
| Nested Class Summary | |
(package private) static class |
BufferedPipe.Chunk
|
private class |
BufferedPipe.PipeRedirectibleInputStream
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| Field Summary | |
(package private) edu.emory.mathcs.util.allocator.Allocator |
allocator
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(package private) BufferedPipe.Chunk |
begChunk
|
(package private) int |
chunksize
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private static int |
DATA
|
(package private) static edu.emory.mathcs.util.allocator.Allocator |
defaultAllocator
Default allocator with maximum memory footprint of 10 MB. |
(package private) java.lang.Object |
emptyLock
|
(package private) BufferedPipe.Chunk |
endChunk
|
private static int |
EOF
|
(package private) java.lang.Object |
fullLock
|
protected java.io.InputStream |
sink
Sink of the pipe. |
(package private) boolean |
sinkClosed
|
protected java.io.OutputStream |
source
Source of the pipe. |
(package private) boolean |
sourceClosed
|
private static int |
TIMEOUT
|
(package private) java.lang.Thread |
writerThread
|
| Constructor Summary | |
BufferedPipe()
Creates a new pipe with a default shared allocator with 10 MB footprint limit, and a default initial chunk size of 8 KB. |
|
BufferedPipe(edu.emory.mathcs.util.allocator.Allocator allocator)
Creates a new pipe with specified allocator and a default initial chunk size of 8 KB. |
|
BufferedPipe(edu.emory.mathcs.util.allocator.Allocator allocator,
int chunksize)
Creates a new pipe with specified allocator and initial chunk size. |
|
BufferedPipe(int chunksize)
Creates a new pipe with a default shared allocator with 10 MB footprint limit, and with specified initial chunk size. |
|
| Method Summary | |
private void |
checkWriteConsistency()
|
(package private) void |
closeSink()
|
(package private) void |
closeSource()
|
private int |
ensureData(long timeout)
Waits until there is at least one byte available for reading in current chunk |
private void |
ensureSpace()
Called only by write() operations |
private void |
fireIOStateChanged()
|
private boolean |
isEmpty()
Used only by read() operations. |
long |
length()
Returns the current length of the pipe, i.e. |
private static java.io.InterruptedIOException |
newInterruptedIOException(java.lang.InterruptedException e)
|
(package private) int |
read(byte[] buf,
int off,
int len,
long timeout)
|
(package private) int |
read(long timeout)
|
(package private) int |
read(java.io.OutputStream os,
int len,
long timeout)
|
java.io.InputStream |
sink()
Returns the sink of this pipe, from where reader can read data. |
java.io.OutputStream |
source()
Returns the source of this pipe, where writer can write data. |
(package private) void |
write(byte[] buf,
int off,
int len)
|
(package private) void |
write(int v)
|
| Methods inherited from class java.lang.Object |
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait |
| Field Detail |
defaultAllocator
static edu.emory.mathcs.util.allocator.Allocator defaultAllocator
- Default allocator with maximum memory footprint of 10 MB.
allocator
final edu.emory.mathcs.util.allocator.Allocator allocator
begChunk
volatile BufferedPipe.Chunk begChunk
endChunk
volatile BufferedPipe.Chunk endChunk
sourceClosed
volatile boolean sourceClosed
sinkClosed
volatile boolean sinkClosed
chunksize
volatile int chunksize
emptyLock
final java.lang.Object emptyLock
fullLock
final java.lang.Object fullLock
source
protected final java.io.OutputStream source
- Source of the pipe.
sink
protected final java.io.InputStream sink
- Sink of the pipe.
writerThread
volatile java.lang.Thread writerThread
DATA
private static final int DATA
- See Also:
- Constant Field Values
EOF
private static final int EOF
- See Also:
- Constant Field Values
TIMEOUT
private static final int TIMEOUT
- See Also:
- Constant Field Values
| Constructor Detail |
BufferedPipe
public BufferedPipe()
- Creates a new pipe with a default shared allocator with 10 MB footprint
limit, and a default initial chunk size of 8 KB.
BufferedPipe
public BufferedPipe(int chunksize)
- Creates a new pipe with a default shared allocator with 10 MB footprint
limit, and with specified initial chunk size. Specifying large
initial chunk size increases initial memory footprint, but may slightly
improve initial performance of bulk data transfer.
BufferedPipe
public BufferedPipe(edu.emory.mathcs.util.allocator.Allocator allocator)
- Creates a new pipe with specified allocator and a default initial chunk
size of 8 KB.
The allocator is used to provide memory buffers used by the pipe.
BufferedPipe
public BufferedPipe(edu.emory.mathcs.util.allocator.Allocator allocator, int chunksize)
- Creates a new pipe with specified allocator and initial chunk size.
The allocator is used to provide memory buffers used by the pipe.
Specifying large initial chunk size increases initial memory footprint,
but may slightly improve performance for bulk data transfer.
| Method Detail |
source
public java.io.OutputStream source()
- Returns the source of this pipe, where writer can write data.
sink
public java.io.InputStream sink()
- Returns the sink of this pipe, from where reader can read data.
length
public long length()
- Returns the current length of the pipe, i.e. the number of bytes
buffered and available for read. This is a snapshot value only.
read
int read(long timeout) throws java.io.IOException, edu.emory.mathcs.util.concurrent.TimeoutException
read
int read(byte[] buf,
int off,
int len,
long timeout)
throws java.io.IOException,
edu.emory.mathcs.util.concurrent.TimeoutException
read
int read(java.io.OutputStream os, int len, long timeout) throws java.io.IOException, edu.emory.mathcs.util.concurrent.TimeoutException
write
void write(int v)
throws java.io.IOException
write
void write(byte[] buf,
int off,
int len)
throws java.io.IOException
closeSource
void closeSource()
closeSink
void closeSink()
fireIOStateChanged
private void fireIOStateChanged()
isEmpty
private boolean isEmpty()
- Used only by read() operations.
ensureData
private int ensureData(long timeout)
throws java.io.IOException
- Waits until there is at least one byte available for reading
in current chunk
ensureSpace
private void ensureSpace()
throws java.io.IOException
- Called only by write() operations
checkWriteConsistency
private void checkWriteConsistency()
throws java.io.IOException
newInterruptedIOException
private static java.io.InterruptedIOException newInterruptedIOException(java.lang.InterruptedException e)
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