org.xnio.channels

Class PushBackStreamChannel

java.lang.Object

org.xnio.channels.PushBackStreamChannel

All Implemented Interfaces:

Closeable, AutoCloseable, Channel, InterruptibleChannel, ReadableByteChannel, ScatteringByteChannel, CloseableChannel, Configurable, StreamSourceChannel, SuspendableReadChannel, WrappedChannel<StreamSourceChannel>

public final class PushBackStreamChannel
extends Object
implements StreamSourceChannel, WrappedChannel<StreamSourceChannel>

A stream source channel which can have data pushed back into it. Note that waiting readers will NOT be interrupted when data is pushed back; therefore data should only be pushed back at points when no waiters are expected to exist.

Author:

David M. Lloyd

Field Summary

Fields inherited from interface org.xnio.channels.Configurable

EMPTY

Constructor Summary

Constructors

Constructor and Description
PushBackStreamChannel(StreamSourceChannel channel) Construct a new instance.

Method Summary

Modifier and Type	Method and Description
void	awaitReadable() Block until this channel becomes readable again.
void	awaitReadable(long time, TimeUnit timeUnit) Block until this channel becomes readable again, or until the timeout expires.
void	close() Close this channel.
StreamSourceChannel	getChannel() Get the channel which is wrapped by this object.
ChannelListener.Setter<? extends PushBackStreamChannel>	getCloseSetter() Get the setter which can be used to change the close listener for this channel.
XnioIoThread	getIoThread() Get the I/O thread associated with this channel.
<T> T	getOption(Option<T> option) Get the value of a channel option.
ChannelListener.Setter<? extends PushBackStreamChannel>	getReadSetter() Get the setter which can be used to change the read listener for this channel.
XnioExecutor	getReadThread() Deprecated.
XnioWorker	getWorker() Get the worker for this channel.
boolean	isOpen()
boolean	isReadResumed() Determine whether reads are resumed.
int	read(ByteBuffer dst)
long	read(ByteBuffer[] dsts)
long	read(ByteBuffer[] dsts, int offset, int length)
void	resumeReads() Resume reads on this channel.
void	setCloseListener(ChannelListener<? super PushBackStreamChannel> closeListener)
<T> T	setOption(Option<T> option, T value) Set an option for this channel.
void	setReadListener(ChannelListener<? super PushBackStreamChannel> readListener)
void	shutdownReads() Places this readable channel at "end of stream".
boolean	supportsOption(Option<?> option) Determine whether an option is supported on this channel.
void	suspendReads() Suspend further read notifications on this channel.
long	transferTo(long count, ByteBuffer throughBuffer, StreamSinkChannel target) Transfers bytes into the given channel target.
long	transferTo(long position, long count, FileChannel target) Transfers bytes into the given file from this channel.
void	unget(Pooled<ByteBuffer> buffer) Re-queue the given pooled buffer into this channel.
void	wakeupReads() Resume reads on this channel, and force the read listener to be triggered even if the channel isn't actually readable.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

PushBackStreamChannel

public PushBackStreamChannel(StreamSourceChannel channel)

Construct a new instance.

Parameters:

channel - the channel to wrap

Method Detail

setReadListener

public void setReadListener(ChannelListener<? super PushBackStreamChannel> readListener)

setCloseListener

public void setCloseListener(ChannelListener<? super PushBackStreamChannel> closeListener)

getReadSetter

public ChannelListener.Setter<? extends PushBackStreamChannel> getReadSetter()

Description copied from interface: StreamSourceChannel

Get the setter which can be used to change the read listener for this channel.

Specified by:

getReadSetter in interface StreamSourceChannel

Specified by:

getReadSetter in interface SuspendableReadChannel

Returns:

the setter

getCloseSetter

public ChannelListener.Setter<? extends PushBackStreamChannel> getCloseSetter()

Description copied from interface: StreamSourceChannel

Get the setter which can be used to change the close listener for this channel. If the channel is already closed, then the listener will not be called.

Specified by:

getCloseSetter in interface CloseableChannel

Specified by:

getCloseSetter in interface StreamSourceChannel

Specified by:

getCloseSetter in interface SuspendableReadChannel

Returns:

the setter

transferTo

public long transferTo(long position,
                       long count,
                       FileChannel target)
                throws IOException

Description copied from interface: StreamSourceChannel

Transfers bytes into the given file from this channel. Using this method in preference to FileChannel.transferFrom(ReadableByteChannel, long, long) may provide a performance advantage on some platforms.

If the current thread is interrupted when this method is called, it may throw a InterruptedIOException; however, if this exception is thrown, the InterruptedIOException.bytesTransferred field is guaranteed to be 0.

Specified by:

transferTo in interface StreamSourceChannel

Parameters:

position - the position within the file from which the transfer is to begin

count - the number of bytes to be transferred

target - the file to write to

Returns:

the number of bytes (possibly 0) that were actually transferred

Throws:

IOException - if an I/O error occurs

transferTo

public long transferTo(long count,
                       ByteBuffer throughBuffer,
                       StreamSinkChannel target)
                throws IOException

Description copied from interface: StreamSourceChannel

Transfers bytes into the given channel target. On some platforms, this may avoid copying bytes between user and kernel space. On other platforms, bytes are passed through the throughBuffer parameter's buffer space. On entry, throughBuffer will be cleared. On exit, the buffer will be flipped for emptying, and may possibly be empty or may contain data. If this method returns a value less than count, then the remaining data in throughBuffer may contain data read from this channel which must be written to target to complete the operation. Note that using a direct buffer may provide an intermediate performance gain on platforms without zero-copy facilities.

If the current thread is interrupted when this method is called, it may throw a InterruptedIOException; however, if this exception is thrown, the InterruptedIOException.bytesTransferred field is guaranteed to be 0. Note that the return value is the amount of data that was actually transferred to the StreamSinkChannel. The actual amount of data read could be larger than this, and can be calculated by adding the return value and the amount of data left in throughBuffer.

Specified by:

transferTo in interface StreamSourceChannel

Parameters:

count - the number of bytes to be transferred

throughBuffer - the buffer to copy through.

target - the destination to write to

Returns:

the number of bytes (possibly 0) that were actually transferred, or -1 if the end of input was reached

Throws:

IOException - if an I/O error occurs

read

public int read(ByteBuffer dst)
         throws IOException

Specified by:

read in interface ReadableByteChannel

Throws:

IOException

read

public long read(ByteBuffer[] dsts)
          throws IOException

Specified by:

read in interface ScatteringByteChannel

Throws:

IOException

read

public long read(ByteBuffer[] dsts,
                 int offset,
                 int length)
          throws IOException

Specified by:

read in interface ScatteringByteChannel

Throws:

IOException

unget

public void unget(Pooled<ByteBuffer> buffer)

Re-queue the given pooled buffer into this channel. This method transfers ownership of the given buffer to this channel. The buffer should be flipped for emptying.

Parameters:

buffer - the buffer to re-queue

suspendReads

public void suspendReads()

Description copied from interface: SuspendableReadChannel

Suspend further read notifications on this channel.

Specified by:

suspendReads in interface SuspendableReadChannel

resumeReads

public void resumeReads()

Description copied from interface: SuspendableReadChannel

Resume reads on this channel. The read listener will be called as soon as there is data available to be read.

Specified by:

resumeReads in interface SuspendableReadChannel

isReadResumed

public boolean isReadResumed()

Description copied from interface: SuspendableReadChannel

Determine whether reads are resumed.

Specified by:

isReadResumed in interface SuspendableReadChannel

Returns:

true if reads are resumed, false if reads are suspended

wakeupReads

public void wakeupReads()

Description copied from interface: SuspendableReadChannel

Resume reads on this channel, and force the read listener to be triggered even if the channel isn't actually readable.

Specified by:

wakeupReads in interface SuspendableReadChannel

shutdownReads

public void shutdownReads()
                   throws IOException

Description copied from interface: SuspendableReadChannel

Places this readable channel at "end of stream". Further reads will result in EOF. Shutting down all directions of a channel will cause CloseableChannel.close() to be called automatically.

Specified by:

shutdownReads in interface SuspendableReadChannel

Throws:

IOException - if an I/O error occurs

awaitReadable

public void awaitReadable()
                   throws IOException

Description copied from interface: SuspendableReadChannel

Block until this channel becomes readable again. This method may return spuriously before the channel becomes readable.

Specified by:

awaitReadable in interface SuspendableReadChannel

Throws:

InterruptedIOException - if the operation is interrupted; the thread's interrupt flag will be set as well

IOException - if an I/O error occurs

awaitReadable

public void awaitReadable(long time,
                          TimeUnit timeUnit)
                   throws IOException

Description copied from interface: SuspendableReadChannel

Block until this channel becomes readable again, or until the timeout expires. This method may return spuriously before the channel becomes readable or the timeout expires.

Specified by:

awaitReadable in interface SuspendableReadChannel

Parameters:

time - the time to wait

timeUnit - the time unit

Throws:

InterruptedIOException - if the operation is interrupted; the thread's interrupt flag will be set as well

IOException - if an I/O error occurs

getReadThread

@Deprecated
public XnioExecutor getReadThread()

Deprecated.

Description copied from interface: SuspendableReadChannel

Get the read thread for this channel.

Specified by:

getReadThread in interface SuspendableReadChannel

Returns:

the thread, or null if none is configured or available

getIoThread

public XnioIoThread getIoThread()

Description copied from interface: CloseableChannel

Get the I/O thread associated with this channel.

Specified by:

getIoThread in interface CloseableChannel

Returns:

the I/O thread associated with this channel

getWorker

public XnioWorker getWorker()

Description copied from interface: CloseableChannel

Get the worker for this channel.

Specified by:

getWorker in interface CloseableChannel

Returns:

the worker

isOpen

public boolean isOpen()

Specified by:

isOpen in interface Channel

close

public void close()
           throws IOException

Description copied from interface: CloseableChannel

Close this channel. When a channel is closed, its close listener is invoked. Invoking this method more than once has no additional effect.

Specified by:

close in interface Closeable

Specified by:

close in interface AutoCloseable

Specified by:

close in interface Channel

Specified by:

close in interface InterruptibleChannel

Specified by:

close in interface CloseableChannel

Throws:

IOException - if the close failed

supportsOption

public boolean supportsOption(Option<?> option)

Description copied from interface: Configurable

Determine whether an option is supported on this channel.

Specified by:

supportsOption in interface Configurable

Parameters:

option - the option

Returns:

true if it is supported

getOption

public <T> T getOption(Option<T> option)
                throws IOException

Description copied from interface: Configurable

Get the value of a channel option.

Specified by:

getOption in interface Configurable

Type Parameters:

T - the type of the option value

Parameters:

option - the option to get

Returns:

the value of the option, or null if it is not set

Throws:

IOException - if an I/O error occurred when reading the option

setOption

public <T> T setOption(Option<T> option,
                       T value)
                throws IllegalArgumentException,
                       IOException

Description copied from interface: Configurable

Set an option for this channel. Unsupported options are ignored.

Specified by:

setOption in interface Configurable

Type Parameters:

T - the type of the option value

Parameters:

option - the option to set

value - the value of the option to set

Returns:

the previous option value, if any

Throws:

IllegalArgumentException - if the value is not acceptable for this option

IOException - if an I/O error occurred when modifying the option

getChannel

public StreamSourceChannel getChannel()

Description copied from interface: WrappedChannel

Get the channel which is wrapped by this object.

Specified by:

getChannel in interface WrappedChannel<StreamSourceChannel>

Returns:

the wrapped channel