Interface AsynchronousByteChannel
- All Superinterfaces:
AsynchronousChannel
,AutoCloseable
,Channel
,Closeable
- All Known Implementing Classes:
AsynchronousSocketChannel
Some channels may not allow more than one read or write to be outstanding
at any given time. If a thread invokes a read method before a previous read
operation has completed then a ReadPendingException
will be thrown.
Similarly, if a write method is invoked before a previous write has completed
then WritePendingException
is thrown. Whether or not other kinds of
I/O operations may proceed concurrently with a read operation depends upon
the type of the channel.
Note that ByteBuffers
are not safe for use by
multiple concurrent threads. When a read or write operation is initiated then
care must be taken to ensure that the buffer is not accessed until the
operation completes.
- Since:
- 1.7
- See Also:
-
Method Summary
Modifier and TypeMethodDescriptionread
(ByteBuffer dst) Reads a sequence of bytes from this channel into the given buffer.<A> void
read
(ByteBuffer dst, A attachment, CompletionHandler<Integer, ? super A> handler) Reads a sequence of bytes from this channel into the given buffer.write
(ByteBuffer src) Writes a sequence of bytes to this channel from the given buffer.<A> void
write
(ByteBuffer src, A attachment, CompletionHandler<Integer, ? super A> handler) Writes a sequence of bytes to this channel from the given buffer.Methods declared in interface java.nio.channels.AsynchronousChannel
close
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Method Details
-
read
Reads a sequence of bytes from this channel into the given buffer.This method initiates an asynchronous read operation to read a sequence of bytes from this channel into the given buffer. The
handler
parameter is a completion handler that is invoked when the read operation completes (or fails). The result passed to the completion handler is the number of bytes read or-1
if no bytes could be read because the channel has reached end-of-stream.The read operation may read up to r bytes from the channel, where r is the number of bytes remaining in the buffer, that is,
dst.remaining()
at the time that the read is attempted. Where r is 0, the read operation completes immediately with a result of0
without initiating an I/O operation.Suppose that a byte sequence of length n is read, where
0
<
n<=
r. This byte sequence will be transferred into the buffer so that the first byte in the sequence is at index p and the last byte is at index p+
n-
1
, where p is the buffer's position at the moment the read is performed. Upon completion the buffer's position will be equal to p+
n; its limit will not have changed.Buffers are not safe for use by multiple concurrent threads so care should be taken to not access the buffer until the operation has completed.
This method may be invoked at any time. Some channel types may not allow more than one read to be outstanding at any given time. If a thread initiates a read operation before a previous read operation has completed then a
ReadPendingException
will be thrown.- Type Parameters:
A
- The type of the attachment- Parameters:
dst
- The buffer into which bytes are to be transferredattachment
- The object to attach to the I/O operation; can benull
handler
- The completion handler- Throws:
IllegalArgumentException
- If the buffer is read-onlyReadPendingException
- If the channel does not allow more than one read to be outstanding and a previous read has not completedShutdownChannelGroupException
- If the channel is associated with agroup
that has terminated
-
read
Reads a sequence of bytes from this channel into the given buffer.This method initiates an asynchronous read operation to read a sequence of bytes from this channel into the given buffer. The method behaves in exactly the same manner as the
read(ByteBuffer,Object,CompletionHandler)
method except that instead of specifying a completion handler, this method returns aFuture
representing the pending result. TheFuture
'sget
method returns the number of bytes read or-1
if no bytes could be read because the channel has reached end-of-stream.- Parameters:
dst
- The buffer into which bytes are to be transferred- Returns:
- A Future representing the result of the operation
- Throws:
IllegalArgumentException
- If the buffer is read-onlyReadPendingException
- If the channel does not allow more than one read to be outstanding and a previous read has not completed
-
write
Writes a sequence of bytes to this channel from the given buffer.This method initiates an asynchronous write operation to write a sequence of bytes to this channel from the given buffer. The
handler
parameter is a completion handler that is invoked when the write operation completes (or fails). The result passed to the completion handler is the number of bytes written.The write operation may write up to r bytes to the channel, where r is the number of bytes remaining in the buffer, that is,
src.remaining()
at the time that the write is attempted. Where r is 0, the write operation completes immediately with a result of0
without initiating an I/O operation.Suppose that a byte sequence of length n is written, where
0
<
n<=
r. This byte sequence will be transferred from the buffer starting at index p, where p is the buffer's position at the moment the write is performed; the index of the last byte written will be p+
n-
1
. Upon completion the buffer's position will be equal to p+
n; its limit will not have changed.Buffers are not safe for use by multiple concurrent threads so care should be taken to not access the buffer until the operation has completed.
This method may be invoked at any time. Some channel types may not allow more than one write to be outstanding at any given time. If a thread initiates a write operation before a previous write operation has completed then a
WritePendingException
will be thrown.- Type Parameters:
A
- The type of the attachment- Parameters:
src
- The buffer from which bytes are to be retrievedattachment
- The object to attach to the I/O operation; can benull
handler
- The completion handler object- Throws:
WritePendingException
- If the channel does not allow more than one write to be outstanding and a previous write has not completedShutdownChannelGroupException
- If the channel is associated with agroup
that has terminated
-
write
Writes a sequence of bytes to this channel from the given buffer.This method initiates an asynchronous write operation to write a sequence of bytes to this channel from the given buffer. The method behaves in exactly the same manner as the
write(ByteBuffer,Object,CompletionHandler)
method except that instead of specifying a completion handler, this method returns aFuture
representing the pending result. TheFuture
'sget
method returns the number of bytes written.- Parameters:
src
- The buffer from which bytes are to be retrieved- Returns:
- A Future representing the result of the operation
- Throws:
WritePendingException
- If the channel does not allow more than one write to be outstanding and a previous write has not completed
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