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 {@link ReadPendingException} will be thrown. * Similarly, if a write method is invoked before a previous write has completed * then {@link 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 {@link java.nio.ByteBuffer 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. * * @see Channels#newInputStream(AsynchronousByteChannel) * @see Channels#newOutputStream(AsynchronousByteChannel) * * @since 1.7 */ public interface AsynchronousByteChannel extends AsynchronousChannel { /** * Reads a sequence of bytes from this channel into the given buffer. * *
This method initiates an operation to read a sequence of bytes from * this channel into the given buffer. The method returns a {@link Future} * representing the pending result of the operation. The result of the * operation, obtained by invoking the {@code Future} 's {@link * Future#get() get} method, is the number of bytes read or {@code -1} if * all bytes have been read and the channel has reached end-of-stream. * *
This method initiates a read operation to read up to r bytes * from the channel, where r is the number of bytes remaining in the * buffer, that is, {@code dst.remaining()} at the time that the read is * attempted. Where r is 0, the read operation completes immediately * with a result of {@code 0} 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 to access the buffer until the operaton 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 {@link ReadPendingException} will be thrown. * *
The handler parameter is used to specify a {@link
* CompletionHandler}. When the read operation completes the handler's
* {@link CompletionHandler#completed completed} method is executed.
*
*
* @param dst
* The buffer into which bytes are to be transferred
* @param attachment
* The object to attach to the I/O operation; can be {@code null}
* @param handler
* The completion handler object; can be {@code null}
*
* @return A Future representing the result of the operation
*
* @throws IllegalArgumentException
* If the buffer is read-only
* @throws ReadPendingException
* If the channel does not allow more than one read to be outstanding
* and a previous read has not completed
*/
Future An invocation of this method of the form c.read(dst)
* behaves in exactly the same manner as the invocation
* This method initiates an operation to write a sequence of bytes to
* this channel from the given buffer. This method returns a {@link
* Future} representing the pending result of the operation. The result
* of the operation, obtained by invoking the Future's {@link
* Future#get() get} method, is the number of bytes written, possibly zero.
*
* This method initiates a write operation to write up to r bytes
* to the channel, where r is the number of bytes remaining in the
* buffer, that is, {@code src.remaining()} at the moment the write is
* attempted. Where r is 0, the write operation completes immediately
* with a result of {@code 0} 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 to access the buffer until the operaton 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 {@link WritePendingException} will be thrown.
*
* The handler parameter is used to specify a {@link
* CompletionHandler}. When the write operation completes the handler's
* {@link CompletionHandler#completed completed} method is executed.
*
* @param src
* The buffer from which bytes are to be retrieved
* @param attachment
* The object to attach to the I/O operation; can be {@code null}
* @param handler
* The completion handler object; can be {@code null}
*
* @return 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
*/
Future An invocation of this method of the form c.write(src)
* behaves in exactly the same manner as the invocation
*
*
* @param dst
* The buffer into which bytes are to be transferred
*
* @return A Future representing the result of the operation
*
* @throws IllegalArgumentException
* If the buffer is read-only
* @throws ReadPendingException
* If the channel does not allow more than one read to be outstanding
* and a previous read has not completed
*/
Future
* c.read(dst, null, null);
*
* @param src
* The buffer from which bytes are to be retrieved
*
* @return 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
*/
Future
* c.write(src, null, null);