You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
214 lines
9.1 KiB
214 lines
9.1 KiB
/*
|
|
* Copyright (c) 2007, 2013, Oracle and/or its affiliates. All rights reserved.
|
|
* ORACLE PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
|
|
*
|
|
*
|
|
*
|
|
*
|
|
*
|
|
*
|
|
*
|
|
*
|
|
*
|
|
*
|
|
*
|
|
*
|
|
*
|
|
*
|
|
*
|
|
*
|
|
*
|
|
*
|
|
*
|
|
*
|
|
*/
|
|
|
|
package java.nio.channels;
|
|
|
|
import java.nio.ByteBuffer;
|
|
import java.util.concurrent.Future;
|
|
|
|
/**
|
|
* An asynchronous channel that can read and write bytes.
|
|
*
|
|
* <p> 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.
|
|
*
|
|
* <p> 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.
|
|
*
|
|
* <p> This method initiates an asynchronous read operation to read a
|
|
* sequence of bytes from this channel into the given buffer. The {@code
|
|
* 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 {@code -1} if no bytes could be
|
|
* read because the channel has reached end-of-stream.
|
|
*
|
|
* <p> The read operation may read up to <i>r</i> bytes from the channel,
|
|
* where <i>r</i> is the number of bytes remaining in the buffer, that is,
|
|
* {@code dst.remaining()} at the time that the read is attempted. Where
|
|
* <i>r</i> is 0, the read operation completes immediately with a result of
|
|
* {@code 0} without initiating an I/O operation.
|
|
*
|
|
* <p> Suppose that a byte sequence of length <i>n</i> is read, where
|
|
* <tt>0</tt> <tt><</tt> <i>n</i> <tt><=</tt> <i>r</i>.
|
|
* This byte sequence will be transferred into the buffer so that the first
|
|
* byte in the sequence is at index <i>p</i> and the last byte is at index
|
|
* <i>p</i> <tt>+</tt> <i>n</i> <tt>-</tt> <tt>1</tt>,
|
|
* where <i>p</i> is the buffer's position at the moment the read is
|
|
* performed. Upon completion the buffer's position will be equal to
|
|
* <i>p</i> <tt>+</tt> <i>n</i>; its limit will not have changed.
|
|
*
|
|
* <p> 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.
|
|
*
|
|
* <p> 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.
|
|
*
|
|
* @param <A>
|
|
* The type of the attachment
|
|
* @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
|
|
*
|
|
* @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
|
|
* @throws ShutdownChannelGroupException
|
|
* If the channel is associated with a {@link AsynchronousChannelGroup
|
|
* group} that has terminated
|
|
*/
|
|
<A> void read(ByteBuffer dst,
|
|
A attachment,
|
|
CompletionHandler<Integer,? super A> handler);
|
|
|
|
/**
|
|
* Reads a sequence of bytes from this channel into the given buffer.
|
|
*
|
|
* <p> 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 {@link
|
|
* #read(ByteBuffer,Object,CompletionHandler)
|
|
* read(ByteBuffer,Object,CompletionHandler)} method except that instead
|
|
* of specifying a completion handler, this method returns a {@code Future}
|
|
* representing the pending result. The {@code Future}'s {@link Future#get()
|
|
* get} method returns the number of bytes read or {@code -1} if no bytes
|
|
* could be read because the channel has reached end-of-stream.
|
|
*
|
|
* @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<Integer> read(ByteBuffer dst);
|
|
|
|
/**
|
|
* Writes a sequence of bytes to this channel from the given buffer.
|
|
*
|
|
* <p> This method initiates an asynchronous write operation to write a
|
|
* sequence of bytes to this channel from the given buffer. The {@code
|
|
* 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.
|
|
*
|
|
* <p> The write operation may write up to <i>r</i> bytes to the channel,
|
|
* where <i>r</i> is the number of bytes remaining in the buffer, that is,
|
|
* {@code src.remaining()} at the time that the write is attempted. Where
|
|
* <i>r</i> is 0, the write operation completes immediately with a result of
|
|
* {@code 0} without initiating an I/O operation.
|
|
*
|
|
* <p> Suppose that a byte sequence of length <i>n</i> is written, where
|
|
* <tt>0</tt> <tt><</tt> <i>n</i> <tt><=</tt> <i>r</i>.
|
|
* This byte sequence will be transferred from the buffer starting at index
|
|
* <i>p</i>, where <i>p</i> is the buffer's position at the moment the
|
|
* write is performed; the index of the last byte written will be
|
|
* <i>p</i> <tt>+</tt> <i>n</i> <tt>-</tt> <tt>1</tt>.
|
|
* Upon completion the buffer's position will be equal to
|
|
* <i>p</i> <tt>+</tt> <i>n</i>; its limit will not have changed.
|
|
*
|
|
* <p> 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.
|
|
*
|
|
* <p> 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.
|
|
*
|
|
* @param <A>
|
|
* The type of the attachment
|
|
* @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
|
|
*
|
|
* @throws WritePendingException
|
|
* If the channel does not allow more than one write to be outstanding
|
|
* and a previous write has not completed
|
|
* @throws ShutdownChannelGroupException
|
|
* If the channel is associated with a {@link AsynchronousChannelGroup
|
|
* group} that has terminated
|
|
*/
|
|
<A> void write(ByteBuffer src,
|
|
A attachment,
|
|
CompletionHandler<Integer,? super A> handler);
|
|
|
|
/**
|
|
* Writes a sequence of bytes to this channel from the given buffer.
|
|
*
|
|
* <p> 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 {@link
|
|
* #write(ByteBuffer,Object,CompletionHandler)
|
|
* write(ByteBuffer,Object,CompletionHandler)} method except that instead
|
|
* of specifying a completion handler, this method returns a {@code Future}
|
|
* representing the pending result. The {@code Future}'s {@link Future#get()
|
|
* get} method returns the number of bytes written.
|
|
*
|
|
* @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<Integer> write(ByteBuffer src);
|
|
}
|