java.nio.channels.GatheringByteChannel Maven / Gradle / Ivy
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* accompanied this code).
*
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package java.nio.channels;
import java.io.IOException;
import java.nio.ByteBuffer;
/**
* A channel that can write bytes from a sequence of buffers.
*
* A gathering write operation writes, in a single invocation, a
* sequence of bytes from one or more of a given sequence of buffers.
* Gathering writes are often useful when implementing network protocols or
* file formats that, for example, group data into segments consisting of one
* or more fixed-length headers followed by a variable-length body. Similar
* scattering read operations are defined in the {@link
* ScatteringByteChannel} interface.
*
*
* @author Mark Reinhold
* @author JSR-51 Expert Group
* @since 1.4
*/
public interface GatheringByteChannel
extends WritableByteChannel
{
/**
* Writes a sequence of bytes to this channel from a subsequence of the
* given buffers.
*
* An attempt is made to write up to r bytes to this channel,
* where r is the total number of bytes remaining in the specified
* subsequence of the given buffer array, that is,
*
*
* srcs[offset].remaining()
* + srcs[offset+1].remaining()
* + ... + srcs[offset+length-1].remaining()
*
* at the moment that this method is invoked.
*
* Suppose that a byte sequence of length n is written, where
* {@code 0} {@code <=} n {@code <=} r.
* Up to the first {@code srcs[offset].remaining()} bytes of this sequence
* are written from buffer {@code srcs[offset]}, up to the next
* {@code srcs[offset+1].remaining()} bytes are written from buffer
* {@code srcs[offset+1]}, and so forth, until the entire byte sequence is
* written. As many bytes as possible are written from each buffer, hence
* the final position of each updated buffer, except the last updated
* buffer, is guaranteed to be equal to that buffer's limit.
*
*
Unless otherwise specified, a write operation will return only after
* writing all of the r requested bytes. Some types of channels,
* depending upon their state, may write only some of the bytes or possibly
* none at all. A socket channel in non-blocking mode, for example, cannot
* write any more bytes than are free in the socket's output buffer.
*
*
This method may be invoked at any time. If another thread has
* already initiated a write operation upon this channel, however, then an
* invocation of this method will block until the first operation is
* complete.
*
* @param srcs
* The buffers from which bytes are to be retrieved
*
* @param offset
* The offset within the buffer array of the first buffer from
* which bytes are to be retrieved; must be non-negative and no
* larger than {@code srcs.length}
*
* @param length
* The maximum number of buffers to be accessed; must be
* non-negative and no larger than
* {@code srcs.length} - {@code offset}
*
* @return The number of bytes written, possibly zero
*
* @throws IndexOutOfBoundsException
* If the preconditions on the {@code offset} and {@code length}
* parameters do not hold
*
* @throws NonWritableChannelException
* If this channel was not opened for writing
*
* @throws ClosedChannelException
* If this channel is closed
*
* @throws AsynchronousCloseException
* If another thread closes this channel
* while the write operation is in progress
*
* @throws ClosedByInterruptException
* If another thread interrupts the current thread
* while the write operation is in progress, thereby
* closing the channel and setting the current thread's
* interrupt status
*
* @throws IOException
* If some other I/O error occurs
*/
public long write(ByteBuffer[] srcs, int offset, int length)
throws IOException;
/**
* Writes a sequence of bytes to this channel from the given buffers.
*
* An invocation of this method of the form {@code c.write(srcs)}
* behaves in exactly the same manner as the invocation
*
*
* c.write(srcs, 0, srcs.length);
*
* @param srcs
* The buffers from which bytes are to be retrieved
*
* @return The number of bytes written, possibly zero
*
* @throws NonWritableChannelException
* If this channel was not opened for writing
*
* @throws ClosedChannelException
* If this channel is closed
*
* @throws AsynchronousCloseException
* If another thread closes this channel
* while the write operation is in progress
*
* @throws ClosedByInterruptException
* If another thread interrupts the current thread
* while the write operation is in progress, thereby
* closing the channel and setting the current thread's
* interrupt status
*
* @throws IOException
* If some other I/O error occurs
*/
public long write(ByteBuffer[] srcs) throws IOException;
}