META-INF.modules.java.base.classes.java.nio.channels.ScatteringByteChannel Maven / Gradle / Ivy
Show all versions of java.base Show documentation
/*
* Copyright (c) 2000, 2006, Oracle and/or its affiliates. All rights reserved.
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
*
* This code is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License version 2 only, as
* published by the Free Software Foundation. Oracle designates this
* particular file as subject to the "Classpath" exception as provided
* by Oracle in the LICENSE file that accompanied this code.
*
* This code is distributed in the hope that it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
* version 2 for more details (a copy is included in the LICENSE file that
* accompanied this code).
*
* You should have received a copy of the GNU General Public License version
* 2 along with this work; if not, write to the Free Software Foundation,
* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
*
* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
* or visit www.oracle.com if you need additional information or have any
* questions.
*/
package java.nio.channels;
import java.io.IOException;
import java.nio.ByteBuffer;
/**
* A channel that can read bytes into a sequence of buffers.
*
* A scattering read operation reads, in a single invocation, a
* sequence of bytes into one or more of a given sequence of buffers.
* Scattering reads 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
* gathering write operations are defined in the {@link
* GatheringByteChannel} interface.
*
*
* @author Mark Reinhold
* @author JSR-51 Expert Group
* @since 1.4
*/
public interface ScatteringByteChannel
extends ReadableByteChannel
{
/**
* Reads a sequence of bytes from this channel into a subsequence of the
* given buffers.
*
* An invocation of this method attempts to read up to r bytes
* from this channel, where r is the total number of bytes remaining
* the specified subsequence of the given buffer array, that is,
*
*
* dsts[offset].remaining()
* + dsts[offset+1].remaining()
* + ... + dsts[offset+length-1].remaining()
*
* at the moment that this method is invoked.
*
* Suppose that a byte sequence of length n is read, where
* {@code 0} {@code <=} n {@code <=} r.
* Up to the first {@code dsts[offset].remaining()} bytes of this sequence
* are transferred into buffer {@code dsts[offset]}, up to the next
* {@code dsts[offset+1].remaining()} bytes are transferred into buffer
* {@code dsts[offset+1]}, and so forth, until the entire byte sequence
* is transferred into the given buffers. As many bytes as possible are
* transferred into 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.
*
*
This method may be invoked at any time. If another thread has
* already initiated a read operation upon this channel, however, then an
* invocation of this method will block until the first operation is
* complete.
*
* @param dsts
* The buffers into which bytes are to be transferred
*
* @param offset
* The offset within the buffer array of the first buffer into
* which bytes are to be transferred; must be non-negative and no
* larger than {@code dsts.length}
*
* @param length
* The maximum number of buffers to be accessed; must be
* non-negative and no larger than
* {@code dsts.length} - {@code offset}
*
* @return The number of bytes read, possibly zero,
* or {@code -1} if the channel has reached end-of-stream
*
* @throws IndexOutOfBoundsException
* If the preconditions on the {@code offset} and {@code length}
* parameters do not hold
*
* @throws NonReadableChannelException
* If this channel was not opened for reading
*
* @throws ClosedChannelException
* If this channel is closed
*
* @throws AsynchronousCloseException
* If another thread closes this channel
* while the read operation is in progress
*
* @throws ClosedByInterruptException
* If another thread interrupts the current thread
* while the read 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 read(ByteBuffer[] dsts, int offset, int length)
throws IOException;
/**
* Reads a sequence of bytes from this channel into the given buffers.
*
* An invocation of this method of the form {@code c.read(dsts)}
* behaves in exactly the same manner as the invocation
*
*
* c.read(dsts, 0, dsts.length);
*
* @param dsts
* The buffers into which bytes are to be transferred
*
* @return The number of bytes read, possibly zero,
* or {@code -1} if the channel has reached end-of-stream
*
* @throws NonReadableChannelException
* If this channel was not opened for reading
*
* @throws ClosedChannelException
* If this channel is closed
*
* @throws AsynchronousCloseException
* If another thread closes this channel
* while the read operation is in progress
*
* @throws ClosedByInterruptException
* If another thread interrupts the current thread
* while the read 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 read(ByteBuffer[] dsts) throws IOException;
}