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* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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* 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
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*
* 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.
*
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package java.nio.channels;
import java.io.IOException;
import java.nio.ByteBuffer;
/** {@collect.stats}
* A channel that can read bytes into a sequence of buffers.
*
* <p> A <i>scattering</i> 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
* <i>gathering</i> write operations are defined in the {@link
* GatheringByteChannel} interface. </p>
*
*
* @author Mark Reinhold
* @author JSR-51 Expert Group
* @since 1.4
*/
public interface ScatteringByteChannel
extends ReadableByteChannel
{
/** {@collect.stats}
* Reads a sequence of bytes from this channel into a subsequence of the
* given buffers.
*
* <p> An invocation of this method attempts to read up to <i>r</i> bytes
* from this channel, where <i>r</i> is the total number of bytes remaining
* the specified subsequence of the given buffer array, that is,
*
* <blockquote><pre>
* dsts[offset].remaining()
* + dsts[offset+1].remaining()
* + ... + dsts[offset+length-1].remaining()</pre></blockquote>
*
* at the moment that this method is invoked.
*
* <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>.
* Up to the first <tt>dsts[offset].remaining()</tt> bytes of this sequence
* are transferred into buffer <tt>dsts[offset]</tt>, up to the next
* <tt>dsts[offset+1].remaining()</tt> bytes are transferred into buffer
* <tt>dsts[offset+1]</tt>, 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.
*
* <p> 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. </p>
*
* @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 <tt>dsts.length</tt>
*
* @param length
* The maximum number of buffers to be accessed; must be
* non-negative and no larger than
* <tt>dsts.length</tt> - <tt>offset</tt>
*
* @return The number of bytes read, possibly zero,
* or <tt>-1</tt> if the channel has reached end-of-stream
*
* @throws IndexOutOfBoundsException
* If the preconditions on the <tt>offset</tt> and <tt>length</tt>
* 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;
/** {@collect.stats}
* Reads a sequence of bytes from this channel into the given buffers.
*
* <p> An invocation of this method of the form <tt>c.read(dsts)</tt>
* behaves in exactly the same manner as the invocation
*
* <blockquote><pre>
* c.read(dsts, 0, dsts.length);</pre></blockquote>
*
* @param dsts
* The buffers into which bytes are to be transferred
*
* @return The number of bytes read, possibly zero,
* or <tt>-1</tt> 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;
}