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 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

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 * 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

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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.

 *

 * <p> A <i>gathering</i> 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

 * <i>scattering</i> read operations are defined in the {@link

 * ScatteringByteChannel} interface.  </p>

 *

 *

 * @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.

     *

     * <p> An attempt is made to write up to <i>r</i> bytes to this channel,

     * where <i>r</i> is the total number of bytes remaining in the specified

     * subsequence of the given buffer array, that is,

     *

     * <blockquote><pre>

     * srcs[offset].remaining()

     *     + srcs[offset+1].remaining()

     *     + ... + srcs[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 written, where

     * {@code 0}&nbsp;{@code <=}&nbsp;<i>n</i>&nbsp;{@code <=}&nbsp;<i>r</i>.

     * 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.

     *

     * <p> Unless otherwise specified, a write operation will return only after

     * writing all of the <i>r</i> 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.

     *

     * <p> 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. </p>

     *

     * @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.

     *

     * <p> An invocation of this method of the form {@code c.write(srcs)}

     * behaves in exactly the same manner as the invocation

     *

     * <blockquote><pre>

     * c.write(srcs, 0, srcs.length);</pre></blockquote>

     *

     * @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;

}