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/*
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* Copyright (c) 2000, 2001, Oracle and/or its affiliates. All rights reserved.
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* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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*
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* This code is free software; you can redistribute it and/or modify it
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* under the terms of the GNU General Public License version 2 only, as
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* published by the Free Software Foundation. Oracle designates this
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* particular file as subject to the "Classpath" exception as provided
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* by Oracle in the LICENSE file that accompanied this code.
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*
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* This code is distributed in the hope that it will be useful, but WITHOUT
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* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
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* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
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* version 2 for more details (a copy is included in the LICENSE file that
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* accompanied this code).
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*
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* You should have received a copy of the GNU General Public License version
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* 2 along with this work; if not, write to the Free Software Foundation,
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* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
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*
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* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
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* or visit www.oracle.com if you need additional information or have any
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* questions.
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*/
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package java.nio.channels;
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import java.io.IOException;
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import java.nio.ByteBuffer;
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/**
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* A channel that can write bytes from a sequence of buffers.
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*
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* <p> A <i>gathering</i> write operation writes, in a single invocation, a
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* sequence of bytes from one or more of a given sequence of buffers.
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* Gathering writes are often useful when implementing network protocols or
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* file formats that, for example, group data into segments consisting of one
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* or more fixed-length headers followed by a variable-length body. Similar
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* <i>scattering</i> read operations are defined in the {@link
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* ScatteringByteChannel} interface. </p>
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*
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*
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* @author Mark Reinhold
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* @author JSR-51 Expert Group
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* @since 1.4
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*/
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public interface GatheringByteChannel
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extends WritableByteChannel
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{
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/**
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* Writes a sequence of bytes to this channel from a subsequence of the
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* given buffers.
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*
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* <p> An attempt is made to write up to <i>r</i> bytes to this channel,
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* where <i>r</i> is the total number of bytes remaining in the specified
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* subsequence of the given buffer array, that is,
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*
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* <blockquote><pre>
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* srcs[offset].remaining()
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* + srcs[offset+1].remaining()
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* + ... + srcs[offset+length-1].remaining()</pre></blockquote>
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*
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* at the moment that this method is invoked.
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*
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* <p> Suppose that a byte sequence of length <i>n</i> is written, where
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* <tt>0</tt> <tt><=</tt> <i>n</i> <tt><=</tt> <i>r</i>.
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* Up to the first <tt>srcs[offset].remaining()</tt> bytes of this sequence
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* are written from buffer <tt>srcs[offset]</tt>, up to the next
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* <tt>srcs[offset+1].remaining()</tt> bytes are written from buffer
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* <tt>srcs[offset+1]</tt>, and so forth, until the entire byte sequence is
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* written. As many bytes as possible are written from each buffer, hence
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* the final position of each updated buffer, except the last updated
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* buffer, is guaranteed to be equal to that buffer's limit.
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*
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* <p> Unless otherwise specified, a write operation will return only after
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* writing all of the <i>r</i> requested bytes. Some types of channels,
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* depending upon their state, may write only some of the bytes or possibly
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* none at all. A socket channel in non-blocking mode, for example, cannot
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* write any more bytes than are free in the socket's output buffer.
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*
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* <p> This method may be invoked at any time. If another thread has
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* already initiated a write operation upon this channel, however, then an
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* invocation of this method will block until the first operation is
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* complete. </p>
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*
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* @param srcs
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* The buffers from which bytes are to be retrieved
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*
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* @param offset
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* The offset within the buffer array of the first buffer from
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* which bytes are to be retrieved; must be non-negative and no
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* larger than <tt>srcs.length</tt>
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*
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* @param length
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* The maximum number of buffers to be accessed; must be
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* non-negative and no larger than
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* <tt>srcs.length</tt> - <tt>offset</tt>
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*
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* @return The number of bytes written, possibly zero
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*
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* @throws IndexOutOfBoundsException
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* If the preconditions on the <tt>offset</tt> and <tt>length</tt>
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* parameters do not hold
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*
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* @throws NonWritableChannelException
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* If this channel was not opened for writing
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*
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* @throws ClosedChannelException
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* If this channel is closed
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*
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* @throws AsynchronousCloseException
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* If another thread closes this channel
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* while the write operation is in progress
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*
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* @throws ClosedByInterruptException
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* If another thread interrupts the current thread
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* while the write operation is in progress, thereby
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* closing the channel and setting the current thread's
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* interrupt status
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*
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* @throws IOException
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* If some other I/O error occurs
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*/
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public long write(ByteBuffer[] srcs, int offset, int length)
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throws IOException;
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/**
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* Writes a sequence of bytes to this channel from the given buffers.
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*
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* <p> An invocation of this method of the form <tt>c.write(srcs)</tt>
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* behaves in exactly the same manner as the invocation
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*
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* <blockquote><pre>
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* c.write(srcs, 0, srcs.length);</pre></blockquote>
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*
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* @param srcs
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* The buffers from which bytes are to be retrieved
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*
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* @return The number of bytes written, possibly zero
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*
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* @throws NonWritableChannelException
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* If this channel was not opened for writing
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*
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* @throws ClosedChannelException
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* If this channel is closed
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*
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* @throws AsynchronousCloseException
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* If another thread closes this channel
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* while the write operation is in progress
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*
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* @throws ClosedByInterruptException
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* If another thread interrupts the current thread
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* while the write operation is in progress, thereby
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* closing the channel and setting the current thread's
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* interrupt status
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*
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* @throws IOException
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* If some other I/O error occurs
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*/
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public long write(ByteBuffer[] srcs) throws IOException;
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}
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