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 * Copyright 2013 Red Hat, Inc. and/or its affiliates.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
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 * See the License for the specific language governing permissions and
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package org.xnio.conduits;

import java.io.IOException;
import java.nio.ByteBuffer;
import java.nio.channels.ClosedChannelException;
import java.nio.channels.FileChannel;
import org.xnio.channels.StreamSourceChannel;

A sink (writable) conduit for byte streams.
Author:
David M. Lloyd/**
 * A sink (writable) conduit for byte streams.
 *
 * @author <a href="mailto:david.lloyd@redhat.com">David M. Lloyd</a>
 */
public interface StreamSinkConduit extends SinkConduit {

    
Transfer bytes into this conduit from the given file.
Params:
src – the file to read from
position – the position within the file from which the transfer is to begin
count – the number of bytes to be transferred
Throws:
IOException – if an I/O error occurs
Returns:
the number of bytes (possibly 0) that were actually transferred/**
     * Transfer bytes into this conduit from the given file.
     *
     * @param src the file to read from
     * @param position the position within the file from which the transfer is to begin
     * @param count the number of bytes to be transferred
     * @return the number of bytes (possibly 0) that were actually transferred
     * @throws IOException if an I/O error occurs
     */
    long transferFrom(FileChannel src, long position, long count) throws IOException;

    
Transfers bytes from the given channel source. On entry, throughBuffer will be cleared. On exit, the buffer will be flipped for emptying, and may be empty or may contain data. If this method returns a value less than count, then the remaining data in throughBuffer may contain data read from source which must be written to this channel to complete the operation. 
Params:
source – the source to read from
count – the number of bytes to be transferred
throughBuffer – the buffer to copy through.
Throws:
IOException – if an I/O error occurs
Returns:
the number of bytes (possibly 0) that were actually transferred, or -1 if the end of input was reached/**
     * Transfers bytes from the given channel source.  On entry, {@code throughBuffer} will be cleared.  On exit, the
     * buffer will be flipped for emptying, and may be empty or may contain data.  If this method returns a value less
     * than {@code count}, then the remaining data in {@code throughBuffer} may contain data read from {@code source}
     * which must be written to this channel to complete the operation.
     *
     * @param source the source to read from
     * @param count the number of bytes to be transferred
     * @param throughBuffer the buffer to copy through.
     * @return the number of bytes (possibly 0) that were actually transferred, or -1 if the end of input was reached
     * @throws IOException if an I/O error occurs
     */
    long transferFrom(StreamSourceChannel source, long count, ByteBuffer throughBuffer) throws IOException;

    
Writes a sequence of bytes to this conduit from the given buffer.
Params:
src – the buffer containing data to write
Throws:
ClosedChannelException – if this conduit's SinkConduit.terminateWrites() method was previously called
IOException – if an error occurs
Returns:
the number of bytes written, possibly 0/**
     * Writes a sequence of bytes to this conduit from the given buffer.
     *
     * @param src the buffer containing data to write
     * @return the number of bytes written, possibly 0
     * @throws ClosedChannelException if this conduit's {@link #terminateWrites()} method was previously called
     * @throws IOException if an error occurs
     */
    int write(ByteBuffer src) throws IOException;

    
Writes a sequence of bytes to this conduit from the given buffers.
Params:
srcs – the buffers containing data to write
offs – the offset into the buffer array
len – the number of buffers to write
Throws:
ClosedChannelException – if this conduit's SinkConduit.terminateWrites() method was previously called
IOException – if an error occurs
Returns:
the number of bytes written, possibly 0/**
     * Writes a sequence of bytes to this conduit from the given buffers.
     *
     * @param srcs the buffers containing data to write
     * @param offs the offset into the buffer array
     * @param len the number of buffers to write
     * @return the number of bytes written, possibly 0
     * @throws ClosedChannelException if this conduit's {@link #terminateWrites()} method was previously called
     * @throws IOException if an error occurs
     */
    long write(ByteBuffer[] srcs, int offs, int len) throws IOException;


    
Writes some data to the conduit, with the same semantics as write(ByteBuffer). If all the data is written out then the conduit will have its writes terminated. Semantically this method is equivalent to: 
    int rem = src.remaining();
    int written = conduit.write(src);
    if(written == rem) {
        conduit.terminateWrites()
    }

Params:
src – The data to write
Returns:
The amount of data that was actually written./**
     *
     * Writes some data to the conduit, with the same semantics as
     * {@link #write(java.nio.ByteBuffer)}. If all the data is written
     * out then the conduit will have its writes terminated. Semantically this
     * method is equivalent to:
     *
     * <code>
     *     int rem = src.remaining();
     *     int written = conduit.write(src);
     *     if(written == rem) {
     *         conduit.terminateWrites()
     *     }
     * </code>
     *
     * @param src The data to write
     * @return The amount of data that was actually written.
     */
    public int writeFinal(ByteBuffer src) throws IOException;

    
Writes some data to the conduit, with the same semantics as write(ByteBuffer[], int, int). If all the data is written out then the conduit will have its writes terminated. 
Params:
srcs – 
        The buffers from which bytes are to be retrieved
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 srcs.length
length – 
        The maximum number of buffers to be accessed; must be
        non-negative and no larger than
        srcs.length - offset
Returns:
The amount of data that was actually written/**
     *
     * Writes some data to the conduit, with the same semantics as
     * {@link #write(java.nio.ByteBuffer[], int, int)}. If all the data is written
     * out then the conduit will have its writes terminated.
     *
     *
     * @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 <tt>srcs.length</tt>
     *
     * @param  length
     *         The maximum number of buffers to be accessed; must be
     *         non-negative and no larger than
     *         <tt>srcs.length</tt>&nbsp;-&nbsp;<tt>offset</tt>
     *
     * @return The amount of data that was actually written
     */
    public long writeFinal(ByteBuffer[] srcs, int offset, int length) throws IOException;
}