001/*
002 * ====================================================================
003 * Licensed to the Apache Software Foundation (ASF) under one
004 * or more contributor license agreements.  See the NOTICE file
005 * distributed with this work for additional information
006 * regarding copyright ownership.  The ASF licenses this file
007 * to you under the Apache License, Version 2.0 (the
008 * "License"); you may not use this file except in compliance
009 * with the License.  You may obtain a copy of the License at
010 *
011 *   http://www.apache.org/licenses/LICENSE-2.0
012 *
013 * Unless required by applicable law or agreed to in writing,
014 * software distributed under the License is distributed on an
015 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
016 * KIND, either express or implied.  See the License for the
017 * specific language governing permissions and limitations
018 * under the License.
019 * ====================================================================
020 *
021 * This software consists of voluntary contributions made by many
022 * individuals on behalf of the Apache Software Foundation.  For more
023 * information on the Apache Software Foundation, please see
024 * <http://www.apache.org/>.
025 *
026 */
027
028package org.apache.http.nio;
029
030import java.io.IOException;
031import java.nio.channels.FileChannel;
032
033/**
034 * A content decoder capable of transferring data directly to a {@link FileChannel}
035 *
036 * @since 4.0
037 */
038public interface FileContentDecoder extends ContentDecoder {
039
040    /**
041     * Transfers a portion of entity content from the underlying network channel
042     * into the given file channel.<br>
043     *
044     * <b>Warning</b>: Many implementations cannot write beyond the length of the file.
045     *             If the position exceeds the channel's size, some implementations
046     *             may throw an IOException.
047     *
048     * @param  dst the target FileChannel to transfer data into.
049     * @param  position
050     *         The position within the file at which the transfer is to begin;
051     *         must be non-negative.
052     *         <b>Must be less than or equal to the size of the file</b>
053     * @param  count
054     *         The maximum number of bytes to be transferred; must be
055     *         non-negative
056     * @throws IOException if some I/O error occurs.
057     * @return  The number of bytes, possibly zero,
058     *          that were actually transferred
059     */
060    long transfer(FileChannel dst, long position, long count) throws IOException;
061
062}