001/*
002 * Licensed to the Apache Software Foundation (ASF) under one
003 * or more contributor license agreements.  See the NOTICE file
004 * distributed with this work for additional information
005 * regarding copyright ownership.  The ASF licenses this file
006 * to you under the Apache License, Version 2.0 (the
007 * "License"); you may not use this file except in compliance
008 * with the License.  You may obtain a copy of the License at
009 *
010 *   https://www.apache.org/licenses/LICENSE-2.0
011 *
012 * Unless required by applicable law or agreed to in writing,
013 * software distributed under the License is distributed on an
014 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
015 * KIND, either express or implied.  See the License for the
016 * specific language governing permissions and limitations
017 * under the License.
018 */
019package org.apache.commons.compress.parallel;
020
021import java.io.Closeable;
022import java.io.IOException;
023import java.io.InputStream;
024
025/**
026 * Store intermediate payload in a scatter-gather scenario. Multiple threads write their payload to a backing store, which can subsequently be reversed to an
027 * {@link InputStream} to be used as input in the gather phase.
028 * <p>
029 * It is the responsibility of the allocator of an instance of this class to close this. Closing it should clear off any allocated structures and preferably
030 * delete files.
031 * </p>
032 *
033 * @since 1.10
034 */
035public interface ScatterGatherBackingStore extends Closeable {
036
037    /**
038     * Closes this backing store for further writing.
039     *
040     * @throws IOException if an I/O error occurs.
041     */
042    void closeForWriting() throws IOException;
043
044    /**
045     * An input stream that contains the scattered payload
046     *
047     * @return An InputStream, should be closed by the caller of this method.
048     * @throws IOException if an I/O error occurs.
049     */
050    InputStream getInputStream() throws IOException;
051
052    /**
053     * Writes a piece of payload.
054     *
055     * @param data   the data to write
056     * @param offset offset inside data to start writing from
057     * @param length the amount of data to write
058     * @throws IOException if an I/O error occurs.
059     */
060    void writeOut(byte[] data, int offset, int length) throws IOException;
061}