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1   /*
2    *  Licensed to the Apache Software Foundation (ASF) under one or more
3    *  contributor license agreements.  See the NOTICE file distributed with
4    *  this work for additional information regarding copyright ownership.
5    *  The ASF licenses this file to You under the Apache License, Version 2.0
6    *  (the "License"); you may not use this file except in compliance with
7    *  the License.  You may obtain a copy of the License at
8    *
9    *      http://www.apache.org/licenses/LICENSE-2.0
10   *
11   *  Unless required by applicable law or agreed to in writing, software
12   *  distributed under the License is distributed on an "AS IS" BASIS,
13   *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
14   *  See the License for the specific language governing permissions and
15   *  limitations under the License.
16   */
17  package org.apache.commons.compress.parallel;
18  
19  import java.io.Closeable;
20  import java.io.IOException;
21  import java.io.InputStream;
22  
23  /**
24   * <p>
25   * Store intermediate payload in a scatter-gather scenario. Multiple threads write their payload to a backing store, which can subsequently be reversed to an
26   * {@link InputStream} to be used as input in the gather phase.
27   * </p>
28   *
29   * <p>
30   * 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
31   * delete files.
32   * </p>
33   *
34   * @since 1.10
35   */
36  public interface ScatterGatherBackingStore extends Closeable {
37  
38      /**
39       * Closes this backing store for further writing.
40       *
41       * @throws IOException when something fails
42       */
43      void closeForWriting() throws IOException;
44  
45      /**
46       * An input stream that contains the scattered payload
47       *
48       * @return An InputStream, should be closed by the caller of this method.
49       * @throws IOException when something fails
50       */
51      InputStream getInputStream() throws IOException;
52  
53      /**
54       * Writes a piece of payload.
55       *
56       * @param data   the data to write
57       * @param offset offset inside data to start writing from
58       * @param length the amount of data to write
59       * @throws IOException when something fails
60       */
61      void writeOut(byte[] data, int offset, int length) throws IOException;
62  }