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