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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.io.output;
18  
19  import java.io.IOException;
20  import java.io.OutputStream;
21  
22  /**
23   * Throws an IOException on all attempts to write to the stream.
24   * <p>
25   * Typically uses of this class include testing for corner cases in methods that accept an output stream and acting as a
26   * sentinel value instead of a {@code null} output stream.
27   * </p>
28   *
29   * @since 1.4
30   */
31  public class ClosedOutputStream extends OutputStream {
32  
33      /**
34       * The singleton instance.
35       *
36       * @since 2.12.0
37       */
38      public static final ClosedOutputStream INSTANCE = new ClosedOutputStream();
39  
40      /**
41       * The singleton instance.
42       *
43       * @deprecated Use {@link #INSTANCE}.
44       */
45      @Deprecated
46      public static final ClosedOutputStream CLOSED_OUTPUT_STREAM = INSTANCE;
47  
48      /**
49       * Throws an {@link IOException} to indicate that the stream is closed.
50       *
51       * @throws IOException always thrown
52       */
53      @Override
54      public void flush() throws IOException {
55          throw new IOException("flush() failed: stream is closed");
56      }
57  
58      /**
59       * Throws an {@link IOException} to indicate that the stream is closed.
60       *
61       * @param b ignored
62       * @throws IOException always thrown
63       */
64      @Override
65      public void write(final int b) throws IOException {
66          throw new IOException("write(" + b + ") failed: stream is closed");
67      }
68  }