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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.input;
18  
19  import java.io.InputStream;
20  
21  /**
22   * Proxy stream that prevents the underlying input stream from being closed.
23   * <p>
24   * This class is typically used in cases where an input stream needs to be
25   * passed to a component that wants to explicitly close the stream even if more
26   * input would still be available to other components.
27   * </p>
28   *
29   * @since 1.4
30   */
31  public class CloseShieldInputStream extends ProxyInputStream {
32  
33      /**
34       * Constructs a proxy that shields the given input stream from being closed.
35       *
36       * @param inputStream the input stream to wrap
37       * @return the created proxy
38       * @since 2.9.0
39       */
40      public static CloseShieldInputStream wrap(final InputStream inputStream) {
41          return new CloseShieldInputStream(inputStream);
42      }
43  
44      /**
45       * Constructs a proxy that shields the given input stream from being closed.
46       *
47       * @param inputStream underlying input stream
48       * @deprecated Using this constructor prevents IDEs from warning if the
49       *             underlying input stream is never closed. Use
50       *             {@link #wrap(InputStream)} instead.
51       */
52      @Deprecated
53      public CloseShieldInputStream(final InputStream inputStream) {
54          super(inputStream);
55      }
56  
57      /**
58       * Replaces the underlying input stream with a {@link ClosedInputStream}
59       * sentinel. The original input stream will remain open, but this proxy will
60       * appear closed.
61       */
62      @Override
63      public void close() {
64          in = ClosedInputStream.INSTANCE;
65      }
66  
67  }