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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.OutputStream;
20  
21  /**
22   * Proxy stream that prevents the underlying output stream from being closed.
23   * <p>
24   * This class is typically used in cases where an output stream needs to be
25   * passed to a component that wants to explicitly close the stream even if
26   * other components would still use the stream for output.
27   *
28   * @version $Id: CloseShieldOutputStream.java 1415850 2012-11-30 20:51:39Z ggregory $
29   * @since 1.4
30   */
31  public class CloseShieldOutputStream extends ProxyOutputStream {
32  
33      /**
34       * Creates a proxy that shields the given output stream from being
35       * closed.
36       *
37       * @param out underlying output stream
38       */
39      public CloseShieldOutputStream(final OutputStream out) {
40          super(out);
41      }
42  
43      /**
44       * Replaces the underlying output stream with a {@link ClosedOutputStream}
45       * sentinel. The original output stream will remain open, but this proxy
46       * will appear closed.
47       */
48      @Override
49      public void close() {
50          out = new ClosedOutputStream();
51      }
52  
53  }