001    /*
002     * Licensed to the Apache Software Foundation (ASF) under one or more
003     * contributor license agreements.  See the NOTICE file distributed with
004     * this work for additional information regarding copyright ownership.
005     * The ASF licenses this file to You under the Apache License, Version 2.0
006     * (the "License"); you may not use this file except in compliance with
007     * the License.  You may obtain a copy of the License at
008     * 
009     *      http://www.apache.org/licenses/LICENSE-2.0
010     * 
011     * Unless required by applicable law or agreed to in writing, software
012     * distributed under the License is distributed on an "AS IS" BASIS,
013     * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
014     * See the License for the specific language governing permissions and
015     * limitations under the License.
016     */
017    package org.apache.commons.io.output;
018    
019    import java.io.OutputStream;
020    
021    /**
022     * Proxy stream that prevents the underlying output stream from being closed.
023     * <p>
024     * This class is typically used in cases where an output stream needs to be
025     * passed to a component that wants to explicitly close the stream even if
026     * other components would still use the stream for output.
027     *
028     * @version $Id: CloseShieldOutputStream.java 1304052 2012-03-22 20:55:29Z ggregory $
029     * @since 1.4
030     */
031    public class CloseShieldOutputStream extends ProxyOutputStream {
032    
033        /**
034         * Creates a proxy that shields the given output stream from being
035         * closed.
036         *
037         * @param out underlying output stream
038         */
039        public CloseShieldOutputStream(OutputStream out) {
040            super(out);
041        }
042    
043        /**
044         * Replaces the underlying output stream with a {@link ClosedOutputStream}
045         * sentinel. The original output stream will remain open, but this proxy
046         * will appear closed.
047         */
048        @Override
049        public void close() {
050            out = new ClosedOutputStream();
051        }
052    
053    }