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.IOException;
020    import java.io.OutputStream;
021    
022    /**
023     * Closed output stream. This stream throws an exception on all attempts to
024     * write something to the stream.
025     * <p>
026     * Typically uses of this class include testing for corner cases in methods
027     * that accept an output stream and acting as a sentinel value instead of
028     * a <code>null</code> output stream.
029     *
030     * @version $Id: ClosedOutputStream.java 1304052 2012-03-22 20:55:29Z ggregory $
031     * @since 1.4
032     */
033    public class ClosedOutputStream extends OutputStream {
034        
035        /**
036         * A singleton.
037         */
038        public static final ClosedOutputStream CLOSED_OUTPUT_STREAM = new ClosedOutputStream();
039    
040        /**
041         * Throws an {@link IOException} to indicate that the stream is closed.
042         *
043         * @param b ignored
044         * @throws IOException always thrown
045         */
046        @Override
047        public void write(int b) throws IOException {
048            throw new IOException("write(" + b + ") failed: stream is closed");
049        }
050    
051    }