    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 659817 2008-05-24 13:23:10Z niallp $
    031     * @since Commons IO 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    }