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 */
017package org.apache.commons.io.output;
018
019import java.io.IOException;
020import 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} output stream.
029 *
030 * @since 1.4
031 */
032public class ClosedOutputStream extends OutputStream {
033
034    /**
035     * A singleton.
036     */
037    public static final ClosedOutputStream CLOSED_OUTPUT_STREAM = new ClosedOutputStream();
038
039    /**
040     * Throws an {@link IOException} to indicate that the stream is closed.
041     *
042     * @param b ignored
043     * @throws IOException always thrown
044     */
045    @Override
046    public void write(final int b) throws IOException {
047        throw new IOException("write(" + b + ") failed: stream is closed");
048    }
049
050    /**
051     * Throws an {@link IOException} to indicate that the stream is closed.
052     *
053     * @throws IOException always thrown
054     */
055    @Override
056    public void flush() throws IOException {
057        throw new IOException("flush() failed: stream is closed");
058    }
059}