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 * Throws an exception on all attempts to write to the stream.
024 * <p>
025 * Typically uses of this class include testing for corner cases in methods that accept an output stream and acting as a
026 * sentinel value instead of a {@code null} output stream.
027 * </p>
028 *
029 * @since 1.4
030 */
031public class ClosedOutputStream extends OutputStream {
032
033    /**
034     * A singleton.
035     */
036    public static final ClosedOutputStream CLOSED_OUTPUT_STREAM = new ClosedOutputStream();
037
038    /**
039     * Throws an {@link IOException} to indicate that the stream is closed.
040     *
041     * @param b ignored
042     * @throws IOException always thrown
043     */
044    @Override
045    public void write(final int b) throws IOException {
046        throw new IOException("write(" + b + ") failed: stream is closed");
047    }
048
049    /**
050     * Throws an {@link IOException} to indicate that the stream is closed.
051     *
052     * @throws IOException always thrown
053     */
054    @Override
055    public void flush() throws IOException {
056        throw new IOException("flush() failed: stream is closed");
057    }
058}