    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 *      https://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 IOException 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 sentinel value instead of a
    026 * {@code null} output stream.
    027 * </p>
    028 *
    029 * @since 1.4
    030 */
    031public class ClosedOutputStream extends OutputStream {
    032
    033    /**
    034     * The singleton instance.
    035     *
    036     * @since 2.12.0
    037     */
    038    public static final ClosedOutputStream INSTANCE = new ClosedOutputStream();
    039
    040    /**
    041     * The singleton instance.
    042     *
    043     * @deprecated Use {@link #INSTANCE}.
    044     */
    045    @Deprecated
    046    public static final ClosedOutputStream CLOSED_OUTPUT_STREAM = INSTANCE;
    047
    048    /**
    049     * Construct a new instance.
    050     */
    051    public ClosedOutputStream() {
    052        // empty
    053    }
    054
    055    /**
    056     * Throws an {@link IOException} to indicate that the stream is closed.
    057     *
    058     * @throws IOException always thrown
    059     */
    060    @Override
    061    public void flush() throws IOException {
    062        throw new IOException("flush() failed: stream is closed");
    063    }
    064
    065    /**
    066     * Throws an {@link IOException} to indicate that the stream is closed.
    067     *
    068     * @param b   ignored
    069     * @param off ignored
    070     * @param len ignored
    071     * @throws IOException always thrown
    072     */
    073    @Override
    074    public void write(final byte b[], final int off, final int len) throws IOException {
    075        throw new IOException("write(byte[], int, int) failed: stream is closed");
    076    }
    077
    078    /**
    079     * Throws an {@link IOException} to indicate that the stream is closed.
    080     *
    081     * @param b ignored
    082     * @throws IOException always thrown
    083     */
    084    @Override
    085    public void write(final int b) throws IOException {
    086        throw new IOException("write(int) failed: stream is closed");
    087    }
    088}