    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 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     * Throws an {@link IOException} to indicate that the stream is closed.
    050     *
    051     * @throws IOException always thrown
    052     */
    053    @Override
    054    public void flush() throws IOException {
    055        throw new IOException("flush() failed: stream is closed");
    056    }
    057
    058    /**
    059     * Throws an {@link IOException} to indicate that the stream is closed.
    060     *
    061     * @param b   ignored
    062     * @param off ignored
    063     * @param len ignored
    064     * @throws IOException always thrown
    065     */
    066    @Override
    067    public void write(final byte b[], final int off, final int len) throws IOException {
    068        throw new IOException("write(byte[], int, int) failed: stream is closed");
    069    }
    070
    071    /**
    072     * Throws an {@link IOException} to indicate that the stream is closed.
    073     *
    074     * @param b ignored
    075     * @throws IOException always thrown
    076     */
    077    @Override
    078    public void write(final int b) throws IOException {
    079        throw new IOException("write(int) failed: stream is closed");
    080    }
    081}