    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 */
    017
    018package org.apache.commons.io.output;
    019
    020import java.io.IOException;
    021import java.io.OutputStream;
    022
    023import org.apache.commons.io.IOUtils;
    024
    025/**
    026 * Throws an IOException on all attempts to write to the stream.
    027 * <p>
    028 * 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
    029 * {@code null} output stream.
    030 * </p>
    031 *
    032 * @since 1.4
    033 */
    034public class ClosedOutputStream extends OutputStream {
    035
    036    /**
    037     * The singleton instance.
    038     *
    039     * @since 2.12.0
    040     */
    041    public static final ClosedOutputStream INSTANCE = new ClosedOutputStream();
    042
    043    /**
    044     * The singleton instance.
    045     *
    046     * @deprecated Use {@link #INSTANCE}.
    047     */
    048    @Deprecated
    049    public static final ClosedOutputStream CLOSED_OUTPUT_STREAM = INSTANCE;
    050
    051    /**
    052     * Construct a new instance.
    053     */
    054    public ClosedOutputStream() {
    055        // empty
    056    }
    057
    058    /**
    059     * Throws an {@link IOException} to indicate that the stream is closed.
    060     *
    061     * @throws IOException always thrown.
    062     */
    063    @Override
    064    public void flush() throws IOException {
    065        throw new IOException("flush() failed: stream is closed");
    066    }
    067
    068    /**
    069     * Throws an {@link IOException} to indicate that the stream is closed.
    070     *
    071     * @param b   Byte array, never {@code null}.
    072     * @param off The start offset in the byte array.
    073     * @param len The number of bytes to write.
    074     * @throws NullPointerException if the byte array is {@code null}.
    075     * @throws IndexOutOfBoundsException if {@code off} or {@code len} are negative, or if {@code off + len} is greater than {@code b.length}.
    076     * @throws IOException always thrown.
    077     */
    078    @Override
    079    public void write(final byte b[], final int off, final int len) throws IOException {
    080        IOUtils.checkFromIndexSize(b, off, len);
    081        throw new IOException("write(byte[], int, int) failed: stream is closed");
    082    }
    083
    084    /**
    085     * Throws an {@link IOException} to indicate that the stream is closed.
    086     *
    087     * @param b ignored.
    088     * @throws IOException always thrown.
    089     */
    090    @Override
    091    public void write(final int b) throws IOException {
    092        throw new IOException("write(int) failed: stream is closed");
    093    }
    094}