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;
021import java.util.function.Supplier;
022
023/**
024 * Broken output stream. This stream always throws an {@link IOException} from
025 * all {@link OutputStream} methods.
026 * <p>
027 * This class is mostly useful for testing error handling in code that uses an
028 * output stream.
029 * </p>
030 *
031 * @since 2.0
032 */
033public class BrokenOutputStream extends OutputStream {
034
035    /**
036     * A singleton instance.
037     *
038     * @since 2.12.0
039     */
040    public static final BrokenOutputStream INSTANCE = new BrokenOutputStream();
041
042    /**
043     * A supplier for the exception that is thrown by all methods of this class.
044     */
045    private final Supplier<IOException> exceptionSupplier;
046
047    /**
048     * Constructs a new stream that always throws an {@link IOException}.
049     */
050    public BrokenOutputStream() {
051        this(() -> new IOException("Broken output stream"));
052    }
053
054    /**
055     * Constructs a new stream that always throws the given exception.
056     *
057     * @param exception the exception to be thrown.
058     */
059    public BrokenOutputStream(final IOException exception) {
060        this(() -> exception);
061    }
062
063    /**
064     * Constructs a new stream that always throws an {@link IOException}.
065     *
066     * @param exceptionSupplier a supplier for the exception to be thrown.
067     * @since 2.12.0
068     */
069    public BrokenOutputStream(final Supplier<IOException> exceptionSupplier) {
070        this.exceptionSupplier = exceptionSupplier;
071    }
072
073    /**
074     * Throws the configured exception.
075     *
076     * @throws IOException always thrown
077     */
078    @Override
079    public void close() throws IOException {
080        throw exceptionSupplier.get();
081    }
082
083    /**
084     * Throws the configured exception.
085     *
086     * @throws IOException always thrown
087     */
088    @Override
089    public void flush() throws IOException {
090        throw exceptionSupplier.get();
091    }
092
093    /**
094     * Throws the configured exception.
095     *
096     * @param b ignored
097     * @throws IOException always thrown
098     */
099    @Override
100    public void write(final int b) throws IOException {
101        throw exceptionSupplier.get();
102    }
103
104}