    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
    023import org.apache.commons.io.function.Erase;
    024
    025/**
    026 * Always throws an exception from all {@link OutputStream} methods where {@link IOException} is declared.
    027 * <p>
    028 * This class is mostly useful for testing error handling.
    029 * </p>
    030 *
    031 * @since 2.0
    032 */
    033public class BrokenOutputStream extends OutputStream {
    034
    035    /**
    036     * The singleton instance using a default IOException.
    037     *
    038     * @since 2.12.0
    039     */
    040    public static final BrokenOutputStream INSTANCE = new BrokenOutputStream();
    041
    042    /**
    043     * Supplies the exception that is thrown by all methods of this class.
    044     */
    045    private final Supplier<Throwable> 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     * @deprecated Use {@link #BrokenOutputStream(Throwable)}.
    059     */
    060    @Deprecated
    061    public BrokenOutputStream(final IOException exception) {
    062        this(() -> exception);
    063    }
    064
    065    /**
    066     * Constructs a new stream that always throws the supplied exception.
    067     *
    068     * @param exceptionSupplier a supplier for the IOException or RuntimeException to be thrown.
    069     * @since 2.12.0
    070     */
    071    public BrokenOutputStream(final Supplier<Throwable> exceptionSupplier) {
    072        this.exceptionSupplier = exceptionSupplier;
    073    }
    074
    075    /**
    076     * Constructs a new stream that always throws the given exception.
    077     *
    078     * @param exception the exception to be thrown.
    079     * @since 2.16.0
    080     */
    081    public BrokenOutputStream(final Throwable exception) {
    082        this(() -> exception);
    083    }
    084
    085    /**
    086     * Throws the configured exception.
    087     *
    088     * @throws IOException always throws the exception configured in a constructor.
    089     */
    090    @Override
    091    public void close() throws IOException {
    092        throw rethrow();
    093    }
    094
    095    /**
    096     * Throws the configured exception.
    097     *
    098     * @throws IOException always throws the exception configured in a constructor.
    099     */
    100    @Override
    101    public void flush() throws IOException {
    102        throw rethrow();
    103    }
    104
    105    /**
    106     * Throws the configured exception from its supplier.
    107     *
    108     * @return Throws the configured exception from its supplier.
    109     */
    110    private RuntimeException rethrow() {
    111        return Erase.rethrow(exceptionSupplier.get());
    112    }
    113
    114    /**
    115     * Throws the configured exception.
    116     *
    117     * @param b ignored.
    118     * @throws IOException always throws the exception configured in a constructor.
    119     */
    120    @Override
    121    public void write(final int b) throws IOException {
    122        throw rethrow();
    123    }
    124
    125}