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