    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.input;
    018
    019import java.io.IOException;
    020import java.io.Reader;
    021import java.util.function.Supplier;
    022
    023/**
    024 * Always throws an {@link IOException} from all the {@link Reader} methods where the exception is declared.
    025 * <p>
    026 * This class is mostly useful for testing error handling.
    027 * </p>
    028 *
    029 * @since 2.7
    030 */
    031public class BrokenReader extends Reader {
    032
    033    /**
    034     * A singleton instance using a default IOException.
    035     *
    036     * @since 2.12.0
    037     */
    038    public static final BrokenReader INSTANCE = new BrokenReader();
    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 reader that always throws an {@link IOException}.
    047     */
    048    public BrokenReader() {
    049        this(() -> new IOException("Broken reader"));
    050    }
    051
    052    /**
    053     * Creates a new reader that always throws the given exception.
    054     *
    055     * @param exception the exception to be thrown.
    056     */
    057    public BrokenReader(final IOException exception) {
    058        this(() -> exception);
    059    }
    060
    061    /**
    062     * Creates a new reader 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 BrokenReader(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     * @param readAheadLimit ignored
    085     * @throws IOException always thrown
    086     */
    087    @Override
    088    public void mark(final int readAheadLimit) throws IOException {
    089        throw exceptionSupplier.get();
    090    }
    091
    092    /**
    093     * Throws the configured exception.
    094     *
    095     * @param cbuf ignored
    096     * @param off  ignored
    097     * @param len  ignored
    098     * @return nothing
    099     * @throws IOException always thrown
    100     */
    101    @Override
    102    public int read(final char[] cbuf, final int off, final int len) throws IOException {
    103        throw exceptionSupplier.get();
    104    }
    105
    106    /**
    107     * Throws the configured exception.
    108     *
    109     * @return nothing
    110     * @throws IOException always thrown
    111     */
    112    @Override
    113    public boolean ready() throws IOException {
    114        throw exceptionSupplier.get();
    115    }
    116
    117    /**
    118     * Throws the configured exception.
    119     *
    120     * @throws IOException always thrown
    121     */
    122    @Override
    123    public synchronized void reset() throws IOException {
    124        throw exceptionSupplier.get();
    125    }
    126
    127    /**
    128     * Throws the configured exception.
    129     *
    130     * @param n ignored
    131     * @return nothing
    132     * @throws IOException always thrown
    133     */
    134    @Override
    135    public long skip(final long n) throws IOException {
    136        throw exceptionSupplier.get();
    137    }
    138
    139}