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.InputStream;
021import java.util.function.Supplier;
022
023import org.apache.commons.io.function.Erase;
024
025/**
026 * Always throws an exception from all {@link InputStream} 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 BrokenInputStream extends InputStream {
034
035    /**
036     * The singleton instance using a default IOException.
037     *
038     * @since 2.12.0
039     */
040    public static final BrokenInputStream INSTANCE = new BrokenInputStream();
041
042    /**
043     * A supplier for 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 BrokenInputStream() {
051        this(() -> new IOException("Broken input 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 #BrokenInputStream(Throwable)}.
059     */
060    @Deprecated
061    public BrokenInputStream(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 BrokenInputStream(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 BrokenInputStream(final Throwable exception) {
082        this(() -> exception);
083    }
084
085    /**
086     * Throws the configured exception.
087     *
088     * @return nothing.
089     * @throws IOException always throws the exception configured in a constructor.
090     */
091    @Override
092    public int available() throws IOException {
093        throw rethrow();
094    }
095
096    /**
097     * Throws the configured exception.
098     *
099     * @throws IOException always throws the exception configured in a constructor.
100     */
101    @Override
102    public void close() throws IOException {
103        throw rethrow();
104    }
105
106    /**
107     * Gets the Throwable to throw. Package-private for testing.
108     *
109     * @return  the Throwable to throw.
110     */
111    Throwable getThrowable() {
112        return exceptionSupplier.get();
113    }
114
115    /**
116     * Throws the configured exception.
117     *
118     * @return nothing.
119     * @throws IOException always throws the exception configured in a constructor.
120     */
121    @Override
122    public int read() throws IOException {
123        throw rethrow();
124    }
125
126    /**
127     * Throws the configured exception.
128     *
129     * @throws IOException always throws the exception configured in a constructor.
130     */
131    @Override
132    public synchronized void reset() throws IOException {
133        throw rethrow();
134    }
135
136    /**
137     * Throws the configured exception from its supplier.
138     *
139     * @return Throws the configured exception from its supplier.
140     */
141    private RuntimeException rethrow() {
142        return Erase.rethrow(getThrowable());
143    }
144
145    /**
146     * Throws the configured exception.
147     *
148     * @param n ignored.
149     * @return nothing.
150     * @throws IOException always throws the exception configured in a constructor.
151     */
152    @Override
153    public long skip(final long n) throws IOException {
154        throw rethrow();
155    }
156
157}