1 /*
2 * Licensed to the Apache Software Foundation (ASF) under one or more
3 * contributor license agreements. See the NOTICE file distributed with
4 * this work for additional information regarding copyright ownership.
5 * The ASF licenses this file to You under the Apache License, Version 2.0
6 * (the "License"); you may not use this file except in compliance with
7 * the License. You may obtain a copy of the License at
8 *
9 * https://www.apache.org/licenses/LICENSE-2.0
10 *
11 * Unless required by applicable law or agreed to in writing, software
12 * distributed under the License is distributed on an "AS IS" BASIS,
13 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
14 * See the License for the specific language governing permissions and
15 * limitations under the License.
16 */
17 package org.apache.commons.io.output;
18
19 import java.io.IOException;
20 import java.io.OutputStream;
21 import java.util.function.Function;
22 import java.util.function.Supplier;
23
24 import org.apache.commons.io.function.Erase;
25
26 /**
27 * Always throws an exception from all {@link OutputStream} methods where {@link IOException} is declared.
28 * <p>
29 * This class is mostly useful for testing error handling.
30 * </p>
31 *
32 * @since 2.0
33 */
34 public class BrokenOutputStream extends OutputStream {
35
36 /**
37 * The singleton instance using a default IOException.
38 *
39 * @since 2.12.0
40 */
41 public static final BrokenOutputStream INSTANCE = new BrokenOutputStream();
42
43 /**
44 * Supplies the exception that is thrown by all methods of this class.
45 */
46 private final Function<String, Throwable> exceptionFunction;
47
48 /**
49 * Constructs a new stream that always throws an {@link IOException}.
50 */
51 public BrokenOutputStream() {
52 this(m -> new IOException("Broken output stream: " + m));
53 }
54
55 /**
56 * Constructs a new stream that always throws the supplied exception.
57 * <p>
58 * This class uses the invoked method name as the function input.
59 * </p>
60 *
61 * @param exceptionFunction a supplier for the IOException or RuntimeException to be thrown.
62 * @since 2.19.0
63 */
64 public BrokenOutputStream(final Function<String, Throwable> exceptionFunction) {
65 this.exceptionFunction = exceptionFunction;
66 }
67
68 /**
69 * Constructs a new stream that always throws the given exception.
70 *
71 * @param exception the exception to be thrown.
72 * @deprecated Use {@link #BrokenOutputStream(Throwable)}.
73 */
74 @Deprecated
75 public BrokenOutputStream(final IOException exception) {
76 this(m -> exception);
77 }
78
79 /**
80 * Constructs a new stream that always throws the supplied exception.
81 *
82 * @param exceptionSupplier a supplier for the IOException or RuntimeException to be thrown.
83 * @since 2.12.0
84 * @deprecated Use {@link #BrokenOutputStream(Function)}.
85 */
86 @Deprecated
87 public BrokenOutputStream(final Supplier<Throwable> exceptionSupplier) {
88 this.exceptionFunction = m -> exceptionSupplier.get();
89 }
90
91 /**
92 * Constructs a new stream that always throws the given exception.
93 *
94 * @param exception the exception to be thrown.
95 * @since 2.16.0
96 */
97 public BrokenOutputStream(final Throwable exception) {
98 this(m -> exception);
99 }
100
101 /**
102 * Throws the configured exception.
103 *
104 * @throws IOException always throws the exception configured in a constructor.
105 */
106 @Override
107 public void close() throws IOException {
108 throw rethrow("close()");
109 }
110
111 /**
112 * Throws the configured exception.
113 *
114 * @throws IOException always throws the exception configured in a constructor.
115 */
116 @Override
117 public void flush() throws IOException {
118 throw rethrow("flush()");
119 }
120
121 /**
122 * Throws the configured exception from its supplier.
123 *
124 * @param method The exception function argument.
125 * @return Throws the configured exception from its supplier.
126 */
127 private RuntimeException rethrow(final String method) {
128 return Erase.rethrow(exceptionFunction.apply(method));
129 }
130
131 /**
132 * Throws the configured exception.
133 *
134 * @param b ignored.
135 * @throws IOException always throws the exception configured in a constructor.
136 */
137 @Override
138 public void write(final int b) throws IOException {
139 throw rethrow("write(int)");
140 }
141
142 }