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.lang3.exception;
18
19 import java.util.List;
20 import java.util.Set;
21
22 import org.apache.commons.lang3.tuple.Pair;
23
24 /**
25 * An exception that provides an easy and safe way to add contextual information.
26 * <p>
27 * An exception trace itself is often insufficient to provide rapid diagnosis of the issue.
28 * Frequently what is needed is a select few pieces of local contextual data.
29 * Providing this data is tricky however, due to concerns over formatting and nulls.
30 * </p><p>
31 * The contexted exception approach allows the exception to be created together with a
32 * list of context label-value pairs. This additional information is automatically included in
33 * the message and printed stack trace.
34 * </p><p>
35 * An unchecked version of this exception is provided by ContextedRuntimeException.
36 * </p>
37 * <p>
38 * To use this class write code as follows:
39 * </p>
40 * <pre>
41 * try {
42 * ...
43 * } catch (Exception e) {
44 * throw new ContextedException("Error posting account transaction", e)
45 * .addContextValue("Account Number", accountNumber)
46 * .addContextValue("Amount Posted", amountPosted)
47 * .addContextValue("Previous Balance", previousBalance);
48 * }
49 * }
50 * </pre>
51 * <p>
52 * or improve diagnose data at a higher level:
53 * </p>
54 * <pre>
55 * try {
56 * ...
57 * } catch (ContextedException e) {
58 * throw e.setContextValue("Transaction Id", transactionId);
59 * } catch (Exception e) {
60 * if (e instanceof ExceptionContext) {
61 * e.setContextValue("Transaction Id", transactionId);
62 * }
63 * throw e;
64 * }
65 * }
66 * </pre>
67 * <p>
68 * The output in a printStacktrace() (which often is written to a log) would look something like the following:
69 * </p>
70 * <pre>
71 * org.apache.commons.lang3.exception.ContextedException: java.lang.Exception: Error posting account transaction
72 * Exception Context:
73 * [1:Account Number=null]
74 * [2:Amount Posted=100.00]
75 * [3:Previous Balance=-2.17]
76 * [4:Transaction Id=94ef1d15-d443-46c4-822b-637f26244899]
77 *
78 * ---------------------------------
79 * at org.apache.commons.lang3.exception.ContextedExceptionTest.testAddValue(ContextedExceptionTest.java:88)
80 * ..... (rest of trace)
81 * </pre>
82 *
83 * @see ContextedRuntimeException
84 * @since 3.0
85 */
86 public class ContextedException extends Exception implements ExceptionContext {
87
88 /** The serialization version. */
89 private static final long serialVersionUID = 20110706L;
90
91 /** The context where the data is stored. */
92 private final ExceptionContext exceptionContext;
93
94 /**
95 * Instantiates ContextedException without message or cause.
96 * <p>
97 * The context information is stored using a default implementation.
98 */
99 public ContextedException() {
100 exceptionContext = new DefaultExceptionContext();
101 }
102
103 /**
104 * Instantiates ContextedException with message, but without cause.
105 * <p>
106 * The context information is stored using a default implementation.
107 *
108 * @param message the exception message, may be null
109 */
110 public ContextedException(final String message) {
111 super(message);
112 exceptionContext = new DefaultExceptionContext();
113 }
114
115 /**
116 * Instantiates ContextedException with cause and message.
117 * <p>
118 * The context information is stored using a default implementation.
119 *
120 * @param message the exception message, may be null
121 * @param cause the underlying cause of the exception, may be null
122 */
123 public ContextedException(final String message, final Throwable cause) {
124 super(message, cause);
125 exceptionContext = new DefaultExceptionContext();
126 }
127
128 /**
129 * Instantiates ContextedException with cause, message, and ExceptionContext.
130 *
131 * @param message the exception message, may be null
132 * @param cause the underlying cause of the exception, may be null
133 * @param context the context used to store the additional information, null uses default implementation
134 */
135 public ContextedException(final String message, final Throwable cause, ExceptionContext context) {
136 super(message, cause);
137 if (context == null) {
138 context = new DefaultExceptionContext();
139 }
140 exceptionContext = context;
141 }
142
143 /**
144 * Instantiates ContextedException with cause, but without message.
145 * <p>
146 * The context information is stored using a default implementation.
147 *
148 * @param cause the underlying cause of the exception, may be null
149 */
150 public ContextedException(final Throwable cause) {
151 super(cause);
152 exceptionContext = new DefaultExceptionContext();
153 }
154
155 /**
156 * Adds information helpful to a developer in diagnosing and correcting the problem.
157 * For the information to be meaningful, the value passed should have a reasonable
158 * toString() implementation.
159 * Different values can be added with the same label multiple times.
160 * <p>
161 * Note: This exception is only serializable if the object added is serializable.
162 * </p>
163 *
164 * @param label a textual label associated with information, {@code null} not recommended
165 * @param value information needed to understand exception, may be {@code null}
166 * @return {@code this}, for method chaining, not {@code null}
167 */
168 @Override
169 public ContextedException addContextValue(final String label, final Object value) {
170 exceptionContext.addContextValue(label, value);
171 return this;
172 }
173
174 /**
175 * {@inheritDoc}
176 */
177 @Override
178 public List<Pair<String, Object>> getContextEntries() {
179 return this.exceptionContext.getContextEntries();
180 }
181
182 /**
183 * {@inheritDoc}
184 */
185 @Override
186 public Set<String> getContextLabels() {
187 return exceptionContext.getContextLabels();
188 }
189
190 /**
191 * {@inheritDoc}
192 */
193 @Override
194 public List<Object> getContextValues(final String label) {
195 return this.exceptionContext.getContextValues(label);
196 }
197
198 /**
199 * {@inheritDoc}
200 */
201 @Override
202 public Object getFirstContextValue(final String label) {
203 return this.exceptionContext.getFirstContextValue(label);
204 }
205
206 /**
207 * {@inheritDoc}
208 */
209 @Override
210 public String getFormattedExceptionMessage(final String baseMessage) {
211 return exceptionContext.getFormattedExceptionMessage(baseMessage);
212 }
213
214 /**
215 * Provides the message explaining the exception, including the contextual data.
216 *
217 * @see Throwable#getMessage()
218 * @return the message, never null
219 */
220 @Override
221 public String getMessage() {
222 return getFormattedExceptionMessage(super.getMessage());
223 }
224
225 /**
226 * Provides the message explaining the exception without the contextual data.
227 *
228 * @see Throwable#getMessage()
229 * @return the message
230 * @since 3.0.1
231 */
232 public String getRawMessage() {
233 return super.getMessage();
234 }
235
236 /**
237 * Sets information helpful to a developer in diagnosing and correcting the problem.
238 * For the information to be meaningful, the value passed should have a reasonable
239 * toString() implementation.
240 * Any existing values with the same labels are removed before the new one is added.
241 * <p>
242 * Note: This exception is only serializable if the object added as value is serializable.
243 * </p>
244 *
245 * @param label a textual label associated with information, {@code null} not recommended
246 * @param value information needed to understand exception, may be {@code null}
247 * @return {@code this}, for method chaining, not {@code null}
248 */
249 @Override
250 public ContextedException setContextValue(final String label, final Object value) {
251 exceptionContext.setContextValue(label, value);
252 return this;
253 }
254 }