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 * http://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 /** The context where the data is stored. */
91 private final ExceptionContext exceptionContext;
92
93 /**
94 * Instantiates ContextedException without message or cause.
95 * <p>
96 * The context information is stored using a default implementation.
97 */
98 public ContextedException() {
99 exceptionContext = new DefaultExceptionContext();
100 }
101
102 /**
103 * Instantiates ContextedException with message, but without cause.
104 * <p>
105 * The context information is stored using a default implementation.
106 *
107 * @param message the exception message, may be null
108 */
109 public ContextedException(final String message) {
110 super(message);
111 exceptionContext = new DefaultExceptionContext();
112 }
113
114 /**
115 * Instantiates ContextedException with cause and message.
116 * <p>
117 * The context information is stored using a default implementation.
118 *
119 * @param message the exception message, may be null
120 * @param cause the underlying cause of the exception, may be null
121 */
122 public ContextedException(final String message, final Throwable cause) {
123 super(message, cause);
124 exceptionContext = new DefaultExceptionContext();
125 }
126
127 /**
128 * Instantiates ContextedException with cause, message, and ExceptionContext.
129 *
130 * @param message the exception message, may be null
131 * @param cause the underlying cause of the exception, may be null
132 * @param context the context used to store the additional information, null uses default implementation
133 */
134 public ContextedException(final String message, final Throwable cause, ExceptionContext context) {
135 super(message, cause);
136 if (context == null) {
137 context = new DefaultExceptionContext();
138 }
139 exceptionContext = context;
140 }
141
142 /**
143 * Instantiates ContextedException with cause, but without message.
144 * <p>
145 * The context information is stored using a default implementation.
146 *
147 * @param cause the underlying cause of the exception, may be null
148 */
149 public ContextedException(final Throwable cause) {
150 super(cause);
151 exceptionContext = new DefaultExceptionContext();
152 }
153
154 /**
155 * Adds information helpful to a developer in diagnosing and correcting the problem.
156 * For the information to be meaningful, the value passed should have a reasonable
157 * toString() implementation.
158 * Different values can be added with the same label multiple times.
159 * <p>
160 * Note: This exception is only serializable if the object added is serializable.
161 * </p>
162 *
163 * @param label a textual label associated with information, {@code null} not recommended
164 * @param value information needed to understand exception, may be {@code null}
165 * @return {@code this}, for method chaining, not {@code null}
166 */
167 @Override
168 public ContextedException addContextValue(final String label, final Object value) {
169 exceptionContext.addContextValue(label, value);
170 return this;
171 }
172
173 /**
174 * {@inheritDoc}
175 */
176 @Override
177 public List<Pair<String, Object>> getContextEntries() {
178 return this.exceptionContext.getContextEntries();
179 }
180
181 /**
182 * {@inheritDoc}
183 */
184 @Override
185 public Set<String> getContextLabels() {
186 return exceptionContext.getContextLabels();
187 }
188
189 /**
190 * {@inheritDoc}
191 */
192 @Override
193 public List<Object> getContextValues(final String label) {
194 return this.exceptionContext.getContextValues(label);
195 }
196
197 /**
198 * {@inheritDoc}
199 */
200 @Override
201 public Object getFirstContextValue(final String label) {
202 return this.exceptionContext.getFirstContextValue(label);
203 }
204
205 /**
206 * {@inheritDoc}
207 */
208 @Override
209 public String getFormattedExceptionMessage(final String baseMessage) {
210 return exceptionContext.getFormattedExceptionMessage(baseMessage);
211 }
212
213 /**
214 * Provides the message explaining the exception, including the contextual data.
215 *
216 * @see Throwable#getMessage()
217 * @return the message, never null
218 */
219 @Override
220 public String getMessage() {
221 return getFormattedExceptionMessage(super.getMessage());
222 }
223
224 /**
225 * Provides the message explaining the exception without the contextual data.
226 *
227 * @see Throwable#getMessage()
228 * @return the message
229 * @since 3.0.1
230 */
231 public String getRawMessage() {
232 return super.getMessage();
233 }
234
235 /**
236 * Sets information helpful to a developer in diagnosing and correcting the problem.
237 * For the information to be meaningful, the value passed should have a reasonable
238 * toString() implementation.
239 * Any existing values with the same labels are removed before the new one is added.
240 * <p>
241 * Note: This exception is only serializable if the object added as value is serializable.
242 * </p>
243 *
244 * @param label a textual label associated with information, {@code null} not recommended
245 * @param value information needed to understand exception, may be {@code null}
246 * @return {@code this}, for method chaining, not {@code null}
247 */
248 @Override
249 public ContextedException setContextValue(final String label, final Object value) {
250 exceptionContext.setContextValue(label, value);
251 return this;
252 }
253 }