1 /**
2 * This file Copyright (c) 2009-2015 Magnolia International
3 * Ltd. (http://www.magnolia-cms.com). All rights reserved.
4 *
5 *
6 * This file is dual-licensed under both the Magnolia
7 * Network Agreement and the GNU General Public License.
8 * You may elect to use one or the other of these licenses.
9 *
10 * This file is distributed in the hope that it will be
11 * useful, but AS-IS and WITHOUT ANY WARRANTY; without even the
12 * implied warranty of MERCHANTABILITY or FITNESS FOR A
13 * PARTICULAR PURPOSE, TITLE, or NONINFRINGEMENT.
14 * Redistribution, except as permitted by whichever of the GPL
15 * or MNA you select, is prohibited.
16 *
17 * 1. For the GPL license (GPL), you can redistribute and/or
18 * modify this file under the terms of the GNU General
19 * Public License, Version 3, as published by the Free Software
20 * Foundation. You should have received a copy of the GNU
21 * General Public License, Version 3 along with this program;
22 * if not, write to the Free Software Foundation, Inc., 51
23 * Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
24 *
25 * 2. For the Magnolia Network Agreement (MNA), this file
26 * and the accompanying materials are made available under the
27 * terms of the MNA which accompanies this distribution, and
28 * is available at http://www.magnolia-cms.com/mna.html
29 *
30 * Any modifications to this file must keep this entire header
31 * intact.
32 *
33 */
34 package info.magnolia.cms.util;
35
36 import org.apache.commons.lang3.StringUtils;
37
38 /**
39 * Util to handle exceptions.
40 */
41 public class ExceptionUtil {
42
43 /**
44 * Given a RuntimeException, this method will:
45 * - throw its cause exception, if the cause exception is an instance of the type of the unwrapIf parameter
46 * - throw its cause exception, if the cause exception is a RuntimeException
47 * - throw the given RuntimeException otherwise.
48 */
49 public static <E extends Throwable> void unwrapIf(RuntimeException e, Class<E> unwrapIf) throws E {
50 final Throwable wrapped = e.getCause();
51 if (unwrapIf != null && unwrapIf.isInstance(wrapped)) {
52 throw (E) wrapped;
53 } else if (wrapped != null && wrapped instanceof RuntimeException) {
54 throw (RuntimeException) wrapped;
55 } else {
56 throw e;
57 }
58 }
59
60 /**
61 * This method helps palliating the absence of multi-catch (introduced in Java 7) - catch the lower common
62 * denominator exception and let this method do the rest - <strong>Use with great care!</strong>.
63 * <strong>Warning:</strong> this method can be abused, and would let one throw undeclared exceptions, which would
64 * in turn produce unexpected and undesirable effects on calling code. Just resist the urge to use this outside
65 * "multi-catch" scenarios.
66 */
67 public static void rethrow(Throwable e, Class<? extends Throwable>... allowedExceptions) {
68 if (RuntimeException.class.isInstance(e)) {
69 throw (RuntimeException) e;
70 }
71 for (Class<? extends Throwable> allowedException : allowedExceptions) {
72 if (allowedException.isInstance(e)) {
73 sneakyThrow(e);
74 }
75 }
76 throw new Error("Caught the following exception, which was not allowed: ", e);
77 }
78
79 /**
80 * Highly inspired by Lombok and the JavaPuzzlers, this method will let you throw a checked exception without declaring it.
81 * Use with GREAT care.
82 */
83 private static void sneakyThrow(Throwable t) {
84 ExceptionUtil.<RuntimeException>sneakyThrow_(t);
85 }
86
87 @SuppressWarnings("unchecked")
88 private static <T extends Throwable> void sneakyThrow_(Throwable t) throws T {
89 throw (T) t;
90 }
91
92 /**
93 * Returns true if the given exception or any of the nested cause exceptions is an instance of the <tt>suspectedCause</tt> exception argument, or a subclass thereof.
94 * This is equivalent to ExceptionUtils.indexOfThrowable(e, javax.jcr.AccessDeniedException.class) >= 0, only more readable, and possibly more performant.
95 */
96 public static boolean wasCausedBy(Throwable e, Class<? extends Throwable> suspectedCause) {
97 if (e != null && suspectedCause.isAssignableFrom(e.getClass())) {
98 return true;
99 } else if (e == null) {
100 return false;
101 } else {
102 return wasCausedBy(e.getCause(), suspectedCause);
103 }
104 }
105
106 /**
107 * Translates an exception class name to an english-readable idiom. Example: an instance of AccessDeniedException will be returned as "Access denied".
108 */
109 public static String classNameToWords(Exception e) {
110 return classNameToWords((Throwable) e);
111 }
112
113 public static String classNameToWords(Throwable e) {
114 return StringUtils.capitalize(StringUtils.removeEnd(e.getClass().getSimpleName(), "Exception").replaceAll("[A-Z]", " $0").toLowerCase().trim());
115 }
116
117 /**
118 * Translates an exception class name to an english-readable idiom, along with the exception's message.
119 * Example: an instance of AccessDeniedException("/foo/bar") will be returned as "Access denied: /foo/bar".
120 */
121 public static String exceptionToWords(Exception e) {
122 return exceptionToWords((Throwable) e);
123 }
124
125 public static String exceptionToWords(Throwable e) {
126 if (e.getMessage() != null) {
127 return classNameToWords(e) + ": " + e.getMessage();
128 } else {
129 return classNameToWords(e);
130 }
131 }
132 }