1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
|
// Copyright Vespa.ai. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
package com.yahoo.yolean;
import java.io.IOException;
import java.io.UncheckedIOException;
import java.util.Optional;
import java.util.function.Function;
/**
* Helper methods for handling exceptions
*
* @author bratseth
*/
public class Exceptions {
/**
* <p>Returns a user friendly error message string which includes information from all nested exceptions.</p>
*
* <p>The form of this string is
* <code>e.getMessage(): e.getCause().getMessage(): e.getCause().getCause().getMessage()...</code>
* In addition, some heuristics are used to clean up common cases where exception nesting causes bad messages.
*/
public static String toMessageString(Throwable t) {
StringBuilder b = new StringBuilder();
String lastMessage = null;
String message;
for (; t != null; t = t.getCause()) {
message = getMessage(t);
if (message == null) continue;
if (message.isEmpty()) continue;
if (message.equals(lastMessage)) continue;
if (b.length() > 0) {
b.append(": ");
}
b.append(message);
lastMessage = message;
}
return b.toString();
}
/** Returns a useful message from *this* exception, or null if there is nothing useful to return */
private static String getMessage(Throwable t) {
String message = t.getMessage();
if (t.getCause() == null) {
if (message == null) return t.getClass().getSimpleName();
} else {
if (message == null) return null;
if (message.equals(t.getCause().getClass().getName() + ": " + t.getCause().getMessage())) return null;
}
return message;
}
/**
* Returns the first cause or the given throwable that is an instance of {@code clazz}
*/
public static <T extends Throwable> Optional<T> findCause(Throwable t, Class<T> clazz) {
for (; t != null; t = t.getCause()) {
if (clazz.isInstance(t))
return Optional.of(clazz.cast(t));
}
return Optional.empty();
}
/**
* Wraps any IOException thrown from a runnable in an UncheckedIOException.
*/
public static void uncheck(RunnableThrowingIOException runnable) {
try {
runnable.run();
} catch (IOException e) {
throw new UncheckedIOException(e);
}
}
public static void uncheckInterrupted(RunnableThrowingInterruptedException runnable) {
try {
runnable.run();
} catch (InterruptedException e) {
throw new UncheckedInterruptedException(e, false);
}
}
public static void uncheckInterruptedAndRestoreFlag(RunnableThrowingInterruptedException runnable) {
try {
runnable.run();
} catch (InterruptedException e) {
throw new UncheckedInterruptedException(e, true);
}
}
/**
* Wraps any IOException thrown from a runnable in an UncheckedIOException w/message.
*/
public static void uncheck(RunnableThrowingIOException runnable, String format, String... args) {
try {
runnable.run();
} catch (IOException e) {
String message = String.format(format, (Object[]) args);
throw new UncheckedIOException(message, e);
}
}
/** Similar to uncheck(), except an exceptionToIgnore exception is silently ignored. */
public static <T extends IOException> void uncheckAndIgnore(RunnableThrowingIOException runnable, Class<T> exceptionToIgnore) {
try {
runnable.run();
} catch (UncheckedIOException e) {
IOException cause = e.getCause();
if (cause == null) throw e;
try {
cause.getClass().asSubclass(exceptionToIgnore);
} catch (ClassCastException f) {
throw e;
}
// Do nothing - OK
} catch (IOException e) {
try {
e.getClass().asSubclass(exceptionToIgnore);
} catch (ClassCastException f) {
throw new UncheckedIOException(e);
}
// Do nothing - OK
}
}
@FunctionalInterface
public interface RunnableThrowingIOException {
void run() throws IOException;
}
@FunctionalInterface public interface RunnableThrowingInterruptedException { void run() throws InterruptedException; }
/**
* Wraps any IOException thrown from a function in an UncheckedIOException.
*/
public static <T, R> Function<T, R> uncheck(FunctionThrowingIOException<T, R> function) {
return t -> uncheck(() -> function.map(t));
}
@FunctionalInterface public interface FunctionThrowingIOException<T, R> { R map(T t) throws IOException; }
/**
* Wraps any IOException thrown from a supplier in an UncheckedIOException.
*/
public static <T> T uncheck(SupplierThrowingIOException<T> supplier) {
try {
return supplier.get();
} catch (IOException e) {
throw new UncheckedIOException(e);
}
}
/**
* Wraps any IOException thrown from a supplier in an UncheckedIOException w/message.
*/
public static <T> T uncheck(SupplierThrowingIOException<T> supplier, String format, String... args) {
try {
return supplier.get();
} catch (IOException e) {
String message = String.format(format, (Object[]) args);
throw new UncheckedIOException(message, e);
}
}
/** Similar to uncheck(), except null is returned if exceptionToIgnore is thrown. */
public static <R, T extends IOException> R uncheckAndIgnore(SupplierThrowingIOException<R> supplier, Class<T> exceptionToIgnore) {
try {
return supplier.get();
} catch (UncheckedIOException e) {
IOException cause = e.getCause();
if (cause == null) throw e;
try {
cause.getClass().asSubclass(exceptionToIgnore);
} catch (ClassCastException f) {
throw e;
}
return null;
} catch (IOException e) {
try {
e.getClass().asSubclass(exceptionToIgnore);
} catch (ClassCastException f) {
throw new UncheckedIOException(e);
}
return null;
}
}
@FunctionalInterface
public interface SupplierThrowingIOException<T> {
T get() throws IOException;
}
/**
* Allows treating checked exceptions as unchecked.
* Usage:
* throw throwUnchecked(e);
* The reason for the return type is to allow writing throw at the call site
* instead of just calling throwUnchecked. Just calling throwUnchecked
* means that the java compiler won't know that the statement will throw an exception,
* and will therefore complain on things such e.g. missing return value.
*/
public static RuntimeException throwUnchecked(Throwable e) {
throwUncheckedImpl(e);
return new RuntimeException(); // Non-null return value to stop tooling from complaining about potential NPE
}
@SuppressWarnings("unchecked")
private static <T extends Throwable> void throwUncheckedImpl(Throwable t) throws T {
throw (T)t;
}
}
|
