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.logging.log4j.core.util;
18
19 import java.io.IOException;
20 import java.io.InterruptedIOException;
21 import java.io.LineNumberReader;
22 import java.io.PrintWriter;
23 import java.io.StringReader;
24 import java.io.StringWriter;
25 import java.util.ArrayList;
26 import java.util.List;
27
28 /**
29 * Helps with Throwable objects.
30 */
31 public final class Throwables {
32
33 private Throwables() {
34 }
35
36 /**
37 * Returns the deepest cause of the given {@code throwable}.
38 *
39 * @param throwable the throwable to navigate
40 * @return the deepest throwable or the given throwable
41 */
42 public static Throwable getRootCause(final Throwable throwable) {
43 Throwable cause;
44 Throwable root = throwable;
45 while ((cause = root.getCause()) != null) {
46 root = cause;
47 }
48 return root;
49 }
50
51 /**
52 * Converts a Throwable stack trace into a List of Strings.
53 *
54 * @param throwable the Throwable
55 * @return a List of Strings
56 */
57 public static List<String> toStringList(final Throwable throwable) {
58 final StringWriter sw = new StringWriter();
59 final PrintWriter pw = new PrintWriter(sw);
60 try {
61 throwable.printStackTrace(pw);
62 } catch (final RuntimeException ex) {
63 // Ignore any exceptions.
64 }
65 pw.flush();
66 final List<String> lines = new ArrayList<>();
67 final LineNumberReader reader = new LineNumberReader(new StringReader(sw.toString()));
68 try {
69 String line = reader.readLine();
70 while (line != null) {
71 lines.add(line);
72 line = reader.readLine();
73 }
74 } catch (final IOException ex) {
75 if (ex instanceof InterruptedIOException) {
76 Thread.currentThread().interrupt();
77 }
78 lines.add(ex.toString());
79 } finally {
80 Closer.closeSilently(reader);
81 }
82 return lines;
83 }
84
85 /**
86 * Rethrows a {@link Throwable}.
87 *
88 * @param t the Throwable to throw.
89 * @since 2.1
90 */
91 public static void rethrow(final Throwable t) {
92 Throwables.<RuntimeException>rethrow0(t);
93 }
94
95 @SuppressWarnings("unchecked")
96 private static <T extends Throwable> void rethrow0(final Throwable t) throws T {
97 throw (T) t;
98 }
99 }