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
18 package org.apache.log4j.helpers;
19
20 import org.apache.log4j.spi.ErrorHandler;
21 import org.apache.log4j.spi.LoggingEvent;
22 import org.apache.log4j.Logger;
23 import org.apache.log4j.Appender;
24
25 import java.io.InterruptedIOException;
26
27 /**
28
29 The <code>OnlyOnceErrorHandler</code> implements log4j's default
30 error handling policy which consists of emitting a message for the
31 first error in an appender and ignoring all following errors.
32
33 <p>The error message is printed on <code>System.err</code>.
34
35 <p>This policy aims at protecting an otherwise working application
36 from being flooded with error messages when logging fails.
37
38 @author Ceki Gülcü
39 @since 0.9.0 */
40 public class OnlyOnceErrorHandler implements ErrorHandler {
41
42
43 final String WARN_PREFIX = "log4j warning: ";
44 final String ERROR_PREFIX = "log4j error: ";
45
46 boolean firstTime = true;
47
48
49 /**
50 Does not do anything.
51 */
52 public
53 void setLogger(Logger logger) {
54 }
55
56
57 /**
58 No options to activate.
59 */
60 public
61 void activateOptions() {
62 }
63
64
65 /**
66 Prints the message and the stack trace of the exception on
67 <code>System.err</code>. */
68 public
69 void error(String message, Exception e, int errorCode) {
70 error(message, e, errorCode, null);
71 }
72
73 /**
74 Prints the message and the stack trace of the exception on
75 <code>System.err</code>.
76 */
77 public
78 void error(String message, Exception e, int errorCode, LoggingEvent event) {
79 if (e instanceof InterruptedIOException || e instanceof InterruptedException) {
80 Thread.currentThread().interrupt();
81 }
82 if(firstTime) {
83 LogLog.error(message, e);
84 firstTime = false;
85 }
86 }
87
88
89 /**
90 Print a the error message passed as parameter on
91 <code>System.err</code>.
92 */
93 public
94 void error(String message) {
95 if(firstTime) {
96 LogLog.error(message);
97 firstTime = false;
98 }
99 }
100
101 /**
102 Does not do anything.
103 */
104 public
105 void setAppender(Appender appender) {
106 }
107
108 /**
109 Does not do anything.
110 */
111 public
112 void setBackupAppender(Appender appender) {
113 }
114 }