001/* 002 * Licensed to the Apache Software Foundation (ASF) under one or more 003 * contributor license agreements. See the NOTICE file distributed with 004 * this work for additional information regarding copyright ownership. 005 * The ASF licenses this file to You under the Apache License, Version 2.0 006 * (the "License"); you may not use this file except in compliance with 007 * the License. You may obtain a copy of the License at 008 * 009 * http://www.apache.org/licenses/LICENSE-2.0 010 * 011 * Unless required by applicable law or agreed to in writing, software 012 * distributed under the License is distributed on an "AS IS" BASIS, 013 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 014 * See the License for the specific language governing permissions and 015 * limitations under the License. 016 */ 017 018package org.apache.log4j.helpers; 019 020import org.apache.log4j.spi.ErrorHandler; 021import org.apache.log4j.spi.LoggingEvent; 022import org.apache.log4j.Logger; 023import org.apache.log4j.Appender; 024 025import java.io.InterruptedIOException; 026 027/** 028 029 The <code>OnlyOnceErrorHandler</code> implements log4j's default 030 error handling policy which consists of emitting a message for the 031 first error in an appender and ignoring all following errors. 032 033 <p>The error message is printed on <code>System.err</code>. 034 035 <p>This policy aims at protecting an otherwise working application 036 from being flooded with error messages when logging fails. 037 038 @author Ceki Gülcü 039 @since 0.9.0 */ 040public class OnlyOnceErrorHandler implements ErrorHandler { 041 042 043 final String WARN_PREFIX = "log4j warning: "; 044 final String ERROR_PREFIX = "log4j error: "; 045 046 boolean firstTime = true; 047 048 049 /** 050 Does not do anything. 051 */ 052 public 053 void setLogger(Logger logger) { 054 } 055 056 057 /** 058 No options to activate. 059 */ 060 public 061 void activateOptions() { 062 } 063 064 065 /** 066 Prints the message and the stack trace of the exception on 067 <code>System.err</code>. */ 068 public 069 void error(String message, Exception e, int errorCode) { 070 error(message, e, errorCode, null); 071 } 072 073 /** 074 Prints the message and the stack trace of the exception on 075 <code>System.err</code>. 076 */ 077 public 078 void error(String message, Exception e, int errorCode, LoggingEvent event) { 079 if (e instanceof InterruptedIOException || e instanceof InterruptedException) { 080 Thread.currentThread().interrupt(); 081 } 082 if(firstTime) { 083 LogLog.error(message, e); 084 firstTime = false; 085 } 086 } 087 088 089 /** 090 Print a the error message passed as parameter on 091 <code>System.err</code>. 092 */ 093 public 094 void error(String message) { 095 if(firstTime) { 096 LogLog.error(message); 097 firstTime = false; 098 } 099 } 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}