/* * Licensed to the Apache Software Foundation (ASF) under one or more * contributor license agreements. See the NOTICE file distributed with * this work for additional information regarding copyright ownership. * The ASF licenses this file to You under the Apache License, Version 2.0 * (the "License"); you may not use this file except in compliance with * the License. You may obtain a copy of the License at * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. * See the License for the specific language governing permissions and * limitations under the License. */ package org.apache.log4j.helpers; import org.apache.log4j.spi.ErrorHandler; import org.apache.log4j.spi.LoggingEvent; import org.apache.log4j.Logger; import org.apache.log4j.Appender; /** The OnlyOnceErrorHandler implements log4j's default error handling policy which consists of emitting a message for the first error in an appender and ignoring all following errors.

The error message is printed on System.err.

This policy aims at protecting an otherwise working application from being flooded with error messages when logging fails. @author Ceki Gülcü @since 0.9.0 */ public class OnlyOnceErrorHandler implements ErrorHandler { final String WARN_PREFIX = "log4j warning: "; final String ERROR_PREFIX = "log4j error: "; boolean firstTime = true; /** Does not do anything. */ public void setLogger(Logger logger) { } /** No options to activate. */ public void activateOptions() { } /** Prints the message and the stack trace of the exception on System.err. */ public void error(String message, Exception e, int errorCode) { error(message, e, errorCode, null); } /** Prints the message and the stack trace of the exception on System.err. */ public void error(String message, Exception e, int errorCode, LoggingEvent event) { if(firstTime) { LogLog.error(message, e); firstTime = false; } } /** Print a the error message passed as parameter on System.err. */ public void error(String message) { if(firstTime) { LogLog.error(message); firstTime = false; } } /** Does not do anything. */ public void setAppender(Appender appender) { } /** Does not do anything. */ public void setBackupAppender(Appender appender) { } }