org.apache.log4j.varia.FallbackErrorHandler Maven / Gradle / Ivy
/*
* 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.varia;
import java.io.InterruptedIOException;
import java.util.Vector;
import org.apache.log4j.Appender;
import org.apache.log4j.Logger;
import org.apache.log4j.helpers.LogLog;
import org.apache.log4j.spi.ErrorHandler;
import org.apache.log4j.spi.LoggingEvent;
/**
* An ErrorHandler with a secondary appender. This secondary appender takes over if the primary appender fails for
* whatever reason.
*
*
* The error message is printed on System.err, and logged in the new secondary appender.
*
*/
public class FallbackErrorHandler implements ErrorHandler {
Appender backup;
Appender primary;
Vector loggers;
public FallbackErrorHandler() {
// noop
}
/**
* No options to activate.
*/
public void activateOptions() {
// noop
}
/**
* Print a the error message passed as parameter on System.err.
*/
@Override
public void error(final String message) {
// if(firstTime) {
// LogLog.error(message);
// firstTime = false;
// }
}
/**
* Prints the message and the stack trace of the exception on System.err.
*/
@Override
public void error(final String message, final Exception e, final int errorCode) {
error(message, e, errorCode, null);
}
/**
* Prints the message and the stack trace of the exception on System.err.
*/
@Override
public void error(final String message, final Exception e, final int errorCode, final LoggingEvent event) {
if (e instanceof InterruptedIOException) {
Thread.currentThread().interrupt();
}
LogLog.debug("FB: The following error reported: " + message, e);
LogLog.debug("FB: INITIATING FALLBACK PROCEDURE.");
if (loggers != null) {
for (int i = 0; i < loggers.size(); i++) {
final Logger l = (Logger) loggers.elementAt(i);
LogLog.debug("FB: Searching for [" + primary.getName() + "] in logger [" + l.getName() + "].");
LogLog.debug("FB: Replacing [" + primary.getName() + "] by [" + backup.getName() + "] in logger [" + l.getName() + "].");
l.removeAppender(primary);
LogLog.debug("FB: Adding appender [" + backup.getName() + "] to logger " + l.getName());
l.addAppender(backup);
}
}
}
/**
* The appender to which this error handler is attached.
*/
@Override
public void setAppender(final Appender primary) {
LogLog.debug("FB: Setting primary appender to [" + primary.getName() + "].");
this.primary = primary;
}
/**
* Set the backup appender.
*/
@Override
public void setBackupAppender(final Appender backup) {
LogLog.debug("FB: Setting backup appender to [" + backup.getName() + "].");
this.backup = backup;
}
/**
* Adds the logger passed as parameter to the list of loggers that we need to search for in case of appender
* failure.
*/
@Override
public void setLogger(final Logger logger) {
LogLog.debug("FB: Adding logger [" + logger.getName() + "].");
if (loggers == null) {
loggers = new Vector();
}
loggers.addElement(logger);
}
}