/*
***************************************************************************************
* Copyright (C) 2006 EsperTech, Inc. All rights reserved. *
* http://www.espertech.com/esper *
* http://www.espertech.com *
* ---------------------------------------------------------------------------------- *
* The software in this package is published under the terms of the GPL license *
* a copy of which has been included with this distribution in the license.txt file. *
***************************************************************************************
*/
/***************************************************************************************
* Attribution Notice
*
* This file is imported from Metrics (https://github.com/codahale/metrics subproject metrics-core).
* Metrics is Copyright (c) 2010-2012 Coda Hale, Yammer.com
* Metrics is Published under Apache Software License 2.0, see LICENSE in root folder.
*
* Thank you for the Metrics developers efforts in making their library available under an Apache license.
* EsperTech incorporates Metrics version 0.2.2 in source code form since Metrics depends on SLF4J
* and this dependency is not possible to introduce for Esper.
* *************************************************************************************
*/
package com.espertech.esper.metrics.codahale_metrics.metrics.util;
import com.espertech.esper.metrics.codahale_metrics.metrics.core.Counter;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
/**
* <p>
* When a thread throws an Exception that was not caught, a DeathRattleExceptionHandler will
* increment a counter signalling a thread has died and print out the name and stack trace of the
* thread.
* This makes it easy to build alerts on unexpected Thread deaths and fine grained used quickens
* debugging in production.
* </p>
* <p>
* You can also set a DeathRattleExceptionHandler as the default exception handler on all threads,
* allowing you to get information on Threads you do not have direct control over.
* </p>
* <p>
* Usage is straightforward:
* </p>
* <pre><code>
* final Counter c = Metrics.newCounter(MyRunnable.class, "thread-deaths");
* Thread.UncaughtExceptionHandler exHandler = new DeathRattleExceptionHandler(c);
* final Thread myThread = new Thread(myRunnable, "MyRunnable");
* myThread.setUncaughtExceptionHandler(exHandler);
* </code></pre>
* <p>
* Setting the global default exception handler should be done first, like so:
* </p>
* <pre><code>
* final Counter c = Metrics.newCounter(MyMainClass.class, "unhandled-thread-deaths");
* Thread.UncaughtExceptionHandler ohNoIDidntKnowAboutThis = new DeathRattleExceptionHandler(c);
* Thread.setDefaultUncaughtExceptionHandler(ohNoIDidntKnowAboutThis);
* </code></pre>
*/
public class DeathRattleExceptionHandler implements Thread.UncaughtExceptionHandler {
private static final Logger log = LoggerFactory.getLogger(DeathRattleExceptionHandler.class);
private final Counter counter;
/**
* Creates a new {@link DeathRattleExceptionHandler} with the given {@link Counter}.
*
* @param counter the {@link Counter} which will be used to record the number of uncaught
* exceptions
*/
public DeathRattleExceptionHandler(Counter counter) {
this.counter = counter;
}
@Override
public void uncaughtException(Thread t, Throwable e) {
counter.inc();
log.error("Uncaught exception on thread " + t + ": " + e.getMessage(), e);
}
}