Terrier Core

Terrier always reconfigures log4j and thus breaks a log4j configuration that may have been set up by the environment in which Terrier is run. One way of avoiding this is try figuring out if log4j already was configured and if so not try to configure it again. A simple check would be to test if any appenders for the root logger are configured already:

{code}
//setup log4j
if (!Logger.getRootLogger().getAllAppenders().hasMoreElements()) {
if (new File(LOG4J_CONFIG).exists())
{
DOMConfigurator.configure(LOG4J_CONFIG);
}
else
{
//slightly ugly hack: record a good default configuration as a String in this class, and load that
//emulating DOMConfigurator.configure(Reader)
//see http://svn.apache.org/viewvc/logging/log4j/branches/v1_2-branch/src/java/org/apache/log4j/xml/DOMConfigurator.java?revision=311462&view=markup
new DOMConfigurator().doConfigure(new StringReader(DEFAULT_LOG4J_CONFIG), org.apache.log4j.LogManager.getLoggerRepository());
}
}
{code}

A more sophisticated example of how to check this can be found here: http://svn.apache.org/viewvc/db/ojb/branches/OJB_1_0_RELEASE/src/java/org/apache/ojb/broker/util/logging/Log4jLoggerImpl.java?view=markup in the method isLog4JConfigured() (Apache License obviously).