An OSGi Activator can allow simple way for reconfiguration of log4j.properties without restarting the JVM.

• Key: DIRSERVER-611
• Type: Improvement
• Status: Closed
• Resolution: Fixed
• Priority: Major
• Assignee: Enrique Rodriguez
• Reporter: John Conlon
• Fix Version/s: 1.5.0

Description

Runtime changes to the log4j.properties file require reconfiguration of the logging infrastructure.

Adding an the attached Activator to an OSGi bundle that exports LOG4J and SLF4J packages a bundle can offer LOG4J and SLF4J packages to other bundles and offer a solution for reconfiguration of the logging infrastructure without restarting the JVM.

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import java.io.FileNotFoundException;
import java.net.MalformedURLException;
import java.net.URL;

import org.apache.log4j.LogManager;
import org.apache.log4j.PropertyConfigurator;
import org.osgi.framework.BundleActivator;
import org.osgi.framework.BundleContext;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

public class Activator implements BundleActivator
{
  private static final String LOG_PROPERTIES_LOCATION =
   "log4j.configuration";

  private Logger log = null;

  public void start(BundleContext bundleContext) throws Exception
  {
                try
                {
                        resetLog4j(bundleContext);
                }
                catch (Exception e)
                {
                        //e.printStackTrace();
                }
                log = LoggerFactory.getLogger(Activator.class);
                log.debug("Reset log configuration.");
  }

  public void stop(BundleContext arg0) throws Exception {}

  /**
   * @return url of the log4j.properties configuration file
   *
   * @throws MalformedURLException
   *
   */
  private URL getLoggingProperty(BundleContext bundleContext)
                        throws MalformedURLException
  {
                final String logPropertiesLocation = bundleContext
                                .getProperty(LOG_PROPERTIES_LOCATION);
                return new URL(logPropertiesLocation);
  }

  /**
   * Reset the log4j configuration.
   * @param bundleContext
   * @throws MalformedURLException
   * @throws FileNotFoundException
   */
  private void resetLog4j(BundleContext bundleContext)
                        throws MalformedURLException,
                              FileNotFoundException
  {
                
    LogManager.resetConfiguration();
    URL log4jprops = getLoggingProperty(bundleContext);

    if (log4jprops != null)
    {
      PropertyConfigurator.configure(log4jprops);
    }
    else
    {
      throw new FileNotFoundException(bundleContext
        .getProperty(LOG_PROPERTIES_LOCATION)
        + " could not be found. "
        + "Please specify add the file and restart the "
        + bundleContext.getBundle().getLocation() + " bundle.");
     }
  }
}