import ch.qos.logback.classic.LoggerContext;
import org.slf4j.ILoggerFactory;
import org.slf4j.LoggerFactory;
import org.slf4j.bridge.SLF4JBridgeHandler;

import javax.servlet.ServletContextEvent;
import javax.servlet.ServletContextListener;

/**
 * Initialise logging at application start up.
 */
public class InitLoggingListener implements ServletContextListener {
	@Override
	public void contextInitialized(ServletContextEvent servletContextEvent) {

		if (System.getProperty("logback.configurationFile") == null) {
			System.setProperty("logback.configurationFile", "myapp.logback.xml");
		}

		// Optionally remove existing handlers attached to j.u.l root logger,
		// including console handler
		SLF4JBridgeHandler.removeHandlersForRootLogger();

		// Bridge java.util.logging into SLF4J, and thus logback
		SLF4JBridgeHandler.install();
	}

	@Override
	public void contextDestroyed(ServletContextEvent servletContextEvent) {
		shutdownLogging();
	}

	/**
	 * Flush and close all logging files
	 */
	private static void shutdownLogging() {

		// We do a logback specific check here, but shouldn't fail if
		// we ever move away from logback to another slf4j logging
		// implementation
		ILoggerFactory loggerFactory = LoggerFactory.getILoggerFactory();
		if (loggerFactory instanceof LoggerContext) {
			LoggerContext context = (LoggerContext) loggerFactory;
			context.stop();
		}
	}
}