import org.apache.log4j.Appender;
import org.apache.log4j.BasicConfigurator;
import org.apache.log4j.Logger;
+import org.apache.log4j.Level;
import org.lttng.ust.agent.log4j.LttngLogAppender;
/**
- * Example application using the LTTng-UST Java JUL agent.
+ * Example application using the LTTng-UST Java log4j agent.
+ *
+ * <p>
+ * To obtain LTTng trace events, you should run the following sequence of
+ * commands:
+ * </p>
+ *
+ * <ul>
+ * <li>$ lttng create</li>
+ * <li>$ lttng enable-event -l -a</li>
+ * <li>$ lttng start</li>
+ * <li>(run this program)</li>
+ * <li>$ lttng stop</li>
+ * <li>$ lttng view</li>
+ * <li>$ lttng destroy</li>
+ * </ul>
*
* @author Alexandre Montplaisir
* @author Christian Babeux
* @param args
* Command-line arguments
* @throws IOException
- * @throws InterruptedException
+ * If the required native libraries cannot be found. You may
+ * have to specify "-Djava.library.path=..." on the "java"
+ * command line.
*/
- public static void main(String args[]) throws IOException, InterruptedException {
+ public static void main(String args[]) throws IOException {
+
+ /*
+ * Set lowest level to make sure all event levels are logged.
+ * Any jar can override the default log4j rootLogger level
+ * and a logger with no explicit level defaults to the non-null
+ * parent level. Events could be ignored if the inherited value
+ * is to low.
+ * e.g BSF -> https://issues.apache.org/jira/browse/BSF-24
+ */
+ HELLO_LOG.setLevel(Level.ALL);
+
/* Start with the default Log4j configuration, which logs to console */
BasicConfigurator.configure();
/*
- * Add a LTTng log appender to the logger, which will also send the
- * logged events to UST.
+ * Instantiate a LTTng log appender and attach it to the logger, which
+ * will now send the logged events to UST.
*/
Appender lttngAppender = new LttngLogAppender();
HELLO_LOG.addAppender(lttngAppender);
*/
// PropertyConfigurator.configure(fileName);
- /*
- * Gives you time to do some lttng commands before any event is hit.
- */
- Thread.sleep(5000);
-
- /* Trigger a tracing event using the Log4j Logger created before. */
+ /* Trigger some tracing events using the Log4j Logger created before. */
HELLO_LOG.info("Hello World, the answer is " + 42);
+ HELLO_LOG.info("Another info event");
+ HELLO_LOG.error("An error event");
- System.out.println("Firing second event in 5 seconds...");
- Thread.sleep(5000);
- HELLO_LOG.info("Hello World delayed...");
-
+ /* Cleanup */
+ HELLO_LOG.removeAppender(lttngAppender);
lttngAppender.close();
}
}