X-Git-Url: http://git.lttng.org./?a=blobdiff_plain;f=doc%2Fexamples%2Fjava-log4j%2FHello.java;h=2f1119c05e346d85d9da45f5650d1d355bf5cf24;hb=b1035e615d2283d13fc7598e64a9e82f068a37c8;hp=c0393392e96bea7a9d402d088b441391fdd3bdb3;hpb=5bfeaeca7fd73ebdc5aa9f555213055272daab29;p=lttng-ust.git

diff --git a/doc/examples/java-log4j/Hello.java b/doc/examples/java-log4j/Hello.java
index c0393392..2f1119c0 100644
--- a/doc/examples/java-log4j/Hello.java
+++ b/doc/examples/java-log4j/Hello.java
@@ -1,4 +1,5 @@
 /*
+ * Copyright (C) 2015 - EfficiOS Inc., Alexandre Montplaisir <alexmonthy@efficios.com>
  * Copyright (C) 2014 - Christian Babeux <christian.babeux@efficios.com>
  *
  * Permission is hereby granted, free of charge, to any person obtaining a copy
@@ -20,47 +21,84 @@
  * IN THE SOFTWARE.
  */
 
+import java.io.IOException;
+
+import org.apache.log4j.Appender;
 import org.apache.log4j.BasicConfigurator;
 import org.apache.log4j.Logger;
-import org.lttng.ust.agent.LTTngAgent;
+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
  */
 public class Hello {
 
-	/* Of course :) */
-	private static final int answer = 42;
-
-	static Logger helloLog = Logger.getLogger(Hello.class);
-
-	private static LTTngAgent lttngAgent;
+	private static final Logger HELLO_LOG = Logger.getLogger(Hello.class);
 
 	/**
 	 * Application start
 	 *
 	 * @param args
 	 *            Command-line arguments
-	 * @throws Exception
+	 * @throws IOException
+	 *             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 Exception {
+	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();
-		lttngAgent = LTTngAgent.getLTTngAgent();
 
 		/*
-		 * Gives you time to do some lttng commands before any event is hit.
+		 * Instantiate a LTTng log appender and attach it to the logger, which
+		 * will now send the logged events to UST.
 		 */
-		Thread.sleep(5000);
+		Appender lttngAppender = new LttngLogAppender();
+		HELLO_LOG.addAppender(lttngAppender);
 
-		/* Trigger a tracing event using the JUL Logger created before. */
-		helloLog.info("Hello World, the answer is " + answer);
+		/*
+		 * Here we've set up the appender programmatically, but it could also be
+		 * defined at runtime, by reading a configuration file for example:
+		 */
+		// PropertyConfigurator.configure(fileName);
 
-		System.out.println("Firing hello delay in 5 seconds...");
-		Thread.sleep(5000);
-		helloLog.info("Hello World delayed...");
+		/* 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");
 
-		lttngAgent.dispose();
+		/* Cleanup */
+		HELLO_LOG.removeAppender(lttngAppender);
+		lttngAppender.close();
 	}
 }