X-Git-Url: http://git.lttng.org/?a=blobdiff_plain;f=liblttng-ust-java-agent%2Fjava%2Flttng-ust-agent-log4j%2Forg%2Flttng%2Fust%2Fagent%2Flog4j%2FLttngLog4jAgent.java;h=157ff3fe879395b88b1d0592805537201457a02c;hb=e494a9cdf17705bddf2169adf3945ed2ae335db9;hp=7dcff9ec4e582721eba2c85675d56671884aa390;hpb=68a1ef7391fb6103eba95fd350ccc61e73855d95;p=lttng-ust.git

diff --git a/liblttng-ust-java-agent/java/lttng-ust-agent-log4j/org/lttng/ust/agent/log4j/LttngLog4jAgent.java b/liblttng-ust-java-agent/java/lttng-ust-agent-log4j/org/lttng/ust/agent/log4j/LttngLog4jAgent.java
index 7dcff9ec..157ff3fe 100644
--- a/liblttng-ust-java-agent/java/lttng-ust-agent-log4j/org/lttng/ust/agent/log4j/LttngLog4jAgent.java
+++ b/liblttng-ust-java-agent/java/lttng-ust-agent-log4j/org/lttng/ust/agent/log4j/LttngLog4jAgent.java
@@ -17,12 +17,15 @@
 
 package org.lttng.ust.agent.log4j;
 
-import java.util.ArrayList;
 import java.util.Collection;
 import java.util.Collections;
+import java.util.Enumeration;
 import java.util.List;
+import java.util.Set;
+import java.util.TreeSet;
 
 import org.apache.log4j.Appender;
+import org.apache.log4j.Category;
 import org.apache.log4j.LogManager;
 import org.apache.log4j.Logger;
 import org.lttng.ust.agent.AbstractLttngAgent;
@@ -50,11 +53,15 @@ class LttngLog4jAgent extends AbstractLttngAgent<LttngLogAppender> {
 
 	@Override
 	public Collection<String> listAvailableEvents() {
-		List<String> ret = new ArrayList<String>();
+		Set<String> ret = new TreeSet<String>();
 
 		@SuppressWarnings("unchecked")
 		List<Logger> loggers = Collections.list(LogManager.getCurrentLoggers());
 		for (Logger logger : loggers) {
+			if (logger == null) {
+				continue;
+			}
+
 			/*
 			 * Check if that logger has at least one LTTng log4j appender
 			 * attached.
@@ -67,14 +74,32 @@ class LttngLog4jAgent extends AbstractLttngAgent<LttngLogAppender> {
 		return ret;
 	}
 
-	private static boolean hasLttngAppenderAttached(Logger logger) {
+	private static boolean hasLttngAppenderAttached(Category logger) {
 		@SuppressWarnings("unchecked")
-		List<Appender> appenders = Collections.list(logger.getAllAppenders());
-		for (Appender appender : appenders) {
-			if (appender instanceof LttngLogAppender) {
-				return true;
+		Enumeration<Appender> appenders = logger.getAllAppenders();
+		if (appenders != null) {
+			for (Appender appender : Collections.list(appenders)) {
+				if (appender instanceof LttngLogAppender) {
+					return true;
+				}
 			}
 		}
+
+		/*
+		 * A parent logger, if any, may be connected to an LTTng handler. In
+		 * this case, we will want to include this child logger in the output,
+		 * since it will be accessible by LTTng.
+		 */
+		Category parent = logger.getParent();
+		if (parent != null) {
+			return hasLttngAppenderAttached(parent);
+		}
+
+		/*
+		 * We have reached the root logger and have not found any LTTng handler,
+		 * this event will not be accessible.
+		 */
 		return false;
 	}
+
 }