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=a548b3c1a329855ad7b2be6937a5a378419fb1b3;hp=5dd846872308eb2d46c1f1dc94175f7b9acf4eec;hpb=d60dfbe48a0ceff16852f46419bcbc405502c61d;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 5dd84687..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
@@ -17,6 +17,17 @@
 
 package org.lttng.ust.agent.log4j;
 
+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;
 
 /**
@@ -40,4 +51,55 @@ class LttngLog4jAgent extends AbstractLttngAgent<LttngLogAppender> {
 		return instance;
 	}
 
+	@Override
+	public Collection<String> listAvailableEvents() {
+		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.
+			 */
+			if (hasLttngAppenderAttached(logger)) {
+				ret.add(logger.getName());
+			}
+		}
+
+		return ret;
+	}
+
+	private static boolean hasLttngAppenderAttached(Category logger) {
+		@SuppressWarnings("unchecked")
+		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;
+	}
+
 }