Implement Java agent application context retrieval

[deliverable/lttng-ust.git] / doc / examples / java-jul / ApplicationContextExample.java

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+/*
+ * Copyright (C) 2016 - EfficiOS Inc., Alexandre Montplaisir <alexmonthy@efficios.com>
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to
+ * deal in the Software without restriction, including without limitation the
+ * rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
+ * sell copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
+ * IN THE SOFTWARE.
+ */
+
+import java.io.IOException;
+import java.util.logging.Handler;
+import java.util.logging.Logger;
+
+import org.lttng.ust.agent.context.ContextInfoManager;
+import org.lttng.ust.agent.context.IContextInfoRetriever;
+import org.lttng.ust.agent.jul.LttngLogHandler;
+
+/**
+ * Example program defining a application context retriever, which allows
+ * attaching application-defined contexts to trace events.
+ *
+ * FIXME Use custom context names, and several names/types
+ *
+ * <p>
+ * Usage:
+ * <ul>
+ * <li>$ lttng create</li>
+ * <li>$ lttng enable-event -j -a</li>
+ * <li>$ lttng add-context -j -t '$app.myprovider:mystringcontext'</li>
+ * <li>$ lttng add-context -j -t '$app.myprovider:myshortcontext'</li>
+ * <li>$ lttng start</li>
+ * <li>(run this program)</li>
+ * <li>$ lttng stop</li>
+ * <li>$ lttng view</li>
+ * <li>$ lttng destroy</li>
+ * </ul>
+ * </p>
+ *
+ * The events present in the resulting trace should carry the context
+ * information defined in the example retriever.
+ *
+ * @author Alexandre Montplaisir
+ */
+public class ApplicationContextExample {
+
+       /** Class-wide JUL logger object */
+       private static final Logger LOGGER = Logger.getLogger(ApplicationContextExample.class.getName());
+
+       private static final String RETRIEVER_NAME = "myprovider";
+       private static final String CONTEXT_NAME_STRING = "mystringcontext";
+       private static final String CONTEXT_NAME_SHORT = "myshortcontext";
+
+       private static class ExampleContextInfoRetriever implements IContextInfoRetriever {
+
+               @Override
+               public Object retrieveContextInfo(String key) {
+                       switch (key) {
+                       case CONTEXT_NAME_SHORT:
+                               return (short) 42;
+                       case CONTEXT_NAME_STRING:
+                               return "context-value!";
+                       default:
+                               return null;
+                       }
+               }
+
+       }
+
+       /**
+        * Application start
+        *
+        * @param args
+        *            Command-line arguments
+        * @throws IOException
+        * @throws InterruptedException
+        */
+       public static void main(String args[]) throws IOException, InterruptedException {
+               /* Instantiate and attach a logger object */
+               Handler lttngHandler = new LttngLogHandler();
+               LOGGER.addHandler(lttngHandler);
+
+               /* Instantiate and register the context retriever */
+               IContextInfoRetriever cir = new ExampleContextInfoRetriever();
+               ContextInfoManager.getInstance().registerContextInfoRetriever(RETRIEVER_NAME, cir);
+
+               /*
+                * Make sure you have a LTTng session running with the appropriate
+                * events and contexts enabled! See the class Javadoc.
+                */
+
+               /* Trigger a tracing event using the JUL Logger created before. */
+               LOGGER.info("Log event #1");
+               LOGGER.warning("Log event #2");
+               LOGGER.severe("Log event #3");
+
+               /* Unregister our context retriever, and dispose the log handler */
+               ContextInfoManager.getInstance().unregisterContextInfoRetriever(RETRIEVER_NAME);
+               lttngHandler.close();
+       }
+}