doc/examples/java-log4j2-prog/HelloLog4j2Prog.java

   1 /*
   2  * SPDX-License-Identifier: MIT
   3  *
   4  * Copyright (C) 2022 EfficiOS Inc.
   5  */
   6
   7 import org.apache.logging.log4j.Level;
   8 import org.apache.logging.log4j.LogManager;
   9 import org.apache.logging.log4j.Logger;
  10 import org.apache.logging.log4j.core.config.Configurator;
  11 import org.apache.logging.log4j.core.config.builder.api.AppenderComponentBuilder;
  12 import org.apache.logging.log4j.core.config.builder.api.ConfigurationBuilder;
  13 import org.apache.logging.log4j.core.config.builder.api.ConfigurationBuilderFactory;
  14 import org.apache.logging.log4j.core.config.builder.api.LayoutComponentBuilder;
  15 import org.apache.logging.log4j.core.config.builder.api.RootLoggerComponentBuilder;
  16 import org.apache.logging.log4j.core.config.builder.impl.BuiltConfiguration;
  17
  18 /**
  19  * Example application using the LTTng-UST Java log4j agent.
  20  *
  21  * <p>
  22  * To obtain LTTng trace events, you should run the following sequence of
  23  * commands:
  24  * </p>
  25  *
  26  * <ul>
  27  * <li>$ lttng create</li>
  28  * <li>$ lttng enable-event -l -a</li>
  29  * <li>$ lttng start</li>
  30  * <li>(run this program)</li>
  31  * <li>$ lttng stop</li>
  32  * <li>$ lttng view</li>
  33  * <li>$ lttng destroy</li>
  34  * </ul>
  35  *
  36  */
  37 public class HelloLog4j2Prog {
  38
  39         /**
  40          * Application start
  41          *
  42          * @param args Command-line arguments
  43          */
  44         public static void main(String args[]) {
  45
  46                 ConfigurationBuilder<BuiltConfiguration> builder = ConfigurationBuilderFactory.newConfigurationBuilder();
  47
  48                 /* Layout */
  49                 LayoutComponentBuilder standardLayout = builder.newLayout("PatternLayout");
  50                 standardLayout.addAttribute("pattern", "%d [%t] %-5level: %msg%n%throwable");
  51
  52                 /* Create a console appender */
  53                 AppenderComponentBuilder appenderBuilder = builder.newAppender("Stdout", "Console");
  54                 appenderBuilder.add(standardLayout);
  55                 builder.add(appenderBuilder);
  56
  57                 /* Create an Lttng appender for the LOG4J domain */
  58                 appenderBuilder = builder.newAppender("Lttng1", "Lttng");
  59                 appenderBuilder.addAttribute("domain", "LOG4J");
  60                 builder.add(appenderBuilder);
  61
  62                 /* Create an Lttng appender for the LOG4J2 domain */
  63                 appenderBuilder = builder.newAppender("Lttng2", "Lttng");
  64                 appenderBuilder.addAttribute("domain", "LOG4J2");
  65                 builder.add(appenderBuilder);
  66
  67                 /* Create a root logger with both appenders attached */
  68                 RootLoggerComponentBuilder rootLogger = builder.newRootLogger(Level.DEBUG);
  69                 rootLogger.add(builder.newAppenderRef("Stdout"));
  70                 rootLogger.add(builder.newAppenderRef("Lttng1"));
  71                 rootLogger.add(builder.newAppenderRef("Lttng2"));
  72                 builder.add(rootLogger);
  73
  74                 Configurator.initialize(builder.build());
  75
  76                 Logger logger = LogManager.getLogger(HelloLog4j2Prog.class);
  77
  78                 /* Trigger some tracing events using the Log4j Logger created before. */
  79                 logger.info("Prog config: Hello World, the answer is " + 42);
  80                 logger.info("Prog config: Another info event");
  81                 logger.error("Prog config: An error event");
  82         }
  83 }