Akka/Scala example source code file (LoggingAdapterTest.java)

This example Akka source code file (LoggingAdapterTest.java) is included in my "Source Code Warehouse" project. The intent of this project is to help you more easily find Akka and Scala source code examples by using tags.

All credit for the original source code belongs to akka.io; I'm just trying to make examples easier to find. (For my Scala work, see my Scala examples and tutorials.)

Akka tags/keywords

a, actor, akka, args, concurrent, error, log, logjavatestkit, map, mdc, string, test, testing, the, time

The LoggingAdapterTest.java Akka example source code

package akka.event;

import akka.actor.ActorRef;
import akka.actor.ActorSystem;
import akka.actor.Props;
import akka.testkit.JavaTestKit;
import akka.event.Logging.Error;
import akka.event.ActorWithMDC.Log;
import static akka.event.Logging.*;

import com.typesafe.config.Config;
import com.typesafe.config.ConfigFactory;
import org.junit.Test;
import scala.concurrent.duration.Duration;

import java.util.*;
import java.util.concurrent.TimeUnit;

import static org.junit.Assert.assertEquals;
import static org.junit.Assert.assertNotNull;
import static org.junit.Assert.assertSame;


public class LoggingAdapterTest {

    private static final Config config = ConfigFactory.parseString(
            "akka.loglevel = DEBUG\n" +
            "akka.actor.serialize-messages = off"
    );

    @Test
    public void mustFormatMessage() {
        final ActorSystem system = ActorSystem.create("test-system", config);
        final LoggingAdapter log = Logging.getLogger(system, this);
        new LogJavaTestKit(system) {{
            system.eventStream().subscribe(getRef(), LogEvent.class);
            log.error("One arg message: {}", "the arg");
            expectLog(ErrorLevel(), "One arg message: the arg");

            Throwable cause = new IllegalStateException("This state is illegal");
            log.error(cause, "Two args message: {}, {}", "an arg", "another arg");
            expectLog(ErrorLevel(), "Two args message: an arg, another arg", cause);

            int[] primitiveArgs = {10, 20, 30};
            log.warning("Args as array of primitives: {}, {}, {}", primitiveArgs);
            expectLog(WarningLevel(), "Args as array of primitives: 10, 20, 30");

            Date now = new Date();
            UUID uuid = UUID.randomUUID();
            Object[] objArgs = {"A String", now, uuid};
            log.info("Args as array of objects: {}, {}, {}", objArgs);
            expectLog(InfoLevel(), "Args as array of objects: A String, " + now.toString() + ", " + uuid.toString());

            log.debug("Four args message: {}, {}, {}, {}", 1, 2, 3, 4);
            expectLog(DebugLevel(), "Four args message: 1, 2, 3, 4");

        }};
    }

    @Test
    public void mustCallMdcForEveryLog() throws Exception {
        final ActorSystem system = ActorSystem.create("test-system", config);
        new LogJavaTestKit(system) {{
            system.eventStream().subscribe(getRef(), LogEvent.class);
            ActorRef ref = system.actorOf(Props.create(ActorWithMDC.class));

            ref.tell(new Log(ErrorLevel(), "An Error"), system.deadLetters());
            expectLog(ErrorLevel(), "An Error", "Map(messageLength -> 8)");
            ref.tell(new Log(WarningLevel(), "A Warning"), system.deadLetters());
            expectLog(WarningLevel(), "A Warning", "Map(messageLength -> 9)");
            ref.tell(new Log(InfoLevel(), "Some Info"), system.deadLetters());
            expectLog(InfoLevel(), "Some Info", "Map(messageLength -> 9)");
            ref.tell(new Log(DebugLevel(), "No MDC for 4th call"), system.deadLetters());
            expectLog(DebugLevel(), "No MDC for 4th call");
            ref.tell(new Log(Logging.DebugLevel(), "And now yes, a debug with MDC"), system.deadLetters());
            expectLog(DebugLevel(), "And now yes, a debug with MDC", "Map(messageLength -> 29)");
        }};
    }

    @Test
    public void mustSupportMdcNull() throws Exception {
        final ActorSystem system = ActorSystem.create("test-system", config);
        new LogJavaTestKit(system) {{
            system.eventStream().subscribe(getRef(), LogEvent.class);
            ActorRef ref = system.actorOf(Props.create(ActorWithMDC.class));

            ref.tell(new Log(InfoLevel(), "Null MDC"), system.deadLetters());
            expectLog(InfoLevel(), "Null MDC", "Map()");
        }};
    }

    /*
     * #3671: Let the application specify custom MDC values
     * Java backward compatibility check
     */
    @Test
    public void mustBeAbleToCreateLogEventsWithOldConstructor() throws Exception {
        assertNotNull(new Error(new Exception(), "logSource", this.getClass(), "The message"));
        assertNotNull(new Error("logSource", this.getClass(), "The message"));
        assertNotNull(new Warning("logSource", this.getClass(), "The message"));
        assertNotNull(new Info("logSource", this.getClass(), "The message"));
        assertNotNull(new Debug("logSource", this.getClass(), "The message"));
    }

    private static class LogJavaTestKit extends JavaTestKit {

        private static final String emptyMDC = "Map()";

        public LogJavaTestKit(ActorSystem system) {
            super(system);
        }

        void expectLog(Object level, String message) {
            expectLog(level, message, null, emptyMDC);
        }

        void expectLog(Object level, String message, Throwable cause) {
            expectLog(level, message, cause, emptyMDC);
        }

        void expectLog(Object level, String message, String mdc) {
            expectLog(level, message, null, mdc);
        }

        void expectLog(final Object level, final String message, final Throwable cause, final String mdc) {
            new ExpectMsg<Void>(Duration.create(3, TimeUnit.SECONDS), "LogEvent") {
                protected Void match(Object event) {
                    LogEvent log = (LogEvent) event;
                    assertEquals(message, log.message());
                    assertEquals(level, log.level());
                    assertEquals(mdc, log.mdc().toString());
                    if(cause != null) {
                        Error error = (Error) log;
                        assertSame(cause, error.cause());
                    }
                    return null;
                }
            };
        }
    }
}