Remove Listenable interface

After discussion with @maarzt, we agreed that we do not need this
interface. Most things use the event bus. The only exceptions are
LogService and ConsoleService, because we want to maximize performance
of event notification. The Listenable interface has the property that it
cannot be implemented more than once, which in this case could
theoretically be an issue if you want to support notification of
multiple event types. While this would not be a problem initially,
there is also no great need to keep this interface so general.

Author: ctrueden

src/main/java/org/scijava/Listenable.java

@@ -114,16 +114,14 @@ public Logger subLogger(String name, int level) {
 		return rootLogger.subLogger(name, level);
 	}
 
-	// -- Listenable methods --
-
 	@Override
-	public void addListener(final LogListener listener) {
-		rootLogger.addListener(listener);
+	public void addLogListener(final LogListener listener) {
+		rootLogger.addLogListener(listener);
 	}
 
 	@Override
-	public void removeListener(final LogListener listener) {
-		rootLogger.removeListener(listener);
+	public void removeLogListener(final LogListener listener) {
+		rootLogger.removeLogListener(listener);
 	}
 
 	@Override

src/main/java/org/scijava/log/AbstractLogService.java

@@ -76,21 +76,20 @@ public void alwaysLog(final int level, final Object msg, final Throwable t) {
 		messageLogged(new LogMessage(source, level, msg, t));
 	}
 
+	@Override
 	public Logger subLogger(final String name, final int level) {
 		LogSource source = getSource().subSource(name);
 		int actualLevel = source.hasLogLevel() ? source.logLevel() : level;
 		return new DefaultLogger(this, source, actualLevel);
 	}
 
-	// -- Listenable methods --
-
 	@Override
-	public void addListener(final LogListener listener) {
+	public void addLogListener(final LogListener listener) {
 		listeners.add(listener);
 	}
 
 	@Override
-	public void removeListener(final LogListener listener) {
+	public void removeLogListener(final LogListener listener) {
 		listeners.remove(listener);
 	}
 

src/main/java/org/scijava/log/DefaultLogger.java

@@ -37,8 +37,6 @@
 import static org.scijava.log.LogLevel.TRACE;
 import static org.scijava.log.LogLevel.WARN;
 
-import org.scijava.Listenable;
-
 /**
  * Interface for objects which can produce log messages.
  * <p>
@@ -51,7 +49,7 @@
  * @see LogService
  */
 @IgnoreAsCallingClass
-public interface Logger extends Listenable<LogListener, LogMessage> {
+public interface Logger {
 
 	default void debug(final Object msg) {
 		log(DEBUG, msg);
@@ -210,4 +208,13 @@ default Logger subLogger(String name) {
 	 * @param level The log level of the sub logger.
 	 */
 	Logger subLogger(String name, int level);
+
+	/** Adds an item to the list of registered listeners. */
+	void addLogListener(LogListener listener);
+
+	/** Removes an item from the list of registered listeners. */
+	void removeLogListener(LogListener listener);
+
+	/** Broadcasts the given log message to the registered listeners. */
+	void notifyListeners(final LogMessage message);
 }

src/main/java/org/scijava/log/Logger.java

@@ -54,7 +54,7 @@ public class DefaultLoggerTest {
 	public void setup() {
 		logger = new DefaultLogger(message -> {}, LogSource.newRoot(), LogLevel.INFO);
 		listener = new TestLogListener();
-		logger.addListener(listener);
+		logger.addLogListener(listener);
 	}
 
 	@Test
@@ -95,7 +95,7 @@ public void testLogForwarding() {
 		listener.clear();
 		Logger sub = logger.subLogger("xyz");
 		TestLogListener subListener = new TestLogListener();
-		sub.addListener(subListener);
+		sub.addLogListener(subListener);
 
 		sub.error("Hello World!");
 		logger.error("Goodbye!");

src/test/java/org/scijava/log/DefaultLoggerTest.java

@@ -192,7 +192,7 @@ public void testListener() {
 		String msg1 = "Hello World!";
 		String msg2 = "foo bar";
 		// process
-		logService.addListener(listener);
+		logService.addLogListener(listener);
 		logService.error(msg1);
 		logService.subLogger("xyz").debug(msg2);
 		// test

src/test/java/org/scijava/log/LogServiceTest.java

@@ -60,7 +60,7 @@ public void testInjection() throws InterruptedException, ExecutionException {
 		final Context context = new Context(CommandService.class);
 		final CommandService commandService = context.service(CommandService.class);
 		final TestLogListener listener = new TestLogListener();
-		context.service(LogService.class).addListener(listener);
+		context.service(LogService.class).addLogListener(listener);
 
 		commandService.run(CommandWithLogger.class, true).get();
 		assertTrue(listener.hasLogged(m -> m.source().path().contains(CommandWithLogger.class.getSimpleName())));