Merge pull request #706 from csmith/master

Add an interface for the event bus.

api/src/main/java/com/dmdirc/interfaces/EventBus.java

@@ -0,0 +1,60 @@
+/*
+ * Copyright (c) 2006-2016 DMDirc Developers
+ *
+ * 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.
+ */
+
+package com.dmdirc.interfaces;
+
+import com.dmdirc.events.DMDircEvent;
+
+/**
+ * An event bus offers facilities for publishing events to decoupled handlers.
+ */
+public interface EventBus {
+
+    /**
+     * Subscribe all handlers of the given listener. Any listener is only subscribed once; subsequent subscriptions of
+     * an already subscribed listener will be silently ignored.
+     */
+    void subscribe(Object listener);
+
+    /**
+     * Immediately remove all registered handlers (if any) of the given listener. When this call returns all handlers
+     * have effectively been removed and will not receive any messages.
+     *
+     * <p>A call to this method passing any object that is not subscribed will not have any effect and is silently
+     * ignored.
+     */
+    void unsubscribe(Object listener);
+
+    /**
+     * Synchronously publish a message to all registered listeners. This includes listeners defined for super types of
+     * the given message type, provided they are not configured to reject valid subtype. The call returns when all
+     * matching handlers of all registered listeners have been notified (invoked) of the message.
+     */
+    void publish(DMDircEvent message);
+
+    /**
+     * Asynchronously publish a message to all registered listeners. This includes listeners defined for super types of
+     * the given message type, provided they are not configured to reject valid subtype. The call returns immediately.
+     */
+    void publishAsync(DMDircEvent message);
+
+}

src/main/java/com/dmdirc/DMDircMBassador.java

@@ -23,24 +23,27 @@
 package com.dmdirc;
 
 import com.dmdirc.events.DMDircEvent;
-
-import org.slf4j.Logger;
-import org.slf4j.LoggerFactory;
+import com.dmdirc.interfaces.EventBus;
 
 import net.engio.mbassy.bus.MBassador;
 import net.engio.mbassy.bus.config.BusConfiguration;
 import net.engio.mbassy.bus.config.Feature;
 import net.engio.mbassy.bus.config.IBusConfiguration;
 
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
 import static com.dmdirc.util.LogUtils.APP_ERROR;
 
 /**
  * Generified MBassador.
  */
-public class DMDircMBassador extends MBassador<DMDircEvent> {
+public class DMDircMBassador implements EventBus {
 
     private static final Logger LOG = LoggerFactory.getLogger(DMDircMBassador.class);
 
+    private final MBassador<DMDircEvent> bus;
+
     public DMDircMBassador() {
         this(new BusConfiguration()
                 .addFeature(Feature.SyncPubSub.Default())
@@ -52,8 +55,28 @@ public class DMDircMBassador extends MBassador<DMDircEvent> {
 
     @SuppressWarnings("TypeMayBeWeakened")
     public DMDircMBassador(final IBusConfiguration configuration) {
-        super(configuration.addPublicationErrorHandler(
+        bus = new MBassador<>(configuration.addPublicationErrorHandler(
                 e -> LOG.error(APP_ERROR, e.getMessage(), e.getCause())));
     }
 
+    @Override
+    public void subscribe(Object listener) {
+        bus.subscribe(listener);
+    }
+
+    @Override
+    public void unsubscribe(Object listener) {
+        bus.unsubscribe(listener);
+    }
+
+    @Override
+    public void publish(DMDircEvent message) {
+        bus.publish(message);
+    }
+
+    @Override
+    public void publishAsync(DMDircEvent message) {
+        bus.publishAsync(message);
+    }
+
 }