Refactored GlobalEventBus

.idea/misc.xml

@@ -1,5 +1,10 @@
 <?xml version="1.0" encoding="UTF-8"?>
 <project version="4">
+  <component name="EntryPointsManager">
+    <list size="1">
+      <item index="0" class="java.lang.String" itemvalue="com.google.common.eventbus.Subscribe" />
+    </list>
+  </component>
   <component name="ExternalStorageConfigurationManager" enabled="true" />
   <component name="MavenProjectsManager">
     <option name="originalFiles">

src/main/java/org/toop/GlobalEventBus.java

@@ -1,13 +0,0 @@
-package org.toop;
-
-import com.google.common.eventbus.EventBus;
-
-public enum GlobalEventBus {
-    INSTANCE;
-
-    private final EventBus eventBus = new EventBus("global-bus");
-
-    public EventBus get() {
-        return eventBus;
-    }
-}

src/main/java/org/toop/LoggerListener.java

@@ -1,14 +0,0 @@
-package org.toop;
-
-import com.google.common.eventbus.Subscribe;
-import org.toop.server.*;
-
-public class LoggerListener {
-    @Subscribe
-    public void onCommand(CommandEvent event) {
-        System.out.printf("LOG: %s args=%s -> %s%n",
-                event.command(),
-                String.join(",", event.args()),
-                event.result());
-    }
-}

src/main/java/org/toop/Main.java

@@ -1,5 +1,7 @@
 package org.toop;
 
+import org.toop.eventbus.Events;
+import org.toop.eventbus.GlobalEventBus;
 import org.toop.server.Server;
 
 public class Main {
@@ -8,10 +10,23 @@ public class Main {
         Server server = new Server(Server.ServerBackend.LOCAL, "127.0.0.1", "5000");
         server.setBackend(Server.ServerBackend.REMOTE);
 
-        GlobalEventBus.INSTANCE.get().register(new LoggerListener());
+        GlobalEventBus.subscribeAndRegister(Events.ServerEvents.OnCommand.class, e -> {
+            if (e.command() == Server.Command.LOGIN) {
+                System.out.println("LOGIN command -> " + String.join(" ", e.args()));
+            }
+            else if (e.command() == Server.Command.HELP) {
+                System.out.println("HELP command -> " + String.join(" ", e.args()));
+            }
+        });
+
+        GlobalEventBus.subscribeAndRegister(Events.ServerEvents.OnChangingServerBackend.class, e -> {
+            System.out.println("Server backend has changed to -> " + e.backend());
+        });
 
         Server.Message msg = server.sendCommand(Server.Command.LOGIN, "move");
-        server.sendCommand(Server.Command.LOGIN, "test");
+        server.sendCommand(Server.Command.HELP, "test", "test2");
+
+        server.setBackend(Server.ServerBackend.REMOTE);
 
         System.out.println(msg);
         System.out.println(server);

src/main/java/org/toop/eventbus/Events.java

@@ -0,0 +1,23 @@
+package org.toop.eventbus;
+
+import org.toop.server.Server;
+
+/**
+ * Events that are used in the GlobalEventBus class.
+ */
+public class Events {
+
+    public static class ServerEvents {
+        /**
+         * Triggers when a command is sent to a server.
+         */
+        public record OnCommand(Server.Command command, String[] args, Server.Message result) {}
+
+        /**
+         * Triggers on changing the server backend.
+         */
+        public record OnChangingServerBackend(Server.ServerBackend backend) {}
+
+    }
+
+}

src/main/java/org/toop/eventbus/GlobalEventBus.java

@@ -0,0 +1,90 @@
+package org.toop.eventbus;
+
+import com.google.common.eventbus.EventBus;
+import com.google.common.eventbus.Subscribe;
+
+import java.util.function.Consumer;
+
+/**
+ * A singleton Event Bus to be used for creating, triggering and activating events.
+ */
+public enum GlobalEventBus {
+    /**
+     * The instance of the Event Bus.
+     */
+    INSTANCE;
+
+    /**
+     * Singleton event bus.
+     */
+    private final EventBus eventBus = new EventBus("global-bus");
+
+    /**
+     * Wraps a Consumer into a Guava @Subscribe-compatible listener.
+     *
+     * @return Singleton Event Bus
+     */
+    public EventBus get() {
+        return eventBus;
+    }
+
+    /**
+     * Wraps a Consumer into a Guava @Subscribe-compatible listener.
+     *
+     * @param type The event to be used. (e.g. Events.ServerCommand.class)
+     * @param action The function, or lambda to run when fired.
+     * @return Object to be used for registering an event.
+     */
+    public static <T> Object subscribe(Class<T> type, Consumer<T> action) {
+        return new Object() {
+            @Subscribe
+            public void handle(T event) {
+                action.accept(event);
+            }
+        };
+    }
+
+    /**
+     * Wraps a Consumer into a Guava @Subscribe-compatible listener and registers it.
+     *
+     * @param type The event to be used. (e.g. Events.ServerCommand.class)
+     * @param action The function, or lambda to run when fired.
+     * @return Object to be used for registering an event.
+     */
+    public static <T> Object subscribeAndRegister(Class<T> type, Consumer<T> action) {
+        Object listener = new Object() {
+            @Subscribe
+            public void handle(Object event) {
+                if (type.isInstance(event)) {
+                    action.accept(type.cast(event));
+                }
+            }
+        };
+        register(listener);
+        return listener;
+    }
+
+
+    /**
+     * Wrapper for registering a listener.
+     *
+     * @param listener The event listener to register.
+     */
+    public static void register(Object listener) {
+        GlobalEventBus.INSTANCE.get().register(listener);
+    }
+
+    /**
+     * Wrapper for unregistering a listener.
+     *
+     * @param listener The event listener to unregister.
+     */
+    public static void unregister(Object listener) {
+        GlobalEventBus.INSTANCE.get().unregister(listener);
+    }
+
+    public static void post(Object event) {
+        GlobalEventBus.INSTANCE.get().post(event);
+    }
+
+}

src/main/java/org/toop/server/CommandEvent.java

@@ -1,3 +0,0 @@
-package org.toop.server;
-
-public record CommandEvent(Server.Command command, String[] args, Server.Message result) {}

src/main/java/org/toop/server/Server.java

@@ -1,6 +1,7 @@
 package org.toop.server;
 
-import org.toop.GlobalEventBus;
+import org.toop.eventbus.Events;
+import org.toop.eventbus.GlobalEventBus;
 import org.toop.server.backend.*;
 import java.util.EnumSet;
 
@@ -48,7 +49,7 @@ public class Server {
 
     String ip;
     String port;
-    Backend backend;
+    IBackend backend;
 
     public Server(ServerBackend set_backend, String set_ip, String set_port) {
         ip = set_ip;
@@ -57,13 +58,19 @@ public class Server {
 
     }
 
-    public Backend getBackend() {
+    public IBackend getBackend() {
         return backend;
     }
 
     public void setBackend(ServerBackend backend) {
-        if (backend == ServerBackend.LOCAL) { this.backend = new Local(); }
+        if (backend == ServerBackend.LOCAL) {
-        else { this.backend = new Remote(); }
+            this.backend = new Local();
+            GlobalEventBus.post(new Events.ServerEvents.OnChangingServerBackend(ServerBackend.LOCAL));
+        }
+        else {
+            this.backend = new Remote();
+            GlobalEventBus.post(new Events.ServerEvents.OnChangingServerBackend(ServerBackend.REMOTE));
+        }
     }
 
     public String getIp() {
@@ -102,7 +109,7 @@ public class Server {
         }
         Message result = sendCommandString(command.toString());
 
-        GlobalEventBus.INSTANCE.get().post(new CommandEvent(command, new String[0], result));
+        GlobalEventBus.post(new Events.ServerEvents.OnCommand(command, new String[0], result));
 
         return sendCommandString(command.toString());
     }
@@ -132,7 +139,7 @@ public class Server {
 
         Message result = sendCommandString(String.join(" ", fullCommand));
 
-        GlobalEventBus.INSTANCE.get().post(new CommandEvent(command, args, result));
+        GlobalEventBus.post(new Events.ServerEvents.OnCommand(command, args, result));
 
         return result;
     }

src/main/java/org/toop/server/backend/IBackend.java

@@ -2,7 +2,7 @@ package org.toop.server.backend;
 
 import org.toop.server.Server;
 
-public interface Backend {
+public interface IBackend {
     Server.Message login(String username);
 }
 

src/main/java/org/toop/server/backend/Local.java

@@ -2,7 +2,7 @@ package org.toop.server.backend;
 
 import org.toop.server.Server;
 
-public class Local implements Backend {
+public class Local implements IBackend {
     @Override
     public Server.Message login(String username) {
         return null;

src/main/java/org/toop/server/backend/Remote.java

@@ -2,7 +2,7 @@ package org.toop.server.backend;
 
 import org.toop.server.Server;
 
-public class Remote implements Backend {
+public class Remote implements IBackend {
     @Override
     public Server.Message login(String username) {
         return null;