Add event bus POC

plugin/src/software/aws/toolkits/eclipse/amazonq/broker/EventBroker.java

@@ -0,0 +1,39 @@
+// Copyright 2024 Amazon.com, Inc. or its affiliates. All Rights Reserved.
+// SPDX-License-Identifier: Apache-2.0
+
+package software.aws.toolkits.eclipse.amazonq.broker;
+
+import java.lang.reflect.ParameterizedType;
+
+import rx.Observable;
+import rx.Observer;
+import rx.subjects.PublishSubject;
+
+public final class EventBroker {
+
+    private static final EventBroker INSTANCE;
+    private final PublishSubject<Object> eventBus = PublishSubject.create();
+
+    static {
+        INSTANCE = new EventBroker();
+    }
+
+    public static EventBroker getInstance() {
+        return INSTANCE;
+    }
+
+    public void postEvent(final Object event) {
+        eventBus.onNext(event);
+    }
+
+    @SuppressWarnings("unchecked")
+    public <T> void subscribe(final Observer<T> observer) {
+        eventBus.ofType((Class<T>) ((ParameterizedType) observer.getClass()
+                .getGenericInterfaces()[0]).getActualTypeArguments()[0]).subscribe(observer);
+    }
+
+    public <T> Observable<T> ofObservable(final Class<T> eventType) {
+        return eventBus.ofType(eventType);
+    }
+
+}

plugin/src/software/aws/toolkits/eclipse/amazonq/events/TestEvent.java

@@ -0,0 +1,18 @@
+// Copyright 2024 Amazon.com, Inc. or its affiliates. All Rights Reserved.
+// SPDX-License-Identifier: Apache-2.0
+
+package software.aws.toolkits.eclipse.amazonq.events;
+
+public final class TestEvent {
+
+    private final String message;
+
+    public TestEvent(final String message) {
+        this.message = message;
+    }
+
+    public String getMessage() {
+        return message;
+    }
+
+}

plugin/src/software/aws/toolkits/eclipse/amazonq/publishers/TestPublisher.java

@@ -0,0 +1,22 @@
+// Copyright 2024 Amazon.com, Inc. or its affiliates. All Rights Reserved.
+// SPDX-License-Identifier: Apache-2.0
+
+package software.aws.toolkits.eclipse.amazonq.publishers;
+
+import software.aws.toolkits.eclipse.amazonq.broker.EventBroker;
+import software.aws.toolkits.eclipse.amazonq.events.TestEvent;
+
+public final class TestPublisher {
+
+    private final EventBroker eventBroker;
+
+    public TestPublisher() {
+        eventBroker = EventBroker.getInstance();
+
+        for (int i = 0; i < 10; i++) {
+            String message = "Test message " + i;
+            eventBroker.postEvent(new TestEvent(message));
+        }
+    }
+
+}

plugin/src/software/aws/toolkits/eclipse/amazonq/subscribers/TestSubscribers.java

@@ -0,0 +1,48 @@
+// Copyright 2024 Amazon.com, Inc. or its affiliates. All Rights Reserved.
+// SPDX-License-Identifier: Apache-2.0
+
+package software.aws.toolkits.eclipse.amazonq.subscribers;
+
+import rx.Observer;
+import software.aws.toolkits.eclipse.amazonq.broker.EventBroker;
+import software.aws.toolkits.eclipse.amazonq.events.TestEvent;
+
+public final class TestSubscribers {
+
+    public TestSubscribers() {
+        fromObserver();
+        fromObservable();
+    }
+
+    public void fromObserver() {
+        Observer<TestEvent> observer = new Observer<>() {
+            @Override
+            public void onNext(final TestEvent event) {
+                System.out.println(event.getMessage());
+            }
+
+            @Override
+            public void onError(final Throwable error) {
+                System.out.println(error.getMessage());
+            }
+
+            @Override
+            public void onCompleted() {
+                System.out.println("Completed");
+            }
+        };
+
+        // Direct subscription
+        EventBroker.getInstance().subscribe(observer);
+
+        // Subscribe using observable
+        EventBroker.getInstance().ofObservable(TestEvent.class).subscribe(observer);
+    }
+
+    public void fromObservable() {
+        EventBroker.getInstance().ofObservable(TestEvent.class).subscribe(
+                event -> System.out.println(event.getMessage()),
+                throwable -> System.out.println(throwable.getMessage()), () -> System.out.println("Complete"));
+    }
+
+}

plugin/src/software/aws/toolkits/eclipse/amazonq/views/AmazonQView.java

@@ -9,22 +9,27 @@
 import org.eclipse.swt.widgets.Display;
 import org.eclipse.ui.part.ViewPart;
 
+import rx.Observer;
+import software.aws.toolkits.eclipse.amazonq.broker.EventBroker;
 import software.aws.toolkits.eclipse.amazonq.controllers.AmazonQViewController;
+import software.aws.toolkits.eclipse.amazonq.events.TestEvent;
 import software.aws.toolkits.eclipse.amazonq.lsp.auth.AuthStatusChangedListener;
 import software.aws.toolkits.eclipse.amazonq.lsp.auth.AuthStatusProvider;
 import software.aws.toolkits.eclipse.amazonq.lsp.auth.model.AuthState;
 import software.aws.toolkits.eclipse.amazonq.plugin.Activator;
 import software.aws.toolkits.eclipse.amazonq.util.ThemeDetector;
 import software.aws.toolkits.eclipse.amazonq.views.actions.AmazonQCommonActions;
 
-public abstract class AmazonQView extends ViewPart implements AuthStatusChangedListener {
+public abstract class AmazonQView extends ViewPart implements AuthStatusChangedListener,
+        Observer<TestEvent> {
 
     private AmazonQViewController viewController;
     private AmazonQCommonActions amazonQCommonActions;
     private static final ThemeDetector THEME_DETECTOR = new ThemeDetector();
 
     protected AmazonQView() {
         this.viewController = new AmazonQViewController();
+        EventBroker.getInstance().subscribe(this);
     }
 
     public final Browser getBrowser() {
@@ -127,4 +132,19 @@ public void dispose() {
         super.dispose();
     }
 
+    @Override
+    public final void onNext(final TestEvent event) {
+        System.out.println(event.getMessage());
+    }
+
+    @Override
+    public final void onError(final Throwable throwable) {
+        System.out.println(throwable.getMessage());
+    }
+
+    @Override
+    public final void onCompleted() {
+        System.out.println("Completed");
+    }
+
 }