#113 Event Driven Architecture

Adds various changes including :
- Fixes to Javadoc
- Test refactoring and improvements
- Refactored EventDispatcher to be immutable
- Removed DynamicRouter interface since it not needed
- Renamed Channel to a more appropriate name - Handler

event-driven-architecture/src/test/java/com/iluwatar/eda/event/UserCreatedEventTest.java

@@ -0,0 +1,24 @@
+package com.iluwatar.eda.event;
+
+import com.iluwatar.eda.model.User;
+
+import org.junit.Test;
+
+import static org.junit.Assert.assertEquals;
+
+/**
+ * {@link UserCreatedEventTest} tests and verifies {@link Event} behaviour.
+ */
+public class UserCreatedEventTest {
+
+  /**
+   * This unit test should correctly return the {@link Event} class type when calling the
+   * {@link Event#getType() getType} method.
+   */
+  @Test
+  public void testGetEventType() {
+    User user = new User("iluwatar");
+    UserCreatedEvent userCreatedEvent = new UserCreatedEvent(user);
+    assertEquals(UserCreatedEvent.class, userCreatedEvent.getType());
+  }
+}

event-driven-architecture/src/test/java/com/iluwatar/eda/framework/EventDispatcherTest.java

@@ -0,0 +1,50 @@
+package com.iluwatar.eda.framework;
+
+import com.iluwatar.eda.framework.EventDispatcher;
+import com.iluwatar.eda.event.UserCreatedEvent;
+import com.iluwatar.eda.event.UserUpdatedEvent;
+import com.iluwatar.eda.handler.UserCreatedEventHandler;
+import com.iluwatar.eda.handler.UserUpdatedEventHandler;
+import com.iluwatar.eda.model.User;
+
+import org.junit.Test;
+
+import static org.mockito.Mockito.spy;
+import static org.mockito.Mockito.verify;
+
+/**
+ * Event Dispatcher unit tests to assert and verify correct event dispatcher behaviour
+ */
+public class EventDispatcherTest {
+
+  /**
+   * This unit test should register events and event handlers correctly with the event dispatcher
+   * and events should be dispatched accordingly.
+   */
+  @Test
+  public void testEventDriverPattern() {
+
+    EventDispatcher dispatcher = spy(new EventDispatcher());
+    UserCreatedEventHandler userCreatedEventHandler = spy(new UserCreatedEventHandler());
+    UserUpdatedEventHandler userUpdatedEventHandler = spy(new UserUpdatedEventHandler());
+    dispatcher.registerChannel(UserCreatedEvent.class, userCreatedEventHandler);
+    dispatcher.registerChannel(UserUpdatedEvent.class, userUpdatedEventHandler);
+
+    User user = new User("iluwatar");
+
+    UserCreatedEvent userCreatedEvent = new UserCreatedEvent(user);
+    UserUpdatedEvent userUpdatedEvent = new UserUpdatedEvent(user);
+
+    //fire a userCreatedEvent and verify that userCreatedEventHandler has been invoked.
+    dispatcher.onEvent(userCreatedEvent);
+    verify(userCreatedEventHandler).onEvent(userCreatedEvent);
+    verify(dispatcher).onEvent(userCreatedEvent);
+
+    //fire a userCreatedEvent and verify that userUpdatedEventHandler has been invoked.
+    dispatcher.onEvent(userUpdatedEvent);
+    verify(userUpdatedEventHandler).onEvent(userUpdatedEvent);
+    verify(dispatcher).onEvent(userUpdatedEvent);
+  }
+
+
+}