Add separate EventManager class

src/main/java/me/goudham/EventManager.java

@@ -0,0 +1,53 @@
+package me.goudham;
+
+import java.awt.image.BufferedImage;
+import java.util.ArrayList;
+import java.util.List;
+import me.goudham.event.ClipboardEvent;
+
+/**
+ * Stores all eventListeners and produces notifications that are to be consumed by users using {@link MyClipboard}
+ */
+class EventManager {
+    List<ClipboardEvent> eventListeners = new ArrayList<>();
+
+    /**
+     * Adds a {@link ClipboardEvent} to the {@code eventListeners}
+     *
+     * @param clipboardEvent The {@link ClipboardEvent} to be added
+     */
+    void subscribe(ClipboardEvent clipboardEvent) {
+        eventListeners.add(clipboardEvent);
+    }
+
+    /**
+     * Removes a {@link ClipboardEvent} from the {@code eventListeners}
+     *
+     * @param clipboardEvent The {@link ClipboardEvent} to be removed
+     */
+    void unsubscribe(ClipboardEvent clipboardEvent) {
+        eventListeners.remove(clipboardEvent);
+    }
+
+    /**
+     * Produces {@link String} change notifications to all consumers listening
+     *
+     * @param stringContent {@link String} to be consumed
+     */
+    void notifyStringEvent(String stringContent) {
+        for (ClipboardEvent clipboardEvent : eventListeners) {
+            clipboardEvent.onCopyString(stringContent);
+        }
+    }
+
+    /**
+     * Produces {@link BufferedImage} change notifications to all consumers listening
+     *
+     * @param imageContent {@link BufferedImage} to be consumed
+     */
+    void notifyImageEvent(BufferedImage imageContent) {
+        for (ClipboardEvent clipboardEvent : eventListeners) {
+            clipboardEvent.onCopyImage(imageContent);
+        }
+    }
+}