Add event listeners to notify classes of clipboard events

src/main/java/me/goudham/listener/ClipboardListener.java

@@ -1,5 +1,20 @@
 package me.goudham.listener;
 
-public interface ClipboardListener {
-    void execute();
+import java.util.ArrayList;
+import java.util.List;
+
+public abstract class ClipboardListener {
+    List<ClipboardEvent> eventsListener = new ArrayList<>();
+
+    public abstract void execute();
+
+    public void addEventListener(ClipboardEvent clipboardEvent) {
+        if (!eventsListener.contains(clipboardEvent)) {
+            eventsListener.add(clipboardEvent);
+        }
+    }
+
+    public void removeEventListener(ClipboardEvent clipboardEvent) {
+        eventsListener.remove(clipboardEvent);
+    }
 }

src/main/java/me/goudham/listener/MacClipboardListener.java

@@ -13,42 +13,41 @@ import java.util.concurrent.ScheduledExecutorService;
 import java.util.concurrent.TimeUnit;
 import me.goudham.model.MyClipboardContent;
 import me.goudham.util.ClipboardUtils;
-import org.jetbrains.annotations.NotNull;
 
 import static me.goudham.model.Contents.IMAGE;
 import static me.goudham.model.Contents.STRING;
 
-public class MacClipboardListener implements ClipboardListener {
+public class MacClipboardListener extends ClipboardListener {
     private final Clipboard clipboard = Toolkit.getDefaultToolkit().getSystemClipboard();
-    private final @NotNull ClipboardEvent clipboardEvent;
 
-    public MacClipboardListener(@NotNull ClipboardEvent clipboardEvent) {
-        this.clipboardEvent = clipboardEvent;
-    }
+    public MacClipboardListener() { }
 
     @Override
     public void execute() {
         Transferable oldClipboardContents = clipboard.getContents(null);
-        final MyClipboardContent<?>[] myOldClipboardContentsArray = new MyClipboardContent[]{ ClipboardUtils.getClipboardContents(oldClipboardContents, clipboard) };
+        final MyClipboardContent<?, ?>[] myClipboardContents = new MyClipboardContent[]{ ClipboardUtils.getClipboardContents(oldClipboardContents, clipboard) };
 
         ScheduledExecutorService executor = Executors.newSingleThreadScheduledExecutor();
         executor.scheduleAtFixedRate(() -> {
             Transferable newClipboardContents = clipboard.getContents(null);
-            MyClipboardContent<?> myNewClipboardContents = new MyClipboardContent<>("");
 
             try {
                 if (STRING.isAvailable(clipboard)) {
-                    myNewClipboardContents.setContent(newClipboardContents.getTransferData(STRING.getDataFlavor()));
-                    if (!myNewClipboardContents.getContent().equals(myOldClipboardContentsArray[0].getContent())) {
-                        clipboardEvent.onCopyString((String) myNewClipboardContents.getContent());
-                        myOldClipboardContentsArray[0].setContent(myNewClipboardContents.getContent());
+                    myClipboardContents[0].setNewContent(newClipboardContents.getTransferData(STRING.getDataFlavor()));
+                    if (!myClipboardContents[0].getNewContent().equals(myClipboardContents[0].getOldContent())) {
+                        for (ClipboardEvent clipboardEvent : eventsListener) {
+                            clipboardEvent.onCopyString((String) myClipboardContents[0].getNewContent());
+                        }
+                        myClipboardContents[0].setOldContent(myClipboardContents[0].getNewContent());
                     }
                 } else if (IMAGE.isAvailable(clipboard)) {
                     BufferedImage bufferedImage = ClipboardUtils.convertToBufferedImage((Image) newClipboardContents.getTransferData(IMAGE.getDataFlavor()));
-                    myNewClipboardContents.setContent(new Dimension(bufferedImage.getWidth(), bufferedImage.getHeight()));
-                    if (!myNewClipboardContents.getContent().equals(myOldClipboardContentsArray[0].getContent())) {
+                    myClipboardContents[0].setNewContent(new Dimension(bufferedImage.getWidth(), bufferedImage.getHeight()));
+                    if (!myClipboardContents[0].getNewContent().equals(myClipboardContents[0].getOldContent())) {
+                        for (ClipboardEvent clipboardEvent : eventsListener) {
                             clipboardEvent.onCopyImage(bufferedImage);
-                        myOldClipboardContentsArray[0].setContent(myNewClipboardContents.getContent());
+                        }
+                        myClipboardContents[0].setOldContent(myClipboardContents[0].getNewContent());
                     }
                 }
             } catch (UnsupportedFlavorException | IOException exp) {

src/main/java/me/goudham/listener/WindowsOrUnixClipboardListener.java

@@ -10,15 +10,14 @@ import java.awt.datatransfer.UnsupportedFlavorException;
 import java.awt.image.BufferedImage;
 import java.io.IOException;
 import me.goudham.util.ClipboardUtils;
-import org.jetbrains.annotations.NotNull;
 
-public class WindowsOrUnixClipboardListener extends Thread implements ClipboardListener, ClipboardOwner {
+import static java.lang.Thread.currentThread;
+import static java.lang.Thread.sleep;
+
+public class WindowsOrUnixClipboardListener extends ClipboardListener implements Runnable, ClipboardOwner {
     private final Clipboard clipboard = Toolkit.getDefaultToolkit().getSystemClipboard();
-    private final @NotNull ClipboardEvent clipboardEvent;
 
-    public WindowsOrUnixClipboardListener(@NotNull ClipboardEvent clipboardEvent) {
-        this.clipboardEvent = clipboardEvent;
-    }
+    public WindowsOrUnixClipboardListener() { }
 
     @Override
     public void lostOwnership(Clipboard oldClipboard, Transferable oldClipboardContents) {
@@ -36,11 +35,15 @@ public class WindowsOrUnixClipboardListener extends Thread implements ClipboardL
         try {
             if (oldClipboard.isDataFlavorAvailable(DataFlavor.stringFlavor)) {
                 String stringContent = (String) newClipboardContents.getTransferData(DataFlavor.stringFlavor);
+                for (ClipboardEvent clipboardEvent : eventsListener) {
                     clipboardEvent.onCopyString(stringContent);
+                }
             } else if (oldClipboard.isDataFlavorAvailable(DataFlavor.imageFlavor)) {
                 BufferedImage imageContent = ClipboardUtils.convertToBufferedImage((Image) newClipboardContents.getTransferData(DataFlavor.imageFlavor));
+                for (ClipboardEvent clipboardEvent : eventsListener) {
                     clipboardEvent.onCopyImage(imageContent);
                 }
+            }
         } catch (UnsupportedFlavorException | IOException ignored) {
         }
     }
@@ -59,9 +62,14 @@ public class WindowsOrUnixClipboardListener extends Thread implements ClipboardL
     }
 
     @Override
-    public void execute() {
+    public void run() {
         Transferable currentClipboardContents = clipboard.getContents(null);
         processContents(clipboard, currentClipboardContents);
         regainOwnership(clipboard, currentClipboardContents);
     }
+
+    @Override
+    public void execute() {
+        run();
+    }
 }