Convert "wait for save" dialog to JavaFX

src/main/java/org/jabref/gui/JabRefFrame.java

@@ -502,17 +502,8 @@ public boolean quit() {
             context.getDatabaseFile().map(File::getAbsolutePath).ifPresent(filenames::add);
         }
 
-        // Wait for save operations to finish
-        for (int i = 0; i < tabbedPane.getTabs().size(); i++) {
-            if (getBasePanelAt(i).isSaving()) {
-                // There is a database still being saved, so we need to wait.
-                WaitForSaveOperation w = new WaitForSaveOperation(this);
-                w.show(); // This method won't return until canceled or the save operation is done.
-                if (w.canceled()) {
-                    return false; // The user clicked cancel.
-                }
-            }
-        }
+        WaitForSaveFinishedDialog waitForSaveFinishedDialog = new WaitForSaveFinishedDialog(dialogService);
+        waitForSaveFinishedDialog.showAndWait(getBasePanelList());
 
         // Good bye!
         tearDownJabRef(filenames);

src/main/java/org/jabref/gui/WaitForSaveFinishedDialog.java

@@ -0,0 +1,43 @@
+package org.jabref.gui;
+
+import java.util.List;
+
+import javafx.concurrent.Task;
+
+import org.jabref.logic.l10n.Localization;
+
+/**
+ * Dialog shown when closing of application needs to wait for a save operation to finish.
+ */
+public class WaitForSaveFinishedDialog {
+
+    private final DialogService dialogService;
+
+    public WaitForSaveFinishedDialog(DialogService dialogService) {
+        this.dialogService = dialogService;
+    }
+
+    public void showAndWait(List<BasePanel> basePanels) {
+        if (basePanels.stream().anyMatch(BasePanel::isSaving)) {
+            Task<Void> waitForSaveFinished = new Task<Void>() {
+                @Override
+                protected Void call() throws Exception {
+                    while (basePanels.stream().anyMatch(BasePanel::isSaving)) {
+                        if (isCancelled()) {
+                            return null;
+                        } else {
+                            Thread.sleep(100);
+                        }
+                    }
+                    return null;
+                }
+            };
+
+            dialogService.showProgressDialogAndWait(
+                    Localization.lang("Please wait..."),
+                    Localization.lang("Waiting for save operation to finish") + "...",
+                    waitForSaveFinished
+            );
+        }
+    }
+}