Fixed issue 2.6.89 by calling JOptionPane in a Swing event thread (#9091

)

* Modified EventThreadJOptionPane.showConfirmDialog to call JOptionPane and JDialog constructor in a Swing event thread if not in one presently. This fixes issue 2.6.89.

* Fixed CheckStyle issues with modified code.

Co-authored-by: Brian Kelly <bkelly1@mymail.mines.edu>

lib/swing-lib/src/main/java/org/triplea/swing/EventThreadJOptionPane.java

@@ -211,42 +211,66 @@ public enum ConfirmDialogType {
    * @return True if user confirms, false if user closes the confirmation dialog or selects no.
    */
   public static boolean showConfirmDialog(
-      final @Nullable Component parentComponent,
-      final @Nullable Object message,
-      final @Nullable String title,
-      final ConfirmDialogType confirmDialogType) {
-
-    // Construct a 'JDialog' the "hard" way through a JOptionPane so that we can
-    // set modal to be false.
-    final JOptionPane optionPane =
-        new JOptionPane(
-            message, JOptionPane.QUESTION_MESSAGE, confirmDialogType.optionTypeMagicNumber);
-    final JDialog dialog = optionPane.createDialog(parentComponent, title);
-    dialog.setAlwaysOnTop(true);
-    if (!SwingUtilities.isEventDispatchThread()) {
-      dialog.setModal(false);
-    }
+          final @Nullable Component parentComponent,
+          final @Nullable Object message,
+          final @Nullable String title,
+          final ConfirmDialogType confirmDialogType) {
 
+    // We want to construct a 'JDialog' the "hard" way through a JOptionPane so
+    // that we can set modal to be false.
     // Only modal dialogs are blocking. To mimic this, we use a latch to block once
     // the dialog is set to visible. We use a property listener to capture the users
     // confirmation choice and to unblock.
     final CountDownLatch latch = new CountDownLatch(1);
     final AtomicReference<Boolean> confirmation = new AtomicReference<>();
-    optionPane.addPropertyChangeListener(
-        JOptionPane.VALUE_PROPERTY,
-        ignored -> {
-          final Object selectedValue = optionPane.getValue();
-          confirmation.set(selectedValue != null && JOptionPane.OK_OPTION == (int) selectedValue);
-          latch.countDown();
-          dialog.dispose();
-        });
 
+    // Swing components must be created in Swing event threads. If we are already
+    // in one, dialog creation is fairly easy.
     if (SwingUtilities.isEventDispatchThread()) {
+      final JOptionPane optionPane =
+              new JOptionPane(
+                      message, JOptionPane.QUESTION_MESSAGE,
+                      confirmDialogType.optionTypeMagicNumber);
+      final JDialog dialog = optionPane.createDialog(parentComponent, title);
+      dialog.setAlwaysOnTop(true);
+
+      optionPane.addPropertyChangeListener(
+              JOptionPane.VALUE_PROPERTY,
+              ignored -> {
+                final Object selectedValue = optionPane.getValue();
+                confirmation.set(selectedValue != null
+                        && JOptionPane.OK_OPTION == (int) selectedValue);
+                latch.countDown();
+                dialog.dispose();
+              });
+
       // modal dialog being set to visible is blocking
       dialog.setVisible(true);
+
+    // For non-Swing event threads, we must request our code be invoked and block manually
     } else {
-      // non modal dialog set to visible is not blocking and must be done on EDT
-      SwingUtilities.invokeLater(() -> dialog.setVisible(true));
+      SwingUtilities.invokeLater(() -> {
+        final JOptionPane optionPane =
+                new JOptionPane(message, JOptionPane.QUESTION_MESSAGE,
+                        confirmDialogType.optionTypeMagicNumber);
+        final JDialog dialog = optionPane.createDialog(parentComponent, title);
+        dialog.setAlwaysOnTop(true);
+        dialog.setModal(false);
+
+        optionPane.addPropertyChangeListener(
+                JOptionPane.VALUE_PROPERTY,
+                ignored -> {
+                  final Object selectedValue = optionPane.getValue();
+                  confirmation.set(selectedValue != null
+                          && JOptionPane.OK_OPTION == (int) selectedValue);
+                  latch.countDown();
+                  dialog.dispose();
+                });
+
+        // non modal dialog set to visible is not blocking and must be done on EDT
+        dialog.setVisible(true);
+      });
+
       try {
         // start blocking, wait for the dialog property event to fire to clear this latch
         latch.await();