modules/graphics/src/main/java/com/sun/javafx/tk/quantum/QuantumToolkit.java

rev 8895 : RT-39689: Better docs and error checking if Printing or Dialogs called from Animation

@@ -192,11 +192,11 @@
 
     private AtomicBoolean           toolkitRunning = new AtomicBoolean(false);
     private AtomicBoolean           animationRunning = new AtomicBoolean(false);
     private AtomicBoolean           nextPulseRequested = new AtomicBoolean(false);
     private AtomicBoolean           pulseRunning = new AtomicBoolean(false);
-    private boolean                 inPulse = false;
+    private int                     inPulse = 0;
     private CountDownLatch          launchLatch = new CountDownLatch(1);
 
     final int                       PULSE_INTERVAL = (int)(TimeUnit.SECONDS.toMillis(1L) / getRefreshRate());
     final int                       FULLSPEED_INTERVAL = 1;     // ms
     boolean                         nativeSystemVsync = false;

@@ -498,21 +498,21 @@
 
             if (!toolkitRunning.get()) {
                 return;
             }
             nextPulseRequested.set(false);
-            inPulse = true;
+            inPulse++;
             if (animationRunnable != null) {
                 animationRunning.set(true);
                 animationRunnable.run();
             } else {
                 animationRunning.set(false);
             }
             firePulse();
             if (collect) collector.renderAll();
         } finally {
-            inPulse = false;
+            inPulse--;
             endPulseRunning();
             if (PULSE_LOGGING_ENABLED) {
                 PulseLogger.pulseEnd();
             }
         }

@@ -553,17 +553,22 @@
         stage.setRTL(rtl);
         stage.init(systemMenu);
         return stage;
     }
 
+    @Override public boolean canStartNestedEventLoop() {
+        return inPulse == 0;
+    }
+
     @Override public Object enterNestedEventLoop(Object key) {
         checkFxUserThread();
 
         if (key == null) {
             throw new NullPointerException();
         }
-        if (inPulse) {
+
+        if (!canStartNestedEventLoop()) {
             throw new IllegalStateException("Nested event loops are allowed only while handling system events");
         }
 
         if (eventLoopMap == null) {
             eventLoopMap = new HashMap<>();