# HG changeset patch
# User mbalao
# Date 1539350455 -7200
#      Fri Oct 12 15:20:55 2018 +0200
# Node ID e6e3bdf4f789b2e287c35fe1ca50473ead713fc6
# Parent  354fb27fd38ac0bcab1363ae5316b533c07214c7
8204142: AWT hang occurs when sequenced events arrive out of sequence in multiple AppContexts
Summary: Synchronization of SequencedEvent events from different AppContexts fixed

diff --git a/src/java.desktop/share/classes/java/awt/SequencedEvent.java b/src/java.desktop/share/classes/java/awt/SequencedEvent.java
--- a/src/java.desktop/share/classes/java/awt/SequencedEvent.java
+++ b/src/java.desktop/share/classes/java/awt/SequencedEvent.java
@@ -27,6 +27,7 @@
 
 import java.security.AccessController;
 import java.security.PrivilegedAction;
+import java.util.Iterator;
 import java.util.LinkedList;
 import sun.awt.AWTAccessor;
 import sun.awt.AppContext;
@@ -56,6 +57,7 @@
     private final AWTEvent nested;
     private AppContext appContext;
     private boolean disposed;
+    private final LinkedList<AWTEvent> pendingEvents = new LinkedList<>();
 
     private static boolean fxAppThreadIsDispatchThread;
     private Thread fxCheckSequenceThread;
@@ -81,6 +83,34 @@
         });
     }
 
+    private static final class SequencedEventsFilter implements EventFilter {
+        private final SequencedEvent currentSequencedEvent;
+        private SequencedEventsFilter(SequencedEvent currentSequencedEvent) {
+            this.currentSequencedEvent = currentSequencedEvent;
+        }
+        @Override
+        public FilterAction acceptEvent(AWTEvent ev) {
+            if (ev.getID() == ID) {
+                // Move forward dispatching only if the event is previous
+                // in SequencedEvent.list. Otherwise, hold it for reposting later.
+                synchronized (SequencedEvent.class) {
+                    Iterator<SequencedEvent> it = list.iterator();
+                    while (it.hasNext()) {
+                        SequencedEvent iev = it.next();
+                        if (iev.equals(currentSequencedEvent)) {
+                            break;
+                        } else if (iev.equals(ev)) {
+                            return FilterAction.ACCEPT;
+                        }
+                    }
+                }
+                currentSequencedEvent.pendingEvents.add(ev);
+                return FilterAction.REJECT;
+            }
+            return FilterAction.ACCEPT;
+        }
+    }
+
     /**
      * Constructs a new SequencedEvent which will dispatch the specified
      * nested event.
@@ -135,7 +165,8 @@
                     if (Thread.currentThread() instanceof EventDispatchThread) {
                         EventDispatchThread edt = (EventDispatchThread)
                                 Thread.currentThread();
-                        edt.pumpEvents(ID, () -> !SequencedEvent.this.isFirstOrDisposed());
+                        edt.pumpEventsForFilter(() -> !SequencedEvent.this.isFirstOrDisposed(),
+                                new SequencedEventsFilter(this));
                     } else {
                         if (fxAppThreadIsDispatchThread) {
                             fxCheckSequenceThread.start();
@@ -239,10 +270,6 @@
             }
             disposed = true;
         }
-        // Wake myself up
-        if (appContext != null) {
-            SunToolkit.postEvent(appContext, new SentEvent());
-        }
 
         SequencedEvent next = null;
 
@@ -263,5 +290,9 @@
         if (next != null && next.appContext != null) {
             SunToolkit.postEvent(next.appContext, new SentEvent());
         }
+
+        for(AWTEvent e : pendingEvents) {
+            SunToolkit.postEvent(appContext, e);
+        }
     }
 }