[core] Introduce ScheduledAction.Kind for blocking and non-blocking actions

smack-core/src/main/java/org/jivesoftware/smack/AbstractXMPPConnection.java

@@ -2163,7 +2163,7 @@ public abstract class AbstractXMPPConnection implements XMPPConnection {
     }
 
     protected static ScheduledAction schedule(Runnable runnable, long delay, TimeUnit unit) {
-        return SMACK_REACTOR.schedule(runnable, delay, unit);
+        return SMACK_REACTOR.schedule(runnable, delay, unit, ScheduledAction.Kind.NonBlocking);
     }
 
     protected void onStreamOpen(XmlPullParser parser) {

smack-core/src/main/java/org/jivesoftware/smack/Manager.java

@@ -54,6 +54,14 @@ public abstract class Manager {
     }
 
     protected static final ScheduledAction schedule(Runnable runnable, long delay, TimeUnit unit) {
-        return AbstractXMPPConnection.SMACK_REACTOR.schedule(runnable, delay, unit);
+        return schedule(runnable, delay, unit, ScheduledAction.Kind.NonBlocking);
+    }
+
+    protected static final ScheduledAction scheduleBlocking(Runnable runnable, long delay, TimeUnit unit) {
+        return schedule(runnable, delay, unit, ScheduledAction.Kind.Blocking);
+    }
+
+    protected static final ScheduledAction schedule(Runnable runnable, long delay, TimeUnit unit, ScheduledAction.Kind scheduledActionKind) {
+        return AbstractXMPPConnection.SMACK_REACTOR.schedule(runnable, delay, unit, scheduledActionKind);
     }
 }

smack-core/src/main/java/org/jivesoftware/smack/ScheduledAction.java

@@ -20,16 +20,25 @@ import java.util.Date;
 import java.util.concurrent.Delayed;
 import java.util.concurrent.TimeUnit;
 
+import org.jivesoftware.smack.util.Async;
+
 public class ScheduledAction implements Delayed {
 
-    final Runnable action;
+    enum Kind {
+        NonBlocking,
+        Blocking,
+    }
+
+    private final Runnable action;
     final Date releaseTime;
     final SmackReactor smackReactor;
+    final Kind kind;
 
-    ScheduledAction(Runnable action, Date releaseTime, SmackReactor smackReactor) {
+    ScheduledAction(Runnable action, Date releaseTime, SmackReactor smackReactor, Kind kind) {
         this.action = action;
         this.releaseTime = releaseTime;
         this.smackReactor = smackReactor;
+        this.kind = kind;
     }
 
     /**
@@ -68,4 +77,15 @@ public class ScheduledAction implements Delayed {
         long delayInMillis = getTimeToDueMillis();
         return unit.convert(delayInMillis, TimeUnit.MILLISECONDS);
     }
+
+    void run() {
+        switch (kind) {
+        case NonBlocking:
+            action.run();
+            break;
+        case Blocking:
+            Async.go(() -> action.run());
+            break;
+        }
+    }
 }

smack-core/src/main/java/org/jivesoftware/smack/SmackReactor.java

@@ -145,10 +145,10 @@ public class SmackReactor {
         }
     }
 
-    ScheduledAction schedule(Runnable runnable, long delay, TimeUnit unit) {
+    ScheduledAction schedule(Runnable runnable, long delay, TimeUnit unit, ScheduledAction.Kind scheduledActionKind) {
         long releaseTimeEpoch = System.currentTimeMillis() + unit.toMillis(delay);
         Date releaseTimeDate = new Date(releaseTimeEpoch);
-        ScheduledAction scheduledAction = new ScheduledAction(runnable, releaseTimeDate, this);
+        ScheduledAction scheduledAction = new ScheduledAction(runnable, releaseTimeDate, this, scheduledActionKind);
         scheduledActions.add(scheduledAction);
         selector.wakeup();
         return scheduledAction;
@@ -206,7 +206,7 @@ public class SmackReactor {
             }
 
             if (dueScheduledAction != null) {
-                dueScheduledAction.action.run();
+                dueScheduledAction.run();
                 return;
             }