Waiting for PTAG before executing startup reactions

Also, now `_react()` is called when `this._isDone` is false and LTC is not
sent if any of network input port is `unknown`.

Author: byeonggiljun

src/core/federation.ts

@@ -1431,6 +1431,11 @@ export class FederatedApp extends App {
         return false;
       }
     }
+    if (this.maxLevelAllowedToAdvance != Number.MAX_SAFE_INTEGER) {
+      // The reaction queue is empty but some network receivers are waiting for
+      // network inputs.
+      return false;
+    }
     Log.global.debug("Finished handling all events at current time.");
     return true;
   }
@@ -1875,6 +1880,23 @@ export class FederatedApp extends App {
     }
   }
 
+  /**
+   * Start executing reactions.
+   */
+  protected _startExecuting(): void {
+    Log.info(this, () => Log.hr);
+    Log.info(this, () => Log.hr);
+
+    Log.info(
+      this,
+      () => `>>> Start of execution: ${this.util.getCurrentTag()}`
+    );
+    Log.info(this, () => Log.hr);
+
+    // Send RTI a NET and wait for PTAG or TAG.
+    this.sendRTINextEventTag(this.util.getCurrentTag());
+  }
+
   /**
    * @override
    * Register this federated app with the RTI and request a start time.

src/core/reactor.ts

@@ -1835,7 +1835,9 @@ export class App extends Reactor {
 
   /**
    * Stores whether the current tag's reactions queue is empty.
-   * This will be false when a federate waits some network inputs.
+   * This will be false when a federate waits for network inputs.
+   * Note that this should be initialized with false to handle startup
+   * reactions of each federate.
    */
   private _isDone = false;
 
@@ -2388,8 +2390,10 @@ export class App extends Reactor {
    */
   private _next(): void {
     let nextEvent = this._eventQ.peek();
-    if (nextEvent != null) {
-      if (this._isDone) {
+    if (nextEvent != null || !this._isDone) {
+      if (nextEvent != null && this._isDone) {
+        // We're trying to advance a tag to the next event.
+
         // Check whether the next event can be handled, or not quite yet.
         // A holdup can occur in a federated execution.
         if (!this._canProceed(nextEvent)) {