From a9d3c61911df12dfef480d07dc8f9227ffde0683 Mon Sep 17 00:00:00 2001
From: Xiqinger <163422483+Xiqinger@users.noreply.github.com>
Date: Tue, 26 Mar 2024 16:42:49 +0800
Subject: [PATCH] add null pointer check to avoid null pointer exception.

---
 src/main/java/org/lemsml/jlems/core/run/StateInstance.java | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/src/main/java/org/lemsml/jlems/core/run/StateInstance.java b/src/main/java/org/lemsml/jlems/core/run/StateInstance.java
index 7595e156..a87ef92e 100644
--- a/src/main/java/org/lemsml/jlems/core/run/StateInstance.java
+++ b/src/main/java/org/lemsml/jlems/core/run/StateInstance.java
@@ -300,6 +300,9 @@ public void advance(StateRunnable parent, double t, double dt) throws RuntimeErr
 	
 
 	public void transitionTo(String rnm) throws RuntimeError {
+		if (regimeHM == null) {
+			throw new IllegalStateException("No Regimes.");
+		}
 		activeRegime = regimeHM.get(rnm);
 		activeRegime.enter();
 	}
@@ -314,6 +317,9 @@ public void doneInit() {
 
 	public void initRegime() throws RuntimeError {
 		if (activeRegime == null) {
+			if (regimeHM == null || regimeHM.isEmpty()) {
+				throw new IllegalStateException("No Regimes.");
+			}
 			activeRegime = regimeHM.get(regimeHM.keySet().iterator().next());
 			// TODO just picks random regime
 		}