Fix stream reference parsing with surrounding whitespace

Author: EvenSol

src/main/java/neqsim/process/processmodel/ProcessSystem.java

@@ -3999,16 +3999,17 @@ public StreamInterface resolveStreamReference(String ref) {
     if (ref == null || ref.trim().isEmpty()) {
       return null;
     }
+    String normalizedRef = ref.trim();
 
     String unitName;
     String port = "outlet";
 
-    if (ref.contains(".")) {
-      String[] parts = ref.split("\\.", 2);
-      unitName = parts[0];
-      port = parts[1].toLowerCase();
+    if (normalizedRef.contains(".")) {
+      String[] parts = normalizedRef.split("\\.", 2);
+      unitName = parts[0].trim();
+      port = parts[1].trim().toLowerCase();
     } else {
-      unitName = ref;
+      unitName = normalizedRef;
     }
 
     ProcessEquipmentInterface unit = getUnit(unitName);

src/test/java/neqsim/process/processmodel/JsonProcessBuilderTest.java

@@ -65,6 +65,28 @@ void testBuildWithSeparatorAndCompressor() {
     assertNotNull(process.getUnit("Comp"));
   }
 
+  @Test
+  void testBuildWithWhitespaceAroundStreamReference() {
+    SystemSrkEos fluid = new SystemSrkEos(298.15, 50.0);
+    fluid.addComponent("methane", 0.85);
+    fluid.addComponent("ethane", 0.10);
+    fluid.addComponent("propane", 0.05);
+    fluid.setMixingRule("classic");
+
+    Stream feed = new Stream("feed", fluid);
+    neqsim.process.equipment.separator.Separator separator =
+        new neqsim.process.equipment.separator.Separator("HP Sep", feed);
+    ProcessSystem process = new ProcessSystem();
+    process.add(feed);
+    process.add(separator);
+
+    assertNotNull(process.resolveStreamReference("  feed  "),
+        "resolveStreamReference should trim whitespace for plain stream names");
+    StreamInterface gasOutWithWhitespace = process.resolveStreamReference("  HP Sep. gasOut  ");
+    assertNotNull(gasOutWithWhitespace,
+        "resolveStreamReference should trim whitespace around unit and port tokens");
+  }
+
   @Test
   void testBuildWithMultipleFluids() {
     String json = "{" + "\"fluids\": {" + "  \"gas\": {" + "    \"model\": \"SRK\","