refactor: extract Antimony keywords into AntimonyConstants interface

core/src/org/sbml/jsbml/util/AntimonyConstants.java

@@ -0,0 +1,27 @@
+package org.sbml.jsbml.util;
+
+/**
+ * Interface defining constant keywords and operators used in the Antimony scripting language.
+ * Implementing this interface allows direct inheritance of all constants.
+ *
+ * @author Deepak Yadav
+ */
+public interface AntimonyConstants {
+    public static final String MODEL = "model ";
+    public static final String END = "end\n";
+    public static final String COMPARTMENT = "compartment ";
+    public static final String SPECIES = "species ";
+    public static final String SUBSTANCE_ONLY = "substanceOnly species ";
+    public static final String IN = " in ";
+    public static final String IRREVERSIBLE = " => ";
+    public static final String REVERSIBLE = " -> ";
+    public static final String ASSIGNMENT = " := ";
+    public static final String RATE = "' = ";
+    public static final String ALGEBRAIC = "0 = ";
+    public static final String AT = "at ";
+    public static final String AFTER = " after ";
+    public static final String DELAY = ", delay = ";
+    public static final String PRIORITY = ", priority = ";
+    public static final String T0_FALSE = ", t0 = false";
+    public static final String PERSISTENT_FALSE = ", persistent = false";
+}

core/src/org/sbml/jsbml/util/AntimonySerializer.java

@@ -22,7 +22,7 @@
  * 
  * @author Deepak Yadav
  */
-public class AntimonySerializer {
+public class AntimonySerializer implements AntimonyConstants {
 
     /**
      * Generic router for UI plugins (e.g., Eclipse, IntelliJ, VSCode). 
@@ -62,7 +62,7 @@ public static String toAntimony(Model model) {
         StringBuilder ant = new StringBuilder();
 
         String modelName = model.isSetName() ? model.getName() : model.getId();
-        ant.append("model ").append(modelName).append("()\n\n");
+        ant.append(MODEL).append(modelName).append("()\n\n");
 
         ant.append("  // Compartments\n");
         for (Compartment c : model.getListOfCompartments()) {
@@ -94,7 +94,7 @@ public static String toAntimony(Model model) {
         }
         ant.append("\n");
 
-        ant.append("end\n");
+        ant.append(END);
 
         return ant.toString();
     }
@@ -105,7 +105,7 @@ public static String toAntimony(Model model) {
     public static String toAntimony(Compartment c) {
         if (c == null) return "";
         StringBuilder ant = new StringBuilder();
-        ant.append("compartment ").append(c.getId());
+        ant.append(COMPARTMENT).append(c.getId());
         if (c.isSetSize()) {
             ant.append(" = ").append(c.getSize());
         }
@@ -126,9 +126,9 @@ public static String toAntimony(Species s) {
 
         // 1. Handle Substance Units
         if (hOSU) {
-            ant.append("substanceOnly species ");
+            ant.append(SUBSTANCE_ONLY);
         } else {
-            ant.append("species ");
+            ant.append(SPECIES);
         }
 
         // 2. Handle Boundary Condition
@@ -140,7 +140,7 @@ public static String toAntimony(Species s) {
 
         // Compartment assignment
         if (s.isSetCompartment()) {
-            ant.append(" in ").append(s.getCompartment());
+            ant.append(IN).append(s.getCompartment());
         }
 
         // 3. Handle Initial Values based on Concentration vs Amount assumptions
@@ -194,9 +194,9 @@ public static String toAntimony(Reaction r) {
 
         // 3. Reversibility (Antimony uses -> for reversible, => for irreversible)
         if (r.isSetReversible() && !r.getReversible()) {
-            ant.append(" => ");
+            ant.append(IRREVERSIBLE);
         } else {
-            ant.append(" -> ");
+            ant.append(REVERSIBLE);
         }
 
         // 4. Products
@@ -236,11 +236,11 @@ public static String toAntimony(Rule r) {
         String math = ASTNode.formulaToString(r.getMath());
 
         if (r instanceof AssignmentRule) {
-            return ((AssignmentRule) r).getVariable() + " := " + math + ";";
+            return ((AssignmentRule) r).getVariable() + ASSIGNMENT + math + ";";
         } else if (r instanceof RateRule) {
-            return ((RateRule) r).getVariable() + "' = " + math + ";";
+            return ((RateRule) r).getVariable() + RATE + math + ";";
         } else if (r instanceof AlgebraicRule) {
-            return "0 = " + math + ";";
+            return ALGEBRAIC + math + ";";
         }
 
         return "// Unsupported Rule type.";
@@ -258,29 +258,29 @@ public static String toAntimony(Event e) {
             ant.append(e.getId()).append(": ");
         }
 
-        ant.append("at ");
+        ant.append(AT);
         boolean hasTrigger = e.isSetTrigger() && e.getTrigger().isSetMath();
         boolean hasDelay = e.isSetDelay() && e.getDelay().isSetMath();
 
         if (hasDelay && hasTrigger) {
             ant.append(ASTNode.formulaToString(e.getDelay().getMath()));
-            ant.append(" after ");
+            ant.append(AFTER);
             ant.append(ASTNode.formulaToString(e.getTrigger().getMath()));
         } else if (hasTrigger) {
             ant.append(ASTNode.formulaToString(e.getTrigger().getMath()));
         }
 
         // Advanced Event Options
         if (e.isSetPriority() && e.getPriority().isSetMath()) {
-            ant.append(", priority = ").append(ASTNode.formulaToString(e.getPriority().getMath()));
+            ant.append(PRIORITY).append(ASTNode.formulaToString(e.getPriority().getMath()));
         }
         if (e.isSetTrigger()) {
             org.sbml.jsbml.Trigger t = e.getTrigger();
             if (t.isSetInitialValue() && !t.getInitialValue()) {
-                ant.append(", t0 = false");
+                ant.append(T0_FALSE);
             }
             if (t.isSetPersistent() && !t.getPersistent()) {
-                ant.append(", persistent = false");
+                ant.append(PERSISTENT_FALSE);
             }
         }
         ant.append(": ");

core/test/org/sbml/jsbml/util/AntimonyConstantsTest.java

@@ -0,0 +1,33 @@
+package org.sbml.jsbml.util;
+
+import org.junit.Test;
+import static org.junit.Assert.assertEquals;
+
+/**
+ * Tests for the {@link AntimonyConstants} interface.
+ * Ensures that core Antimony keywords and operators remain safely unchanged 
+ * to prevent parser regressions.
+ *
+ * @author Deepak Yadav
+ */
+
+public class AntimonyConstantsTest {
+
+    @Test
+    public void testCoreConstants() {
+        // Verify that the core structural constants haven't been accidentally altered
+        assertEquals("model ", AntimonyConstants.MODEL);
+        assertEquals("end\n", AntimonyConstants.END);
+        assertEquals("species ", AntimonyConstants.SPECIES);
+        assertEquals("compartment ", AntimonyConstants.COMPARTMENT);
+    }
+
+    @Test
+    public void testOperatorConstants() {
+        // Verify reaction and assignment operators
+        assertEquals(" => ", AntimonyConstants.IRREVERSIBLE);
+        assertEquals(" -> ", AntimonyConstants.REVERSIBLE);
+        assertEquals(" := ", AntimonyConstants.ASSIGNMENT);
+        assertEquals("' = ", AntimonyConstants.RATE);
+    }
+}