feat: introduce core TreeNodeVisitor pattern scaffolding (#262)

core/src/org/sbml/jsbml/ASTNode.java

@@ -5056,4 +5056,15 @@ public void canonicalize() {
 		}
 	}
 
+  /**
+   * Accepts a generic visitor to traverse this component.
+   *
+   * @param <T> the return type of the visitor
+   * @param visitor the visitor implementation
+   * @return the result of the visitor operation
+   */
+  public <T> T accept(TreeNodeVisitor<T> visitor) {
+    return visitor.visit(this);
+  }
+
 }

core/src/org/sbml/jsbml/AbstractSBase.java

@@ -3492,4 +3492,16 @@ public String toSBML() {
     }
   }
 
-}
+  /**
+   * Accepts a generic visitor to traverse this SBase component.
+   *
+   * @param <T> the return type of the visitor
+   * @param visitor the visitor implementation
+   * @return the result of the visitor operation
+   */
+  @Override
+  public <T> T accept(TreeNodeVisitor<T> visitor) {
+    return visitor.visit(this);
+  }
+
+}

core/src/org/sbml/jsbml/Annotation.java

@@ -940,4 +940,15 @@ public void unsetNonRDFannotation() {
     }
   }
 
-}
+  /**
+   * Accepts a generic visitor to traverse this component.
+   *
+   * @param <T> the return type of the visitor
+   * @param visitor the visitor implementation
+   * @return the result of the visitor operation
+   */
+  public <T> T accept(TreeNodeVisitor<T> visitor) {
+    return visitor.visit(this);
+  }
+
+}

core/src/org/sbml/jsbml/CVTerm.java

@@ -28,6 +28,7 @@
 import javax.swing.tree.TreeNode;
 import javax.xml.stream.XMLStreamException;
 
+import org.sbml.jsbml.CVTerm.Qualifier;
 import org.sbml.jsbml.util.StringTools;
 import org.sbml.jsbml.util.TreeNodeAdapter;
 import org.sbml.jsbml.util.TreeNodeChangeEvent;
@@ -1405,4 +1406,15 @@ public void setUnknownQualifierName(String unknownQualifierName) {
     this.unknownQualifierName = unknownQualifierName;
   }
 
-}
+  /**
+   * Accepts a generic visitor to traverse this component.
+   *
+   * @param <T> the return type of the visitor
+   * @param visitor the visitor implementation
+   * @return the result of the visitor operation
+   */
+  public <T> T accept(TreeNodeVisitor<T> visitor) {
+    return visitor.visit(this);
+  }
+
+}

core/src/org/sbml/jsbml/Creator.java

@@ -550,4 +550,15 @@ public void unsetOrganization() {
     firePropertyChange(TreeNodeChangeEvent.organization, oldValue, organisation);
   }
 
-}
+  /**
+   * Accepts a generic visitor to traverse this component.
+   *
+   * @param <T> the return type of the visitor
+   * @param visitor the visitor implementation
+   * @return the result of the visitor operation
+   */
+  public <T> T accept(TreeNodeVisitor<T> visitor) {
+    return visitor.visit(this);
+  }
+
+}

core/src/org/sbml/jsbml/History.java

@@ -506,4 +506,16 @@ public String toString() {
 	}
     return result.toString();
   }
-}
+
+  /**
+   * Accepts a generic visitor to traverse this component.
+   *
+   * @param <T> the return type of the visitor
+   * @param visitor the visitor implementation
+   * @return the result of the visitor operation
+   */
+  public <T> T accept(TreeNodeVisitor<T> visitor) {
+    return visitor.visit(this);
+  }
+
+}

core/src/org/sbml/jsbml/TreeNodeVisitor.java

@@ -0,0 +1,32 @@
+package org.sbml.jsbml;
+
+import org.sbml.jsbml.util.TreeNodeWithChangeSupport;
+
+/**
+ * A generic visitor interface for traversing the JSBML tree structure.
+ * This allows external classes to operate on SBML components without
+ * modifying the core classes.
+ *
+ * @param <T> The return type of the visitor operations. Note that this generic 
+ * type may also be {@link Void} if nothing is to be returned.
+ * @author Deepak Yadav
+ */
+public interface TreeNodeVisitor<T> {
+
+    /**
+     * Primary traversal method for core SBML components.
+     *
+     * @param sbase the core SBML element to visit
+     * @return a result of type T
+     */
+    T visit(SBase sbase);
+
+    /**
+     * Fallback traversal method for auxiliary nodes (e.g., annotations, notes)
+     * that do not inherit from SBase but do inherit from TreeNodeWithChangeSupport.
+     *
+     * @param node the tree node to visit
+     * @return a result of type T
+     */
+    T visit(TreeNodeWithChangeSupport node);
+}

core/src/org/sbml/jsbml/ext/AbstractASTNodePlugin.java

@@ -31,6 +31,7 @@
 import org.sbml.jsbml.AbstractTreeNode;
 import org.sbml.jsbml.SBMLDocument;
 import org.sbml.jsbml.SBase;
+import org.sbml.jsbml.TreeNodeVisitor;
 import org.sbml.jsbml.util.TreeNodeChangeEvent;
 
 /**
@@ -355,4 +356,16 @@ public Map<String, String> writeXMLAttributes() {
     return new TreeMap<String, String>();
   }
 
+  /**
+     * Accepts a generic visitor to traverse this component.
+     *
+     * @param <T> the return type of the visitor
+     * @param visitor the visitor implementation
+     * @return the result of the visitor operation
+     */
+    @Override
+    public <T> T accept(TreeNodeVisitor<T> visitor) {
+        return visitor.visit(this);
+    }
+
 }

core/src/org/sbml/jsbml/ext/AbstractSBasePlugin.java

@@ -30,6 +30,7 @@
 import org.sbml.jsbml.AbstractTreeNode;
 import org.sbml.jsbml.SBMLDocument;
 import org.sbml.jsbml.SBase;
+import org.sbml.jsbml.TreeNodeVisitor;
 import org.sbml.jsbml.util.TreeNodeChangeEvent;
 
 /**
@@ -327,4 +328,16 @@ public Map<String, String> writeXMLAttributes() {
     return new TreeMap<String, String>();
   }
 
+  /**
+     * Accepts a generic visitor to traverse this component.
+     *
+     * @param <T> the return type of the visitor
+     * @param visitor the visitor implementation
+     * @return the result of the visitor operation
+     */
+    @Override
+    public <T> T accept(TreeNodeVisitor<T> visitor) {
+        return visitor.visit(this);
+    }
+
 }

core/src/org/sbml/jsbml/math/ASTBoolean.java

@@ -24,6 +24,7 @@
 import org.sbml.jsbml.ASTNode.Type;
 import org.sbml.jsbml.PropertyUndefinedError;
 import org.sbml.jsbml.SBMLException;
+import org.sbml.jsbml.TreeNodeVisitor;
 import org.sbml.jsbml.math.compiler.ASTNode2Compiler;
 import org.sbml.jsbml.math.compiler.ASTNode2Value;
 import org.sbml.jsbml.math.compiler.FormulaCompiler;
@@ -197,4 +198,15 @@ public String toMathML() {
     }
   }
 
+  /**
+   * Accepts a generic visitor to traverse this component.
+   *
+   * @param <T> the return type of the visitor
+   * @param visitor the visitor implementation
+   * @return the result of the visitor operation
+   */
+  public <T> T accept(TreeNodeVisitor<T> visitor) {
+    return visitor.visit(this);
+  }
+
 }

core/src/org/sbml/jsbml/math/ASTCSymbolAvogadroNode.java

@@ -24,6 +24,7 @@
 import org.sbml.jsbml.ASTNode;
 import org.sbml.jsbml.ASTNode.Type;
 import org.sbml.jsbml.PropertyUndefinedError;
+import org.sbml.jsbml.TreeNodeVisitor;
 import org.sbml.jsbml.math.compiler.ASTNode2Compiler;
 import org.sbml.jsbml.math.compiler.ASTNode2Value;
 import org.sbml.jsbml.util.Maths;
@@ -316,4 +317,15 @@ public void setName(String name) {
     firePropertyChange(TreeNodeChangeEvent.name, old, this.name);
   }
 
+  /**
+   * Accepts a generic visitor to traverse this component.
+   *
+   * @param <T> the return type of the visitor
+   * @param visitor the visitor implementation
+   * @return the result of the visitor operation
+   */
+  public <T> T accept(TreeNodeVisitor<T> visitor) {
+    return visitor.visit(this);
+  }
+
 }

core/src/org/sbml/jsbml/math/ASTCSymbolDelayNode.java

@@ -25,6 +25,7 @@
 import org.sbml.jsbml.ASTNode.Type;
 import org.sbml.jsbml.PropertyUndefinedError;
 import org.sbml.jsbml.SBMLException;
+import org.sbml.jsbml.TreeNodeVisitor;
 import org.sbml.jsbml.math.compiler.ASTNode2Compiler;
 import org.sbml.jsbml.math.compiler.ASTNode2Value;
 import org.sbml.jsbml.math.compiler.FormulaCompiler;
@@ -289,4 +290,15 @@ public String toMathML() {
     }
   }
 
+  /**
+   * Accepts a generic visitor to traverse this component.
+   *
+   * @param <T> the return type of the visitor
+   * @param visitor the visitor implementation
+   * @return the result of the visitor operation
+   */
+  public <T> T accept(TreeNodeVisitor<T> visitor) {
+    return visitor.visit(this);
+  }
+
 }

core/src/org/sbml/jsbml/math/ASTCSymbolTimeNode.java

@@ -25,6 +25,7 @@
 import org.sbml.jsbml.ASTNode.Type;
 import org.sbml.jsbml.PropertyUndefinedError;
 import org.sbml.jsbml.SBMLException;
+import org.sbml.jsbml.TreeNodeVisitor;
 import org.sbml.jsbml.math.compiler.ASTNode2Compiler;
 import org.sbml.jsbml.math.compiler.ASTNode2Value;
 import org.sbml.jsbml.math.compiler.FormulaCompiler;
@@ -313,4 +314,15 @@ public String toMathML() {
     }
   }
 
+  /**
+   * Accepts a generic visitor to traverse this component.
+   *
+   * @param <T> the return type of the visitor
+   * @param visitor the visitor implementation
+   * @return the result of the visitor operation
+   */
+  public <T> T accept(TreeNodeVisitor<T> visitor) {
+    return visitor.visit(this);
+  }
+
 }

core/src/org/sbml/jsbml/math/ASTCiFunctionNode.java

@@ -28,6 +28,7 @@
 import org.sbml.jsbml.Model;
 import org.sbml.jsbml.PropertyUndefinedError;
 import org.sbml.jsbml.SBMLException;
+import org.sbml.jsbml.TreeNodeVisitor;
 import org.sbml.jsbml.math.compiler.ASTNode2Compiler;
 import org.sbml.jsbml.math.compiler.ASTNode2Value;
 import org.sbml.jsbml.math.compiler.FormulaCompiler;
@@ -367,4 +368,15 @@ public String toMathML() {
     }
   }
 
+  /**
+   * Accepts a generic visitor to traverse this component.
+   *
+   * @param <T> the return type of the visitor
+   * @param visitor the visitor implementation
+   * @return the result of the visitor operation
+   */
+  public <T> T accept(TreeNodeVisitor<T> visitor) {
+    return visitor.visit(this);
+  }
+
 }

core/src/org/sbml/jsbml/math/ASTCiNumberNode.java

@@ -31,6 +31,7 @@
 import org.sbml.jsbml.PropertyUndefinedError;
 import org.sbml.jsbml.QuantityWithUnit;
 import org.sbml.jsbml.SBMLException;
+import org.sbml.jsbml.TreeNodeVisitor;
 import org.sbml.jsbml.math.compiler.ASTNode2Compiler;
 import org.sbml.jsbml.math.compiler.ASTNode2Value;
 import org.sbml.jsbml.math.compiler.FormulaCompiler;
@@ -383,4 +384,15 @@ public String toMathML() {
     }
   }
 
+  /**
+   * Accepts a generic visitor to traverse this component.
+   *
+   * @param <T> the return type of the visitor
+   * @param visitor the visitor implementation
+   * @return the result of the visitor operation
+   */
+  public <T> T accept(TreeNodeVisitor<T> visitor) {
+    return visitor.visit(this);
+  }
+
 }

core/src/org/sbml/jsbml/math/ASTCnNumberNode.java

@@ -26,6 +26,7 @@
 import org.sbml.jsbml.Model;
 import org.sbml.jsbml.PropertyUndefinedError;
 import org.sbml.jsbml.SBMLException;
+import org.sbml.jsbml.TreeNodeVisitor;
 import org.sbml.jsbml.Unit;
 import org.sbml.jsbml.UnitDefinition;
 import org.sbml.jsbml.math.compiler.ASTNode2Compiler;
@@ -388,4 +389,15 @@ public void unsetUnits() {
     firePropertyChange(TreeNodeChangeEvent.units, oldValue, null);
   }
 
+  /**
+   * Accepts a generic visitor to traverse this component.
+   *
+   * @param <T> the return type of the visitor
+   * @param visitor the visitor implementation
+   * @return the result of the visitor operation
+   */
+  public <T> T accept(TreeNodeVisitor<T> visitor) {
+    return visitor.visit(this);
+  }
+
 }

core/src/org/sbml/jsbml/math/ASTConstantNumber.java

@@ -24,6 +24,7 @@
 import org.sbml.jsbml.ASTNode.Type;
 import org.sbml.jsbml.PropertyUndefinedError;
 import org.sbml.jsbml.SBMLException;
+import org.sbml.jsbml.TreeNodeVisitor;
 import org.sbml.jsbml.math.compiler.ASTNode2Compiler;
 import org.sbml.jsbml.math.compiler.ASTNode2Value;
 import org.sbml.jsbml.math.compiler.FormulaCompiler;
@@ -219,4 +220,15 @@ public String toMathML() {
     }
   }
 
+  /**
+   * Accepts a generic visitor to traverse this component.
+   *
+   * @param <T> the return type of the visitor
+   * @param visitor the visitor implementation
+   * @return the result of the visitor operation
+   */
+  public <T> T accept(TreeNodeVisitor<T> visitor) {
+    return visitor.visit(this);
+  }
+
 }