Increase cognitive complexity on recursion

pmd-apex/src/main/java/net/sourceforge/pmd/lang/apex/metrics/impl/visitors/CognitiveComplexityVisitor.java

@@ -11,7 +11,9 @@ public class CognitiveComplexityVisitor extends ApexParserVisitorAdapter {
     public static class State {
         private int complexity = 0;
         private int nestingLevel = 0;
+
         private BooleanOp currentBooleanOperation = null;
+        private String methodName = null;
 
         public double getComplexity() {
             return complexity;
@@ -44,6 +46,16 @@ public class CognitiveComplexityVisitor extends ApexParserVisitorAdapter {
         void decreaseNestingLevel() {
             nestingLevel--;
         }
+
+        void methodCall(String methodCalledName) {
+            if (methodCalledName.equals(methodName)) {
+                structureComplexity();
+            }
+        }
+
+        void setMethodName(String name) {
+            methodName = name;
+        }
     }
 
     @Override
@@ -185,4 +197,18 @@ public class CognitiveComplexityVisitor extends ApexParserVisitorAdapter {
 
         return data;
     }
+
+    @Override
+    public Object visit(ASTMethod node, Object data) {
+        State state = (State) data;
+        state.setMethodName(node.getNode().getMethodInfo().getCanonicalName());
+        return super.visit(node, data);
+    }
+
+    @Override
+    public Object visit(ASTMethodCallExpression node, Object data) {
+        State state = (State) data;
+        state.methodCall(node.getNode().getMethodName());
+        return super.visit(node, data);
+    }
 }

pmd-apex/src/test/resources/net/sourceforge/pmd/lang/apex/metrics/impl/xml/CognitiveComplexityTest.xml

@@ -338,4 +338,25 @@
             ]]>
         </code>
     </test-code>
+
+    <test-code>
+        <description>Recursion bumps complexity value</description>
+        <expected-problems>1</expected-problems>
+        <expected-messages>
+            <message>'c__Foo#foo(Integer)' has value 3.</message>
+        </expected-messages>
+        <code>
+            <![CDATA[
+            class Foo {
+              Integer foo(Integer n) {
+                if (n == 0 || n == 1) { // +2
+                  return 1;
+                }
+
+                return n * foo(n - 1); // +1
+              }
+            }
+            ]]>
+        </code>
+    </test-code>
 </test-data>