code: protected void addViolation(MethodNode node, String message) {
          addViolation((ASTNode) node, String.format(
                  "Violation in class %s. %s", node.getDeclaringClass().getNameWithoutPackage(), message
          ));
      }
docs: Add a new Violation to the list of violations found by this visitor.
  Only add the violation if the node lineNumber >= 0.
  
  @param node    - the Groovy AST Node
  @param message - the message for the violation; defaults to null