How to use NashornSandbox in safe way

Question

I am using the following code to execute the statements

NashornSandbox sandbox = NashornSandboxes.create();

         String input = "(20>=10 && 19<=20 || 33>30 ) &&  233>30";
          try {
                // Evaluate the logical expression
                Object result = sandbox.eval(input);

                if (result instanceof Boolean) {
                    boolean booleanResult = (boolean) result;
                    System.out.println("Result: " + booleanResult);
                } else {
                    System.out.println("Invalid expression: Result is not a boolean");
                }
            } catch (ScriptException e) {
                System.out.println("Invalid expression: " + e.getMessage());
            }

how to only allow execute logic expressions and prevent while,for,exist and everything else.