[FIXED] Choose which methods to run, with user input

Issue

I have a list of methods within my class. And then want to have input string array, where the user can choose which methods they want to run. We are running expensive insurance calculations. And have over say eg 20 methods. Is there a way to conduct this without do an if check on each? maybe with reflection or interface?

@Override
public void ProductTest(ProductData productData, String[] methodNames)  {
  
    public void methodA(ProductData productData){...};
    public void methodB(ProductData productData){...};
    public void methodC(ProductData productData){...};
    public void methodD(ProductData productData){...};
    public void methodE(ProductData productData){...};
}

I am willing to change the Array into a different ObjectType if needed, to execute properly. Using SpringBoot, has it has a library of utility classes.

Solution

Use a Map<String, Consumer<ProductData>>, not separate method handles. Main reason - reflection is slow and dangerous when given user "input"

Use map.get(input).accept(product) to call it.

https://docs.oracle.com/javase/8/docs/api/index.html?java/util/function/Consumer.html

Example

Map<String, Consumer<ProductData>> map = new HashMap<>();

map.put("print_it", System.out::println);
map.put("print_id", data -> System.out.println(data.id));
map.put("id_to_hex", data -> {
  int id = data.getId();
  System.out.printf("0x%x%n", id);
});

ProductData data = new ProductData(16);
map.get("print_it").accept(data);
map.get("print_id").accept(data);
map.get("id_to_hex").accept(data);

Outputs

ProductData(id=16)
16
0x10

If you are planning on chaining consumers using andThen, you'd be better having an Optional<ProductData>, and using a Function<ProductData, ProductData> with Optional.map()

Answered By - OneCricketeer
Answer Checked By - Dawn Plyler (JavaFixing Volunteer)