减少圈复杂度问题

Question

I have to fix sonar issue related to big cyclomatic complexity, but still haven't got any good idea how to do that.

The code consist of big amount of 'if' operators that are check parameters that came in method and decide which enum value to create

Here is a code snippet for example:

      public ProductType createProductType(String val1, String val2, String val3) {
        if (PRODUCT_MODEL.equals(val1) && PRODUCT_TYPE.equals(val2) {
            return ProductType.SOAP;
        }
        if (PRODUCT_MODEL.equals(val1) || val3.equals(SWAP)) {
            return ProductType.STRING;
        }
}

And so on.. As you can see I am not able to write this using switch case because there are more than 1 variable is checked. Also I can't create static map with keys of Predicate type because comparing criteria came to method dynamically. So I can't understand how to eliminate this 'if' operators.

Any suggestions?

EDIT

if divide it into methods for each product type how then I will check when the product type is created? I mean I have

ProductType productType = null;
productType = tryParseSoap;
if (Objects.nonNull(productType)) {
    return productType;
}
productType = tryParseString;
if (Objects.nonNull(productType)) {
    return productType
}

if do this I still have a lot of if cases for null-checking because without them suggest product created on the first check and then I will anyway check it a lot of times and this is a big productivity reducing

Answer 1

You could define an interface, say ProductTypeCreator

public interface ProductTypeCreator {

    boolean isApplicable(String val1, String val2, String val3);

    ProductType create(String val1, String val2, String val3);

}

Then, create an implementation for each specific if case. You could then have a List creators, and refactor your method to something like.

public ProductType createProductType(String val1, String val2, String val3) {
    // this should already be instantiated
    List<ProductTypeCreator> creators;
    return creators
       .stream()
       .filter(creator -> creator.isApplicable(val1, val2, val3))
       .map(creator -> creator.create(val1, val2, val3))
       .findFirst()
       .get();
}

In this way, you could avoid the ifs.

Hope this helps!