Simplify numerous if, elseifs in java

Question

I am here to seek help w.rt. simplifying if-elseif statements in java. Here's my code below, which has numerous if, elseifs. Is it possible to simplify the below code using java lambda features? Can I reduce if, elseif statements in my method? Can we use Java 8 filter functionality here?

public ReturnsRetailerConfigPromotionResponse promoteRetailerConfig(
        ReturnsRetailerConfigPromotionRequest returnsRetailerConfigPromotionRequest,
        String configType) {
        try{
            if(isTenantConfigPromotion){
                tenantDetails = returnsGenericUtils.getTenantConfig(sourceRetailerName, sourceHubLoginResponse);
            }
            else if(isTrackConfigPromotion){
                returnsGenericUtils.downloadTrackConfig(sourceRetailerName, sourceHubcookies);
            }
            else if(isReturnRulesPromotion){
                returnsGenericUtils.downloadReturnRules(sourceRetailerName, sourceHubcookies);
            }
            else if(isReturnReasonsPromotion){
                returnsGenericUtils.downloadReturnReasons(sourceRetailerName, sourceHubcookies);
            }
        } catch (Exception e) {
            log.error(e.getMessage(), e);
            return new ReturnsRetailerConfigPromotionResponse(...);
        }
}

Answer 1

At first, I would remove redundant "else if" statements, if the only 'true' case is possible, like this:

            if(isTenantConfigPromotion){
                tenantDetails = returnsGenericUtils.getTenantConfig(sourceRetailerName, sourceHubLoginResponse);
            }
            if(isTrackConfigPromotion){
                returnsGenericUtils.downloadTrackConfig(sourceRetailerName, sourceHubcookies);
            }
            if(isReturnRulesPromotion){
                returnsGenericUtils.downloadReturnRules(sourceRetailerName, sourceHubcookies);
            }
            if(isReturnReasonsPromotion){
                returnsGenericUtils.downloadReturnReasons(sourceRetailerName, sourceHubcookies);
            }

And then I would think about moving the block somewhere else, cause` it looks like a side effect:

if(isTenantConfigPromotion){
  tenantDetails = ..
}

If you realy want to use lambdas here, than you can try to transform boolean conditions into text values, and make something like:

private static final Map<String, BiConsumer<Object, Object>> DOWNLOADERS_MAPPING = Map.of(
            "isTrackConfigPromotion", returnsGenericUtils::getTenantConfig,
            "isReturnRulesPromotion", returnsGenericUtils::downloadReturnRules,
            "isReturnReasonsPromotion", returnsGenericUtils::downloadReturnReasons
    );

public ReturnsRetailerConfigPromotionResponse promoteRetailerConfig(
            ReturnsRetailerConfigPromotionRequest returnsRetailerConfigPromotionRequest,
            String configType,
            Set<String> conditions
    ) {
        try {
            conditions.forEach(condition -> {
                DOWNLOADERS_MAPPING.getOrDefault(condition, returnsGenericUtils::doNothing).accept(sourceRetailerName, sourceHubcookies);
            });
        } catch (Exception e) {
            log.error(e.getMessage(), e);
            return new ReturnsRetailerConfigPromotionResponse(...);
        }
    }

than it's gonna be easier to extend the method if you get more conditions.