条件文の簡略化

📌 条件文の分割

再包装前のソース

class Simple_Example{
	void Example(){
    	if(date < SUPPER_STAR || date > SUPPER_END)
        	charge = quantity * winterRate + winterServiceCharge;
        else
        	charge = quantity * summerRate;
    }
}

再包装したソース

class Simple_Example{
	void Example(){
    	if(isNotSummer())
        	charge = CalculateWinterRate();
        else
        	charge = CalculateSummerRate();
    }
}

private bool IsNotSummer(){
	return date < SUPPER_STAR || date > SUPPER_END;
}

private bool CalculateWinterRate(){
	return quantity * winterRate + winterServiceCharge;
}

private bool CalculateSummerRate(){
	return quantity * summerRate;
}

📌 冗長条件式の統合

再包装前のソース

if(anEmployee.seniority < 2) return 0;
if(anEmployee.MothsDisabled > 12) return 0;
if(anEmployee.isPartTime) return 0;

再包装したソース

if(isNotEligableForDisability()) return 0;

function isNotEligableForDisability(){
	return ((anEmployee.seniority < 2)
    		|| (anEmployee.MothsDisabled > 12)
            || (anEmployee.isPartTime));
}

📑 References