Question

let’s say I have a class that does some calculations. This set of calculations requires as an input a set of parameters.

public class Calculator
{
private CalculatorConfig _config;
public Calculator(CalculatorConfig config)
{
_config = config;
}

public Result Calculate(object obj){}
}

My CalculatorConfig class is very simple :

public class CalculatorConfig
{
      public double param1;
      public double param2;
      ...
}

and I initialize it very simply

var config = new CalculatorConfig();
config.param1 = val;
....
var calculator = new Calculator(config);

The dilema I have is that user of this class may forget to initialize some of the fields which may lead to weird behaviour.
Solution that may make a sense would be to convert fields into properties and for each private field have an extra boolean that would hold the information whether the field was initialized.
I can also create a megaconstructor, that would have all the fields as arguments.

What approach would you choose in this case?

Thanks

Answer 1

I will use another approach.

• Add another method (perhaps an internal method) called Check to your CalculatorConfig class.
• Call this method inside the execution of the Calculate method.

• In the Check method verify each parameter and throw a custom
  exception is something is wrong

  public class CalculatorConfig 
  { 
    public double param1; 
    public double param2; 
    ... 
    internal void Check()
    {
         if(param1 == 0.0)
             throw new ArgumentException("Configuration error: param1 is not valid!");
         if(param2 == 0.0)
             throw new ArgumentException("Configuration error: param2 is not valid!");
         .... // other internal checks
    }
  } 
  
  
  public class Calculator 
  { 
      private CalculatorConfig _config; 
      public Calculator(CalculatorConfig config) 
      { 
          _config = config; 
      } 
  
      public Result Calculate(object obj)
      {
          // Throw ArgumentException if the configuration is not valid
          // Will be responsability of our caller to catch the exception
          _config.Check();
  
          // Do your calcs
          .....
      } 
  }