Question

What is the best (most compact) way to hand this situation:
One or more arguments to a method call depends on some condition, while the rest of the arguments are identical?

For example– you want to

DeathRay mynewWpn = new DeathRay(particle.proton, chassisColor.BLACK, oem.ACME)

if

enemy_composition == nature.ANTIMATTER

but

DeathRay mynewWpn = new DeathRay(particle.anti-proton, chassisColor.BLACK, oem.ACME)

if

enemy_composition == nature.MATTER

Obviously you can if-else but it looks unnecessarily long when there are a lot of arguments or more than one conditional argument. I have also done this creating an argument with an if-else beforehand and then calling the method. Again, that seems kind of clunky. Is there some sort of inline syntax similar to an Excel if-statement?

Answer 1

You can do

new DeathRay(enemy_composition == nature.ANTIMATTER ? particle.proton : particle.anti-proton, chassisColor.BLACK, oem.ACME)

… but I think we can all agree that’s hideous. It also assumes that there are only two kinds of particle.

Here are some better alternatives.

switch:

particle type;
switch (enemy_composition) { /* Assuming "nature" is an enum. */
  case ANTIMATTER : 
    type = particle.proton;
    break;
  case MATTER : 
    type = particle.antiproton;
    break;
}
DeathRay mynewWpn = new DeathRay(type, chassisColor.BLACK, oem.ACME);

enum method:

Add a method to your enum, Nature.

public enum Nature
{

  MATTER
  {
    public Particle getCounterWeapon()
    {
      return Particle.ANTIPROTON;
    }
  },
  ANTIMATTER
  {
    public Particle getCounterWeapon()
    {
      return Particle.PROTON;
    }
  };

  public abstract Particle getCounterWeapon();

}

Then use it.

DeathRay mynewWpn = new DeathRay(enemy_composition.getCounterWeapon(), chassisColor.BLACK, oem.ACME);

Map:

particle type = counterWeapons.get(enemy_composition);
DeathRay mynewWpn = new DeathRay(type, chassisColor.BLACK, oem.ACME);