Constructors with too many parameters

Question

Without giving too much away, I'm making an object which has 9 attributes. Let's use an RPG for example.

float strength, constitution, fortitude, dexterity, intelligence, charisma, wisdom, willpower, perception;

Given that the object is called player, the constructor of

public Player(float strength, float constitution, float fortitude, float dexterity, 
float intelligence, float charisma, float wisdom, float willpower, float perception){}

According to SonarLint: "Constructor has 9 parameters, which is greater than 7 authorized."

While I know that SonarLint saying that won't stop the code actually functioning, if there is a "proper" way of dealing with these situations, I'd love to know!

Thanks

P.s, if this is the wrong forum for such a question, please point me towards the right one!

https://stackoverflow.com/questions/58060511/optimization-in-constructor-parameters — Nosrep, Mar 29 '20 at 19:13
Thank you for the responses so far. I'll look up the Builder Pattern and 'EnumMaps' as suggested. After deciding which suits my situation the most, I'll accept the best answer! — MJDeveloping, Mar 29 '20 at 19:56
If you don't use an `EnumMap`, you'll regret it when you start to add more functionality to this class. — Dawood ibn Kareem, Mar 29 '20 at 20:34

score 1 · Answer 1 · answered Mar 29 '20 at 19:13

1

Try to use Builder Pattern, this method is very good for Classes with 4+ parameters.

answered Mar 29 '20 at 19:13

TomaszC283

17
6

Tom Hawtin - tackline · Accepted Answer · 2020-03-29T19:43:00.873

1

Ideally you would split the class into smaller units and compose.

In this case, as they seem to be all of the same kind of thing, a Map (specifically EnumMap) would appear to be appropriate.

As a last resort, there is the Builder Pattern.

 Player player = Player.builder()
     .strength(       )
     .constitution(   )
     // ...
     .perception(     );

edited Mar 29 '20 at 19:43

answered Mar 29 '20 at 19:17

Tom Hawtin - tackline

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An `EnumMap` is the best solution in this particular case. – Dawood ibn Kareem Mar 29 '20 at 20:33

score 0 · Answer 3 · answered Mar 29 '20 at 19:19

Try the builder pattern

final class Player {
  private final float strength;

  ...

  static final class Builder {
    private float strength;

    ...

    Builder setStrength(float strength) {
      this.strength = strength;
      return this;
    }

    ...

    Player build() {
      return new Player(this);
    }
  }

  private Player(Builder builder) {
    strength = builder.strength;
    ...
  }

  ...

  public static void main(String[] args) {
    Player player = new Player.Builder()
      .setStrength(18)
      .setConsitution(18)
      .setFortitude(18)
      .build();
   }
}

score 0 · Answer 4 · answered Mar 29 '20 at 19:20

0

It is never advisable and a proper way to define a function which has so many arguments.Ideally it should have 2 to 3 params only.In case where there are more then specified params then you can do any of the below things.

Create an class by wrapping up the paramameter(kind of logical grouping of params).
Use build patterns as specified above
Provide multiple constructor with only required params.
Use setter methods for few things, if you can certain parameters.

answered Mar 29 '20 at 19:20

Krutik Jayswal

3,165
1
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Read book named as clean code, it has so many things for proper coding techniques. – Krutik Jayswal Mar 29 '20 at 19:21
By Robert Cecil Martin? – MJDeveloping Mar 29 '20 at 19:56
@MJDeveloping Yes - [Uncle Bob](http://blog.cleancoder.com/). – andrewJames Mar 29 '20 at 20:20

Constructors with too many parameters

4 Answers4