CODEWITHSUNDEEP
javajavascript
Oliver Watkins
Oliver Watkins

Reputation: 13539

Flexible / Paramaterised Constructors in Java

I have been doing Java for 12 years, and I have recently been doing Javascript, and I was wondering if the Java community has considered some kind of flexible constructor mechanism.

Things can get messy with constructors in Java. If there are many different pathways to create an object, then you need a constructor for each.

What if you could have a constructor where you can put in whatever values you like that would match up with a classes internal field :

Person p = new Person([
  name:’bob’,
  height:123,
  address:new Address([
    street:’asdf’,
    postcode:4232
    ])
  ]);

(I am using square brackets here, but you would need some other symbol, as this would conflict with arrays in Java)

Then you define which fields in a class may be used in a constructor combination with an annotation :

public class Person{

    @constructable
    private String name;
    @constructable
    private int height;
    @constructable
    Private Address address;

.....

}       

public class Address {

    @constructable
    private String street;
    @constructable
    private String postcode;
    @constructable
    private String city;

.....

}

This would all be syntactic sugar. During compile time, the compiler would work out all the constructors that are needed for a class and update the class accordingly.

Has anything like this ever been proposed a JSR?

Does this break any core philosophy behind Java? (Ie. Constructors should not be so unrestrictive)

Upvotes: 0

Views: 330

Answers (1)

Puneet_Techie
Puneet_Techie

Reputation: 197

This can mostly be achieved by the Builder pattern. This is useful when there is a lot of information required to create the object.

Upvotes: 2

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