superclass vs utility class for common code

Question

I have the same method in 2 classes that copy fields from one object to builders. I want to refactor it but I do not know if I should create a static method in an utility class or abstract it to a superclass.

The classes that shares this code are Beans and part of a multithreading app.

The method would be like:

protected static void copyPartyGroup(Message.Builder msgBuilder, 
    final PartyGroup partyIDsGroup, Party.Builder rartyBuilder) {

    rartyBuilder.setPartyID(partyIDsGroup.getId())
    ....

    msgBuilder.setID(partyIDsGroup.getId())

    ....

}

Thank you very much for your help.

François LEPORCQ · Accepted Answer · 2017-09-28T11:48:28.763

You can also use a trait in java 8, It's an interface with default methods

see : https://opencredo.com/traits-java-8-default-methods/

or : https://dzone.com/articles/using-traits-in-java-8

If your two classes not share a same parent structure, don't use a super abstract class, if the only reason to create this super class is to share your method copyPartyGroup is not a good practice.

see : Liskov substitution principle

If you want to respect the Single Responsability Principle:

I think you have to create a service class. In your case, maybe a threadsafe singleton with syncronized methods for rartyBuilder.setPartyID and msgBuilder.setID. (see Initialization-on-demand holder idiom)

hi, your images have dead. Would you mind to update them? – Boooooooooms Aug 19 '20 at 17:09 — Boooooooooms, Aug 19 '20 at 17:09

score 1 · Answer 2 · answered Sep 29 '17 at 18:35

1

If you can extract a static method, then it is better to just do that.

Using inheritance to share code couples your code and makes it really hard to untangle later.

answered Sep 29 '17 at 18:35

JnRouvignac

807
5
19

superclass vs utility class for common code

2 Answers2