Class which updates an object

Question

I have a class which updates an object. The class takes a String id in its constructor and returns the appropriate class based on the id. I think these two methods should be separated into their own classes as returning an object based on a String id will probably have uses elsewhere in the code base.

I've considered adding the functionality which returns the object to update into its own static method:

ObjectToUpdate = Utils.getObjectToUpdate(id)

Is there a better way or a design pattern?

UpdateContestantObj c = new UpdateContestantObj(childWithParentRatingsObject.getCoupleId());
c.getContestantObj().setSortVal(singleScoringFM.getScore());
c.persistContestant();

public class UpdateContestantObj {

    private String id;
    private ContestantObj contestantToSave = null;

    public ContestantObj getContestantObj(){
        return this.contestantToSave;
    }

    public UpdateContestantObj(String id){
        this.id = id;

        SimpleSortingVector simpleSortingVector = (SimpleSortingVector)FutureContent.future.getContent(Constants.CONTESTANTS_DATA);
        Enumeration contestantsEnumeration = simpleSortingVector.elements();

        while(contestantsEnumeration.hasMoreElements()){
            final ContestantButtonField contestantButtonField = (ContestantButtonField)contestantsEnumeration.nextElement();
            if(contestantButtonField.getContestant().getId().equalsIgnoreCase(this.id)){
                contestantToSave = contestantButtonField.getContestant();
            }
        }   
    }

    public void persistContestant(){

        contestantsStore.setContents(contestantToSave); 
        contestantsStore.commit();

    }
}

Answer 1

There's no super-design-pattern that would be beneficial here, but you could definitely benefit from some basic OO concepts like encapsulation and single responsibility.

For starters, rather than making a bunch of utility methods, it's better design to allow each class a static method like:

// inside the ContestantObj class
public static ContestantObj fromID(string ID) {
   // code to retrieve ContestantObj 
}

This way, each class is responsible for creating itself, which it should be (outside of cases where a builder or abstract factory is required).

Your UpdateContestantObj constructor should take in a ContestantObj. It shouldn't care about how the ContestantObj is created. A "Contestant Updater" should be a machine that takes in Contestants and outputs Contestants that have been updated.

Also, the naming convention of ContestantObj should simply be Contestant. We know it's an object.