CODEWITHSUNDEEP
javagenerics
Ankit
Ankit

Reputation: 3183

List iteration - Generic logic

I have a list of beans (List<AClass>), from which I am creating two sub list based some logic which involves checking a field from the bean class, say action. if 

bean.getAction.equals("true") - add to new sublist - List<AClass> listA
else - add to new sublist - List<AClass> listB

I have created a method for it and it works fine.

Now I have similar task for other Bean class as well where i have List<BClass> which also has action field and getAction method. I want to create a generic method which would cater to both these beans (and other similar beans as well).

How can I create such method?

Upvotes: 3

Views: 94

Answers (3)

OldCurmudgeon
OldCurmudgeon

Reputation: 65811

Something like this should work:

interface HasAction {
    public String getAction();
}

public class AClass implements HasAction {
    private final String action;

    public AClass (String action) {
        this.action = action;
    }

    @Override
    public String getAction() {
        return action;
    }

}
public class BClass implements HasAction {
    private final String action;

    public BClass (String action) {
        this.action = action;
    }

    @Override
    public String getAction() {
        return action;
    }

}

public <T extends HasAction> List<T> subList(List<T> list) {
    List<T> subList = new ArrayList<T> ();

    for ( T source : list ) {
        if ( source.getAction().equals("true")) {
            subList.add(source);
        }
    }
    return subList;
}

Upvotes: 1

Reimeus
Reimeus

Reputation: 159754

If AClass and BClass share a common base then a wilcard type can be used - List<? extends CommonBase>

Upvotes: 3

luboskrnac
luboskrnac

Reputation: 24561

Use List<? extends ParentClass> where ParentClass is parent of AClass and BClass

Upvotes: 3

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