Java Iterator backed by a ResultSet

Question

I\'ve got a class that implements Iterator with a ResultSet as a data member. Essentially the class looks like this:

public class A implements Iterator{
            


        

Answer 1

You could try the following:

public class A implements Iterator {
    private ResultSet entities;
    private Entity nextEntity;
    ...
    public Object next() {
        Entity tempEntity;
        if ( !nextEntity ) {
            entities.next();
            tempEntity = new Entity( entities.getString...etc....)
        } else {
            tempEntity = nextEntity;
        }

        entities.next();
        nextEntity = new Entity( entities.getString...ext....)

        return tempEntity;
    }

    public boolean hasNext() {
        return nextEntity ? true : false;
    }
}

This code caches the next entity, and hasNext() returns true, if the cached entity is valid, otherwise it returns false.