package listFW.visitor;

import listFW.*;

/**
 * Sums the elements in the host list by using a helper algorithm when the host
 * list is not empty.
 * @author DXN
 */
public class GetSum implements IListAlgo {
    public Object emptyCase(IEmptyList host, Object inp) {
        return new Integer(0);
    }

    /**
     * Passes the host's first to the rest and asks for help to compute the sum.
     */
    public Object nonEmptyCase(INEList host, Object inp) {
        return host.getRest().execute(new HelpGetSum(), host.getFirst());
    }
}