package listFW.visitor;

import listFW.*;

/**
 * Checks to see if the host list contains all non-negative integers.
 * @author DXN
 */
public class CheckAllNonNegative implements IListAlgo {

    public Object emptyCase(IEmptyList host, Object inp) {
        return Boolean.TRUE;
    }

    public Object nonEmptyCase(INEList host, Object inp) {
        int f = ((Integer)host.getFirst()).intValue();
        return new Boolean(0 <= f && ((Boolean)host.getRest().execute(this, null)).booleanValue());
    }
}