package filter_ws12;

public class List<T> {
	private final T info;
	private final List<T> next;

	public List(T info, List<T> next) {
		this.info = info;
		this.next = next;
	}
	
	static <S> List<S> filter (List<S> node , Predicate<S> pred ) {
		if (node == null)
			return null;
		
		S contentFirst = node.info;
		List<S> rest = node.next;
		
		List<S> filtered = filter(rest, pred);
		
		if (pred.applies(contentFirst)) {
			 return new List<>(contentFirst, filtered);
		} else {
			return filtered;
		}
	}
	
}