PedestalledLeanLinkedList.java

public class PedestalledLeanLinkedList<T extends ContradictableType> {
    LinkedList<T> types = new LinkedList<>();

    public void insert(T type) {
        boolean first = true;
        for (Iterator<T> iterator = types.iterator(); iterator.hasNext(); ) {
            ContradictableType current = iterator.next();
            if (first) {
                first = false;
                continue;
            }
            if (current.equivalentTo(type)) {
                return;
            }

            if (current.cancelsOutWith(type)) {
                iterator.remove();
                return;
            }
        }

        types.add(type);
    }

    public T poll() {
        return types.pollFirst();
    }

    public T peek() {
        return types.peekFirst();
    }

    public boolean isEmpty() {
        return peek() == null;
    }
}