LinkedList

package it.uniupo.disit.se.lab01;

public class LinkedList {

    private NodeList head = null;

    public LinkedList() {

    }

    public LinkedList(String string) {
        if(!string.isEmpty()) {
            String[] array = string.split(" ");

            for(String element : array)
                addLast(Double.parseDouble(element));
        }
    }

    @Override
    public String toString() {
        StringBuilder result = new StringBuilder("[");
        NodeList current = head;

        while(current != null) {
            result.append(current.getValue()).append(" ");
            current = current.next();
        }

        return result.toString().trim() + "]";
    }

    public void addLast(double value) {
        if(head == null)
            head = new NodeList(value);
        else {
            NodeList current = head;
            while(current.next() != null)
                current = current.next();

            current.setNext(new NodeList(value));
        }
    }

    public void addFirst(double value) {
        if(head == null)
            head = new NodeList(value);
        else {
            NodeList current = new NodeList(value);
            current.setNext(head);
            head = current;
        }
    }

    public boolean removeFirst() {
        if(head == null)
            return false;

        head = head.next();
        return true;
    }

    public boolean removeLast() {
        if(head == null)
            return false;

        if(head.next() == null) {
            head = null;
            return true;
        }

        NodeList current = head;
        while(current.next().next() != null)
            current = current.next();

        current.setNext(null);
        return true;
    }

    public boolean remove(double value) {

        if(head != null) {
            if(head.getValue() == value) {
                head = head.next();
                return true;
            }

            NodeList current = head;
            while(current.next() != null) {
                if(current.next().getValue() == value) {
                    current.setNext(current.next().next());
                    return true;
                }
                current = current.next();
            }
        }
        return false;
    }

    public double mean() {
        if(head == null) return 0;

        double mean = 0, cnt = 0;

        NodeList current = head;
        while(current != null) {
            mean += current.getValue();
            cnt++;
            current = current.next();
        }

        return mean/cnt;
    }
}