LinkedList.java

class Node<T> {
    public T data;
    public Node<T> next;

    public Node(T val) {
        data = val;
        next = null;
    }
}

public class LinkedList<T> {
    private Node<T> head;
    private Node<T> current;

    public LinkedList() {
        head = current = null;
    }

    public boolean empty() {
        return head == null;
    }

    public boolean last() {
        return current.next == null;
    }

    public boolean isThereNext() {
        return current != null;
    }

    public boolean full() {
        return false;
    }

    public void findFirst() {
        current = head;
    }

    public void findNext() {
        current = current.next;
    }

    public boolean find(T val) {
        Node<T> tmp = head;
        if (tmp == null)
            return false;

        while (tmp != null) {
            boolean f = tmp.data == val;
            if (val.equals(tmp.data))
                return true;
            tmp = tmp.next;
        }
        return false;
    }

    public T retrieve() {
        return current.data;
    }

    public void update(T val) {
        current.data = val;
    }

    public void insert(T val) {
        Node<T> tmp;
        if (empty()) {
            current = head = new Node<T>(val);
        } else {
            tmp = current.next;
            current.next = new Node<T>(val);
            current = current.next;
            current.next = tmp;
        }
    }

    public void remove() {
        if (current == head) {
            head = head.next;
        } else {
            Node<T> tmp = head;
            while (tmp.next != current)
                tmp = tmp.next;
            tmp.next = current.next;
        }
        if (current.next == null)
            current = head;
        else
            current = current.next;
    }


    @Override
    public String toString() {
        String s = "[";
        for (Node<T> c = head; c != null; c = c.next) {
            s += c.data + " ";
        }
        return s + "]";
    }


}