简单的自定义有序的LinkedList

package thread.juc.linkedlist;


import java.util.NoSuchElementException;

/**
 * 简单的自定义 LinkedList
 * 有序的LinkedList
 */
public class SortLinkedList<E extends Comparable<E>> {

    private Node<E> head = null;

    private int size;

    public SortLinkedList() {
        head = null;
    }


    class Node<E extends Comparable<E>> {

        //Node<E> head;
        Node<E> next;
        E value;

        public Node(E value) {
            this.value = value;
        }

        public Node() {
        }
    }


    /**
     * 这里我们默认添加到头部,也可以添加到尾部
     */
    public void addFirst(E e) {

        Node<E> newNode = new Node<E>(e);
        Node<E> previous = null;
        Node<E> current = head;

        while (current != null && e.compareTo(current.value) > 0) {
            previous = current;
            current = current.next;
        }

        // 比第一个小
        if (previous == null) {
            head = newNode;
        } else {
            previous.next = newNode;
        }
        newNode.next = current;
        size++;
    }


    public Node<E> removeFirst() {

        if (size == 0) {
            throw new NoSuchElementException("linkList is empty ... ");
        }

        size--;

        //头部值
        Node<E> node = this.head;

        //头部指向下一个
        this.head = node.next;

        return node;
    }

    public boolean isEmpty() {
        return size == 0;
    }


    public String toString() {

        if (this.size == 0) {
            return "[]";
        }
        Node<E> node = head;

        StringBuilder builder = new StringBuilder("[");
        while (node != null) {
            System.out.println(node.value);
            builder.append(node.value).append(",");
            node = node.next;
        }

        String sb = builder.toString().substring(0, builder.length() - 1) + "]";

        return sb;
    }

    public int size() {
        return size;
    }

    public boolean contains(E e) {

        //第一个元素
        Node<E> head = this.head;

        while (head != null) {
            if (head.value.equals(e)) {
                return true;
            }
            head = head.next;
        }

        return false;
    }


    public static void main(String[] args) {

        SortLinkedList<Integer> list = new SortLinkedList<>();


        // 添加到前面
        list.addFirst(2);
        list.addFirst(-1);
        list.addFirst(-20);
        list.addFirst(200);
        list.addFirst(5);
        list.addFirst(7);


        System.out.println(list.isEmpty());
        System.out.println(list.size());
        System.out.println(list.toString());
        System.out.println(list.contains(1));
    }


}