双链表的Java手工实现

Question

我需要帮助为我的PerformanceList编写这个addAfterCurrent方法，它是一个双链表，声明了一个standerd head、tail和cursor（current）节点。节点类使用

PerformanceNode Next；PerformanceNode上一个；

public void addAfterCurrent(PerformanceNode element)
    {
        PerformanceNode temp = element;
        if (cursor == null)
        {
        head = temp;
        tail = temp;
        cursor = temp;
        }
        else
        {
            temp.setNext(cursor);
            cursor.setPrev(temp);

            cursor = temp;

            if(cursor == null)
            {
                tail = cursor;
            }
        }

    }

Answer 1

我根据定义用一些注释实现了：

public void addAfterCurrent(PerformanceNode node) {
    if (node == null)  {
        throw new IllegalArgumentException("Node to be added cannot be null!");
    }

    if (cursor == null && tail == null) {
        throw new IllegalStateException("There is neither current nor tail node!");
    }

    if (cursor == null) { // there is no current node
        // insert the node at the end of the list
        tail.setNext(node);
        node.setPrev(tail);

        // mode end cursor
        tail = node; 

        // current node should now be the newly created node
        cursor = node;
    } else { // there is current node
        PerformanceNode temp = cursor.getNext();

        // new node directly follows the current node 
        cursor.setNext(node);
        node.setPrev(cursor);

        if (temp != null) {
            node.setNext(temp);
            temp.setPrev(node);
        } else { // current node was the last node
            tail = node; // mode end cursor
        }
    }
}