public class DoublyList { public DoubleNode head; public DoublyList() { this.head = new DoubleNode(); this.head.prev = null; this.head.next = null; } public String toString() { Stri...-Go服务器开发

修改后的代码如下所示：

public class DoublyList<T> {
    public DoubleNode<T> head;

    public DoublyList() {
        this.head = new DoubleNode<>();
        this.head.prev = null;
        this.head.next = null;
    }

    public String toString() {
        if (this.head.next == null) {
            return this.getClass().getName() + "()";
        }
        
        StringBuilder str = new StringBuilder();
        str.append(this.getClass().getName()).append("(");

        DoubleNode<T> p = this.head.next;
        
        while (p != null && p != this.head) {
            str.append(p.data.toString());
            
            if (p.next != null && p.next != this.head) {
                str.append(", ");
            }
            
            p = p.next;
        }

        return str.append(")").toString();
    }

    public void insert(T x) {
        if (x == null) {
            return;
        }

        DoubleNode<T> newNode = new DoubleNode<>(x, this.head.prev, this.head);
        
        if (this.head.prev != null) {
            this.head.prev.next = newNode;
        }
        
        this.head.prev = newNode;
        
        if (this.head.next == null) {
            // List is empty
            this.head.next = newNode;
        }
    }

    public void concat(DoublyList<T> list) {
    	if (list == null || list.isEmpty()) {
    		return;
    	}
    	
    	if (isEmpty()) {
    		this.head.next = list.head.next;
    		this.head.prev = list.tail();
    		
    		if (list.tail() != null) {
    			list.tail().next = head;
    		}
    		
    	} else {    	
	        DoubleNode<T> tail1 = tail();
	        DoubleNode<T> head2 = list.head.next;
	        
	        tail1.next = head2;
	        
	        if (head2 != null) {
	        	head2.prev = tail1;
	        }
	        
	        this.head.prev = list.tail();
	        
	        if (list.tail() != null) {
	        	list.tail().next = head;
	        }
    	}
    	
        list.head.next = null;
    }

    public void addAll(DoublyList<T> list) {
        concat(list);
    }

    public DoublyList<T> union(DoublyList<T> list) {
        DoublyList<T> result = new DoublyList<>();
        result.concat(this);
        result.addAll(list);
        return result;
    }

    private boolean isEmpty() {
        return this.head.next == null;
    }
    
    private DoubleNode<T> tail() {
    	DoubleNode<T> p = this.head.next;
    	
    	while (p != null && p.next != this.head) {
    		p = p.next;
    	}
    	
    	return p;
    }

    public static void main(String[] args) {
        DoublyList<Integer> list1 = new DoublyList<>();
        DoublyList<Integer> list2 = new DoublyList<>();
        
        for (int i = 1; i <= 5; i++) {
            list1.insert(i);
        }
        
        for (int i = 6; i <= 10; i++) {
            list2.insert(i);
        }
        
        System.out.println(list1.toString());
        System.out.println(list2.toString());
        
        list1.addAll(list2);
        
        System.out.println(list1.toString());
    }
}

在这个修改后的代码中，我们使用了 DoubleNode 类表示双链表节点。同时，我们添加了方法来处理循环双链表的操作，包括插入元素、连接两个循环双链表、合并两个循环双链表以及将一个循环双链表添加到当前列表中。在 toString 方法中，我们修改了输出格式，确保可以正确地打印出循环双链表的内容。

最后，在 main 方法中，我们创建了两个循环双链表，并进行了一些操作来验证代码的正确性。

内容由零声教学AI助手提供，问题来源于学员提问