Java代码

1. public class LinkedListNode {
   //链表节点
2.  
3. public LinkedListNode previous;//前一节点
4. public LinkedListNode next;//后一节点
5. public Object object;//节点中存的值
6.  
7.  
8. public long timestamp;
9.  
10.  
11. public LinkedListNode(Object object, LinkedListNode next, LinkedListNode previous)
12. {
13. this.object = object;
14. this.next = next;
15. this.previous = previous;
16. }
17.  
18.  
19. public void remove() {
    //删除自己
20. previous.next = next;
21. next.previous = previous;
22. }
23.  
24.  
25. public String toString() {
26. return object.toString();
27. }
28. }
29.  
30. import java.util.*;
31.  
32.  
33. public class LinkedList {
    //循环链表
34.  
35. //头指针，哑的，第一个节点的前面，最后一个节点的后面
36. private LinkedListNode head = new LinkedListNode("head", null, null);
37.  
38.  
39. public LinkedList() {
40. head.next = head.previous = head;
41. }
42.  
43.  
44. public LinkedListNode getFirst() {
    //获取循环链表的第一个节点
45. LinkedListNode node = head.next;
46. if (node == head) {
47. return null;
48. }
49. return node;
50. }
51.  
52.  
53. public LinkedListNode getLast() {
    //获取循环链表的最后一个节点
54. LinkedListNode node = head.previous;
55. if (node == head) {
56. return null;
57. }
58. return node;
59. }
60.  
61.  
62. public LinkedListNode addFirst(LinkedListNode node) {
    //将节点插入到链表的第一个位置,头节点之后.
63. node.next = head.next;
64. node.previous = head;
65. node.previous.next = node;
66. node.next.previous = node;
67. return node;
68. }
69.  
70.  
71. public LinkedListNode addFirst(Object object) {
    //将值插入到链表的第一个位置,头节点之后.
72. LinkedListNode node = new LinkedListNode(object, head.next, head);
73. node.previous.next = node;
74. node.next.previous = node;
75. return node;
76. }
77.  
78. public LinkedListNode addLast(Object object) {
    //将值插入到链表的最后一个位置,头节点之前
79. LinkedListNode node = new LinkedListNode(object, head, head.previous);
80. node.previous.next = node;
81. node.next.previous = node;
82. return node;
83. }
84.  
85.  
86. public void clear() {
    //清空循环链表
87. //Remove all references in the list.
88. LinkedListNode node = getLast();
89. while (node != null) {
90. node.remove();
91. node = getLast();
92. }
93.  
94. //Re-initialize.
95. head.next = head.previous = head;
96. }
97.  
98. public String toString() {
99. LinkedListNode node = head.next;
100. StringBuffer buf = new StringBuffer();
101. while (node != head) {
102. buf.append(node.toString()).append(", ");
103. node = node.next;
104. }
105. return buf.toString();
106. }
107. }