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1
2 package SOFA.SOFAnode.Made.CDL;
3
4 class ListItem {
5 public Object  item;
6 public ListItem prev;
7 public ListItem next;
8 public ListItem(Object what, ListItem prv, ListItem nxt) {
9 item = what;
10 prev = prv;
11 next = nxt;
12 }
13 }
14
15 class List {
16 int count;
17 ListItem first;
18 ListItem last;
19 ListItem akt;
20
21 public List() {
22 count = 0;
23 first = null;
24 last = null;
25 akt = null;
26 }
27
28 void add(Object what) {
29 ListItem li;
30 if (count==0) {
31 li = new ListItem(what, null, null);
32 first = li;
33 last = li;
34 akt = first;
35 } else {
36 li = new ListItem(what, last, null);
37 last.next = li;
38 last = li;
39 }
40 count++;
41 }
42
43 void prepend(Object what) {
44 ListItem li;
45 if (count==0) {
46 li = new ListItem(what, null, null);
47 first = li;
48 last = li;
49 akt = first;
50 } else {
51 li = new ListItem(what, null, first);
52 first.prev = li;
53 first = li;
54 }
55 count++;
56 }
57
58 public int size() { return count; }
59
60 public Object aktual() {
61 if (akt==null)
62 return null;
63 return akt.item;
64 }
65
66 public boolean toNext() {
67 if (akt.next==null)
68 return false;
69 else akt = akt.next;
70 return true;
71 }
72
73 public boolean toPrev() {
74 if (akt.prev==null)
75 return false;
76 else akt = akt.prev;
77 return true;
78 }
79
80 public void toFirst() { akt = first; }
81
82 public void toLast() {akt = last; }
83
84 public Object removeAkt() {
85 if (count>0) {
86 Object ret = akt.item;
87 if (count==1) {
88 akt = first = last = null;
89 count = 0;
90 } else {
91 if (akt == first) {
92 first = akt.next;
93 first.prev = null;
94 akt.next = null;
95 akt = first;
96 } else {
97 if (last == akt) {
98 last = akt.prev;
99 last.next = null;
100 akt.prev = null;
101 akt = last;
102 } else {
103 akt.prev.next = akt.next;
104 akt.next.prev = akt.prev;
105 akt = akt.next;
106 }
107 }
108 count--;
109 }
110 return ret;
111 }
112 return null;
113 }
114 }
115 |
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