| 1042 |
|
} |
| 1043 |
|
|
| 1044 |
|
/** |
| 1045 |
+ |
* Returns the successor node of the given non-null, but |
| 1046 |
+ |
* possibly previously deleted, node. |
| 1047 |
+ |
*/ |
| 1048 |
+ |
private Node<E> succ(Node<E> n) { |
| 1049 |
+ |
// Chains of deleted nodes ending in null or self-links |
| 1050 |
+ |
// are possible if multiple interior nodes are removed. |
| 1051 |
+ |
for (;;) { |
| 1052 |
+ |
Node<E> s = nextNode(n); |
| 1053 |
+ |
if (s == null) |
| 1054 |
+ |
return null; |
| 1055 |
+ |
else if (s.item != null) |
| 1056 |
+ |
return s; |
| 1057 |
+ |
else if (s == n) |
| 1058 |
+ |
return firstNode(); |
| 1059 |
+ |
else |
| 1060 |
+ |
n = s; |
| 1061 |
+ |
} |
| 1062 |
+ |
} |
| 1063 |
+ |
|
| 1064 |
+ |
/** |
| 1065 |
|
* Advances next. |
| 1066 |
|
*/ |
| 1067 |
|
void advance() { |
| 1069 |
|
lock.lock(); |
| 1070 |
|
try { |
| 1071 |
|
// assert next != null; |
| 1072 |
< |
Node<E> s = nextNode(next); |
| 1053 |
< |
if (s == next) { |
| 1054 |
< |
next = firstNode(); |
| 1055 |
< |
} else { |
| 1056 |
< |
// Skip over removed nodes. |
| 1057 |
< |
// May be necessary if multiple interior Nodes are removed. |
| 1058 |
< |
while (s != null && s.item == null) |
| 1059 |
< |
s = nextNode(s); |
| 1060 |
< |
next = s; |
| 1061 |
< |
} |
| 1072 |
> |
next = succ(next); |
| 1073 |
|
nextItem = (next == null) ? null : next.item; |
| 1074 |
|
} finally { |
| 1075 |
|
lock.unlock(); |
