如何更改有序持久集合中的顺序？
我只需要更改（以前持久化的）有序集合中的项目顺序...
我尝试简单地将重新排列的集合传递给设置器：提交事务后，集合消失了。
然后我尝试clear()现有集合，然后addAll()：clear()使持久管理器将所有元素标记为已删除。 （但显然我希望能够在同一事务中使用集合项。）
（该集合不在默认提取组中，因此我也尝试了上述操作，并将指定的提取组添加到提取计划中。否运气。）
这一定是最愚蠢的问题，但我已经没有想法了，我已经被困在这里两天了。我发誓我用谷歌搜索过。 :(
I just need to change order of items in a (previously persisted) ordered collection...
I tried simply passing the re-arranged collection to a setter: after committing a transaction the collection is gone.
Then I tried to clear() the existing collection and addAll() afterwards: clear() makes persistent manager to mark all the elements as deleted. (But obviously I would like to be able to work with the collection items in the very transaction.)
(The collection is not in a default fetch group, so I tried the above also with the named fetch group added into the fetch plan. No luck.)
This must be the most stupid question, but I ran out of ideas and I'm stuck here two days already. I swear I googled. :(
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数据的顺序在索引中设置。不幸的是，当前不存在删除或重置索引的功能（如何删除 Google App Engine (Java) 中的索引？
不过，可以动态更改索引。 2010/03/dynamic-indexes-with-google-app-engine.html" rel="nofollow noreferrer">http://rahulshackyworld.blogspot.com/2010/03/dynamic-indexes-with-google-app-engine .html。
The order of the data is set in an index. Unfortunately, the functionality to delete or reset the index is not currently there (How-to delete indexes in Google App Engine (Java)?.
It may be possible to dynamically change the index, however. Take a look at http://rahulswackyworld.blogspot.com/2010/03/dynamic-indexes-with-google-app-engine.html.