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Posted to commits@wicket.apache.org by "Carl-Eric Menzel (JIRA)" <ji...@apache.org> on 2012/05/06 18:43:50 UTC
[jira] [Commented] (WICKET-4524) ListMultipleChoice has a
performance issue with very large lists, patch included
[ https://issues.apache.org/jira/browse/WICKET-4524?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13269254#comment-13269254 ]
Carl-Eric Menzel commented on WICKET-4524:
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I agree with the general sentiment here, but there's a problem: The list of choices is not necessarily static, it could also be a model with changing contents. This would be broken by generating a one-time hashmap snapshot.
Instead, I propose adding a FixedChoicesListMultipleChoice component that extends LMC explicitly for this situation and so can use a map to cache the IDs. Be aware of possibly high memory use though!
> ListMultipleChoice has a performance issue with very large lists, patch included
> --------------------------------------------------------------------------------
>
> Key: WICKET-4524
> URL: https://issues.apache.org/jira/browse/WICKET-4524
> Project: Wicket
> Issue Type: Improvement
> Components: wicket
> Affects Versions: 1.4.20
> Reporter: Martin Makundi
> Priority: Minor
> Labels: performance
> Attachments: patch.txt
>
> Original Estimate: 0.25h
> Remaining Estimate: 0.25h
>
> If ListMultipleChoice has thousands of options, the convertChoiceIdsToChoices method will become a performance bottleneck because it has a O(N^2) algorithm for determining the selected items. This patch suggests an optimization using a HashMap which will have a performance improvement in cases of large choices lists (users typically 'select all' in such situation).
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