[jira] [Commented] (MYFACES-3130) [PERF] Avoid unnecessary AbstractList$Itr instances

["Martin Kočí (JIRA)" <de...@myfaces.apache.org>]

    [ https://issues.apache.org/jira/browse/MYFACES-3130?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13031945#comment-13031945 ] 

Martin Kočí commented on MYFACES-3130:
--------------------------------------

mail topic: [core] performance: use indices instead of iterator (MYFACES-3130)

http://www.mail-archive.com/dev@myfaces.apache.org/msg52979.html

> [PERF] Avoid unnecessary AbstractList$Itr instances
> ---------------------------------------------------
>
>                 Key: MYFACES-3130
>                 URL: https://issues.apache.org/jira/browse/MYFACES-3130
>             Project: MyFaces Core
>          Issue Type: Improvement
>          Components: JSR-314
>         Environment: myfaces core trunk
>            Reporter: Martin Kočí
>         Attachments: MYFACES-3130-example.patch
>
>
> Similar issue: MYFACES-3129
> loop from java 5:
> for (Object object: objects)
> creates new instance of AbstractList$Itr, if objects are instance of ArrayList. 
> Similar situation is with explicit .iterator() call.
> In my testcases, it is about ~ 100 000 instances per request/response. Creation itself is cheap, but triggers GC lately.
> I suggest to use old index-style for (i = 0; i < childCount;   i++) if possible. Are there any rawbacks of index-based iteration? 
> Children is List and as implementation detail we  know that it is instance of ArrayList.

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