[jira] Commented: (WW-2807) Improve Velocity tag syntax and performance

["Musachy Barroso (JIRA)" <ji...@apache.org>]

    [ https://issues.apache.org/struts/browse/WW-2807?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=45746#action_45746 ] 

Musachy Barroso commented on WW-2807:
-------------------------------------

Hi Christopher, did you ever got the patch done? 

> Improve Velocity tag syntax and performance
> -------------------------------------------
>
>                 Key: WW-2807
>                 URL: https://issues.apache.org/struts/browse/WW-2807
>             Project: Struts 2
>          Issue Type: Improvement
>    Affects Versions: 2.0.0, 2.0.1, 2.0.2, 2.0.3, 2.0.4, 2.0.5, 2.0.6, 2.0.7, 2.0.8, 2.0.9, 2.0.10, 2.0.11, 2.0.11.1, 2.0.11.2, 2.0.12, 2.1.0, 2.1.1, 2.1.2, 2.1.3, 2.1.4, 2.2.x, Future
>         Environment: Apache Velocity 1.5+
>            Reporter: Christopher Schultz
>            Priority: Minor
>             Fix For: 2.1.7
>
>
> Currently, Velocity "tags" are implemented by passing a number of "name=value" strings to S2's Velocity tag implementation in order to pass named parameters (which are not directly supported by Velocity). This leads to a somewhat awkward syntax and requires that the tag implementation re-parse these strings for every template evaluation, loop execution, etc.
> Starting with Velocity 1.5, template authors can create Map objects on the fly using a simple syntax. I believe that supporting this syntax in the Velocity S2 integration code will make templates easier to read and run more quickly.
> Example of current Velocity tag usage (this is the example  from http://struts.apache.org/2.0.11.2/docs/velocity-tags.html):
> #sform ("action=updatePerson")
>     #stextfield ("label=First name" "name=firstName")
>     #ssubmit ("value=Update")
> #end
> The new, proposed syntax would be this:
> #sform({'action' : 'updatePerson' })
>   #stextfield({'label' : 'First name', 'name' : 'firstName'})
>   #ssubmit({'value' = 'Update'})
> #end
> The tag implementation has change from supporting an unknown number of unnamed string parameters to accepting a single Map parameter containing name/value pairs. S2's code will no longer hand to parse each of the string parameters into their separate name and value, and should therefore run faster.
> It also allows template designers to use single-quote syntax for their parameter names (single-quoted strings are never interpreted) and either double-quote syntax for their values (which /will/ interpret their contents) or pass the objects directly (possibly as non-String objects). I believe this will also increase performance as well as flexibility, since some tags will prefer non-String parameters and will no longer be required to parse a String unless absolutely necessary.
> Such a change would require one of the following strategies:
> 1. Implement a second Velocity tag library whose tags accept a single Map parameter
> 2. Augment the current Velocity tag library to accept /either/ a single Map parameter /or/ a series of String values
> I believe #2 would be a better solution: users can choose which syntax they prefer and don't have to go through any messy re-configuration steps to switch syntax. It also supports legacy users with no changes at all. The only downside is that you'd have to restrict any future tags such that they do not accept a single Map parameter and then behave differently. I think this is a reasonable trade-off.
> I would be happy to submit a sample implementation for one or two tags, but I'll probably need help doing /every/ tag.
> Thanks,
> -chris
> Please see the following mailing list threads for reference:
> [struts-dev] http://www.nabble.com/-s2--Improved-Velocity-Integration-td19541213.html
> [struts-user] http://www.nabble.com/-S2--Velocity-Integration-td19520425.html
> [velocity-dev] http://www.nabble.com/Named-macro-parameters-td19459070.html

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