[jira] [Issue Comment Edited] (WW-3750) ScopesHashModel calls OgnlValueStack.findValue too many times during rendering freemarker templates

["Lukasz Lenart (Issue Comment Edited) (JIRA)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/WW-3750?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13232514#comment-13232514 ] 

Lukasz Lenart edited comment on WW-3750 at 3/19/12 9:27 AM:
------------------------------------------------------------

This patch has a side effect on how <#list> (<#foreach> and so one) are working in Freemarker templates.

Take a look on the exercise below from the config-browser plugin. With patch in place, ${showConfig} expression will be evaluated only once throughout the Stack and the returned value will always be the same.

{code}
<#list actionNames as name>
    <@s.url id="showConfig" action="showConfig" includeParams="none">
        <@s.param name="namespace">${namespace}</...@s.param>
        <@s.param name="actionName">${name}</...@s.param>
    </...@s.url>
    <li><a href="${showConfig}">${name}</a></li>
</#list>
{code}
                
      was (Author: lukaszlenart):
    This patch has a side effect on how <#list> (<#foreach> and so one) are working in Freemarker templates.

Take a look on the exercise below from the config-browser plugin. With patch in place, ${showConfig} expression will be evaluated only once throughout the Stack.
{code}
<#list actionNames as name>
    <@s.url id="showConfig" action="showConfig" includeParams="none">
        <@s.param name="namespace">${namespace}</...@s.param>
        <@s.param name="actionName">${name}</...@s.param>
    </...@s.url>
    <li><a href="${showConfig}">${name}</a></li>
</#list>
{code}


                  
> ScopesHashModel calls OgnlValueStack.findValue too many times during rendering freemarker templates
> ---------------------------------------------------------------------------------------------------
>
>                 Key: WW-3750
>                 URL: https://issues.apache.org/jira/browse/WW-3750
>             Project: Struts 2
>          Issue Type: Improvement
>          Components: Value Stack
>    Affects Versions: 2.3.1.1
>            Reporter: Pelladi Gabor
>            Assignee: Johannes Geppert
>            Priority: Minor
>              Labels: patch, performance
>             Fix For: 2.3.2
>
>         Attachments: WW-3750-2.diff, WW-3750.diff
>
>
> I saw using a profiler, that OgnlValueStack.findValue(String) gets called about a thousand times during rendering a page. Most of the calls are coming from ScopesHashModel.
> All freemarker templates contain a lot of references to e.g. "parameters". This variable is evaluated in ScopesHashModel over and over again, which takes about 10% time of total page load.
> I think we can assume, that the top-level objects on the value stack will not change during rendering a single struts2 tag. So with a little caching, we can eliminate most of the findValue method calls.
> In my application I tested this modification and didn't notice any side effects or bugs. The OgnlValueStack.findValue(String) calls on a test page went down from a thousand to a hundred. This improved overall page rendering time from about 400ms to 360ms.
> Patch is attached.
> Please review it.

--
This message is automatically generated by JIRA.
If you think it was sent incorrectly, please contact your JIRA administrators: https://issues.apache.org/jira/secure/ContactAdministrators!default.jspa
For more information on JIRA, see: http://www.atlassian.com/software/jira