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https://issues.apache.org/jira/browse/WW-3750?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13232514#comment-13232514
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Lukasz Lenart edited comment on WW-3750 at 3/19/12 10:13 PM:
-------------------------------------------------------------
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, ${showConfig} expression will be evaluated only once throughout the
Stack and the returned value will always be the same.
{code:html}
<#list actionNames as name>
<@s.url id="showConfig" action="showConfig" includeParams="none">
<@s.param name="namespace">${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, ${showConfig} expression will be evaluated only once throughout the
Stack and the returned value will always be the same.
{code}
<#list actionNames as name>
<@s.url id="showConfig" action="showConfig" includeParams="none">
<@s.param name="namespace">${namespace}</@s.param>
<@s.param name="actionName">${name}</@s.param>
</@s.url>
<li><a href="${showConfig}">${name}</a></li>
</#list>
{code}
> 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.
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