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To access Webworkthe ValueStack from third -party JSP taglibs you have to, expose property values to JSP.

You canusing use Webwork2 tag <ww:set/> to set named parameter in a JSP page, request, session or application scope. Following  example, sets the {{<saf:set}} tag.

{code:xml:title=Set a request scoped parameter 'a' to list of integers:

{code:xml}
<ww<saf:set name="'a'" value="{ 1, 2, 3, 4 }" scope="request"/>
{code}

After setting parameterparameters, third -party JSP taglibs can access variables, or you can use JSP 2.0 EL (Expression Language). This is convenient as short hand EL expression syntax 
{{$

{expression}
}}
{{}}

 can be used in a text or inside of tag attributes: 

{code:xml}
a[0] = ${a[0]}

<sample:tag value="${a[1]}"/>
{code}

In practice, you've got to expose a lot of different variables to make effective use of third party taglibs like displaytag or wurfl. This leads to a lot of {{<ww:set/>}} tags what made me investigate how to make access to ValueStack and OGNL more transparent.

{note:title=Why can't we just replace EL with OGNL?}
Unfortunately, it isn't that simple. I've tinkered with {{JSPFactory.setDefault()}} to wrap around {{getPageContext()}} and create {{ExpressionEvaluator}} that would use OGNL. 

This works in practice, but code generated by Jasper2 doesn't call {{JSPFactory.getPageContext().getExpressionEvaluator()}} but goes directly to static method that is hardwired to jakartaJakarta commonsCommons-elEL implementation.

Even if it would work it wouldn't be _clean_ as {{JSPFactory.setDefault()}} should only be called by JSP implementation.
{note}

There is a simple, if not elegant, solution available in JSP 2.0 EL, for exposing ValueStack to OGNL. It is possible to create custom functions that can be called from EL expressions. Functions have to be 'public static' and specified in a TLD file. 
Just
To use a function, import the TLD in a JSP file where you've want to use a function. 

For example, you could access actionAction properties by evaluating OGNL expression by a function 'vs' (for valuestack) in EL:.

{code:xml}
<%@ taglib uri="/WEB-INF/tld/wwel.tld" prefix="x" %>

a[0] = ${x:vs('a[0]')}
a[0] * 4 = ${x:vs('a[0] * 4')}

Current action name: ${x:name()}
Top of ValueStack: ${x:top()}
{code}

To use this code you've got to add {{wwel.tld}} and {{Functions.java}} to your webapp project.

I would urge webworkers to define a set of functions that would be usable to wide community and include this in some future Webwork release.

{code:xml|title=wwel.tld}
<?xml version="1.0"?>
<taglib xmlns="http://java.sun.com/xml/ns/j2ee"
	xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
	xsi:schemaLocation="http://java.sun.com/xml/ns/j2ee http://java.sun.com/xml/ns/j2ee/web-jsptaglibrary_2_0.xsd"
	version="2.0">

<description>
This taglib enables access to WebWork2the ValueStack 
from JSP 2.0 Expression Language
</description>

<tlib-version>1.0</tlib-version>

<short-name>wwel</short-name>

<function>
	<name>vs</name>
	<function-class>com.nmote.wwel.Functions</function-class>
	<function-signature>
		java.lang.Object findOnValueStack(java.lang.String)
	</function-signature>
</function>

<function>
	<name>name</name>
	<function-class>com.nmote.wwel.Functions</function-class>
	<function-signature>
		java.lang.Object getActionName()
	</function-signature>
</function>

<function>
	<name>top</name>
	<function-class>com.nmote.wwel.Functions</function-class>
	<function-signature>
		java.lang.Object getTopOfValueStack()
	</function-signature>
</function>

</taglib>
{code}

{code:java|title=Functions.java}
package com.nmote.wwel;

import com.opensymphony.xwork.ActionContext;

/**
 * Utility functions for accessing webwork value stack and action context 
 * from JSP 2.0 EL taglibs.
 * 
 * @author Vjekoslav Nesek (vnesek@nmote.com)
 */
public class Functions {

	public static Object findOnValueStack(String expr) {
		ActionContext a = ActionContext.getContext();
		Object value = a.getValueStack().findValue(expr);
		return value;
	}
	
	public static Object getTopOfValueStack() {
		ActionContext a = ActionContext.getContext();
		Object value = a.getValueStack().peek();
		return value;
	}

	public static Object getActionName() {
		ActionContext a = ActionContext.getContext();
		Object value = a.getName();
		return value;
	}	
}
{code}