Background:
ValidateProduct is a method in my VF page extension that uses the productsToVerify property (with getters/setters) to return a boolean. Using <apex:param I'm trying to set the productsToVerify property each time the <apex:repeat  iterates  through a record, then execute ValidateProduct which returns boolean - thus deciding whether to render  <apex:outputLink

Problem:  <apex:param isn't setting the productsToVerify property...it just remains null.   Thanks in advance for your help!

VF Code:
<apex:pageBlockTable value="{!JNLCampaigns}" var="junc">
   <apex:column>
      <apex:facet name="header">View X</apex:facet>
      <apex:repeat value="{!junc.CampaignMarketingMaterials__r}" var="campMark">
         <apex:outputLink rendered="false">
            <apex:param name="prodsParam" value="{!campMark.MarketingMaterial__r.Product_Name__c}" assignTo="{!productsToVerify}"/>
         </apex:outputLink>
         <apex:outputLink rendered="{!ValidateProduct}" value="{!campMark.MarketingMaterial__r.Form_Number__c}">VIEW PREVIEW</apex:outputLink><br />
      </apex:repeat>
   </apex:column>
</apex:pageBlockTable>​

Extension code for getValidateProduct method:
​public String productsToVerify{get;set{productsToVerify=value;}
public boolean getValidateProduct()
{  
system.debug(' productsToVerify ' + productsToVerify + ' ss ' + ss);
Boolean result = false;
if(!String.IsBlank(productsToVerify) && productsToVerify.contains(ss))
{
result = true;
system.debug(' result a ');
break;
}
else if(String.IsBlank(productsToVerify))
{
system.debug(' result b ');
result = true;
break;
}
return result;
}