Question

My code here iterates the columns for each row and the rendered attribute is calculated every iteration, overcalling testRule.

<p:dataTable ...>
    <p:column ...>
        ...
    </p:column>

    <p:column rendered="#{managedBean.testRule('rules.canDoActions')}">
        <!-- Action buttons -->
        <h:commandButton ...>
        <h:commandButton ...>
    </p:column>
</p:dataTable>

To get better performance, I was wondering to set the result into a variable, but I don’t know how… It would become something like this:

   <?:??? var="canDoActions" value="#{managedBean.testRule('rules.canDoActions')}">
   <p:dataTable ...>
        <p:column ...>
            ...
        </p:column>

        <p:column rendered="#{canDoActions}">
            <!-- Action buttons -->
            <h:commandButton ...>
            <h:commandButton ...>
        </p:column>
    </p:dataTable>

Also, I’m not allowed to use Core Tag Library, wich means that <c:set ../> is out of question.

In that scope, how could I set a variable? Or, if not possible, what do you suggest to solve the performance?

Answer 1

I’m not allowed to use Core Tag Library, wich means that <c:set ../> is out of question

Then you can have it stored on Bean itself and check if it is null calculateRules and set value or simply return.

For Example:

HashMap<String, Boolean> map;

public boolean testRule(String stringInput) {
   Boolean result = map.get(stringInput);

   if (result == null) {
       //calculate and set in map
   }

   return result;
}