Running APEX methods in Visualforce, is this possible?

Question

Maybe I'm just misunderstanding the capabilities of the Visualforce APIs and the use of functions in VisualForce but I'd like to do something like this:

Looking at the Rendered tag:

<apex:page ...>
    <apex:pageBlockSectionItem rendered="{!$Utils.checkChatterEnabled}">
        <apex:outputLabel for="enableChatterFeedTracking" value="Enable Chatter Feed Tracking" />
        <apex:outputText value="Chatter Enabled" />
    </apex:pageBlockSectionItem>
</apex:page>

And than I have a class with public or global visibility, that is NOT my controller or controller-extension:

global class Utils{
  global static Boolean checkChatterEnabled(){
    sObject feedEnabled = Database.query('SELECT Id FROM Meeting__Feed LIMIT 1');
    if(feedEnabled != null){
        return true;
    } else {
        return false;
    }
  }
}

Obviously this doesn't compile with a failure message:

Save error: Field $Utils.checkChatterEnabled does not exist

Is this possible? If so what am I doing wrong? If not, is their an "Idea" or "Success" article about it ...?

Thanks

Updated - to make checkChatterEnabled static.

Answer 1

To gain access to the functions for use in the rendered attribute (or anywhere else, for that matter), you would want to use an extension.

<apex:page standardController="Account" extensions="pageController,Util">
    <!-- code here -->
    <apex:pageBlockSectionItem rendered="{!Util.chatterFeedEnabled}">
        <!-- code -->
    </apex:pageBlockSectionItem>
</apex:page>

Your class can then be written to accept a StandardController:

public class Util {
    public Util(ApexPages.StandardController controller) { }
    public Boolean getChatterFeedEnabled() {
        ...
    }
}

You can then use this extension on multiple pages as you see fit. Note that Components are a different beast, however. If you use a component with a controller, there must also be a constructor accepting that controller as a parameter:

public Util(MyComponentController controller) { }

You can have as many constructors as you see fit (we have a multi-purpose class with eight constructors for various components).