Using nameFilters for excluding a particular type of items

In eclipse's plugin extentions we can have pop up menus applicable for particular item depending on the type we specify in the nameFilter field. But now i want it to be reversed, means I want this pop up menu not to be shown for some types of items(based on its extensions).

So is it possible. Need help badly. T开发者_如何学Chanks

I haven't try it, but...

<viewerContribution
        id="IlexGuiConsole.viewerContribution2"
        targetID="IlexGuiConsole.viewerContribution2">
     <action
           class="ilexguiconsole.Action2"
           id="IlexGuiConsole.action2"
           label="label">
        <enablement>
           <not>
              <objectClass
                    name="ilexguiconsole.Object2">
              </objectClass>
           </not>
        </enablement>
     </action>
  </viewerContribution>