On more than one occasion, a requirement has arisen that certain content needs to immediately be available on a Portal site without regard to WCM caching or Portlet caching. Generally, this means that the WCM Advanced Cache (a.k.a the "Processing" cache) needs to be emptied. Likewise, if a "hot fix" for a portlet whose HTML is cached (in the "WebSphere Base Cache"), the baseCache needs to be cleared. Sometime both need to be cleared if a WCM rendering portlet is also portlet cached.
I have written a portlet and included the source code that allows a users to select one or more caches to be cleared. The portlet notes the date and time that these selected caches were last cleared.
Here is the portlet along with the source code: ManageCachesPortlet
This portlet uses WebSphere APIs that require the user to have at least "Monitor" rights in the WAS console. To satisfy this requirement, I created a group, "WASMonitors". I created a page in the Portal upon which I've placed this portlet, gave the "Privileged User" role to this group for that page. Further, in the WAS console, under "Global security > Administrative group roles" I granted this group the role of "Monitor". All this insures that anyone using the ManageCaches portlet will have the appropriate rights to use the WebSphere MBeans utilized in the portlet.