code: public void unsubscribeResourceFor(CmsDbContext dbc, String poolName, CmsPrincipal principal, CmsResource resource)
      throws CmsException {
  
          getSubscriptionDriver().unsubscribeResourceFor(dbc, poolName, principal, resource);
      }
docs: Unsubscribes the principal from the resource.<p>
  
  @param dbc the database context
  @param poolName the name of the database pool to use
  @param principal the principal that unsubscribes from the resource
  @param resource the resource to unsubscribe from
  
  @throws CmsException if something goes wrong