code: private boolean isRunOnce(final ServletRequest pRequest) {
          // If request already filtered, return true (skip)
          if (pRequest.getAttribute(attribRunOnce) == ATTRIB_RUN_ONCE_VALUE) {
              return true;
          }
  
          // Set attribute and return false (continue)
          pRequest.setAttribute(attribRunOnce, ATTRIB_RUN_ONCE_VALUE);
  
          return false;
      }
docs: If request is filtered, returns true, otherwise marks request as filtered
  and returns false.
  A return value of false, indicates that the filter has not yet run.
  A return value of true, indicates that the filter has run for this
  request, and processing should not continue.
  <P/>
  Note that the method will mark the request as filtered on first
  invocation.
  <p/>
  @see #ATTRIB_RUN_ONCE_EXT
  @see #ATTRIB_RUN_ONCE_VALUE
  
  @param pRequest the servlet request
  @return {@code true} if the request is already filtered, otherwise
  {@code false}.