code: public void validate(String currentTestAction, Object contentToValidate) throws Exception {
          if (!isExpectationForAction(currentTestAction)) {
              return;
          }
          Log.info(thisClass, "validate", "Checking " + this);
          validate(contentToValidate);
      }
docs: Performs all of the steps necessary to verify that this particular expectation is met. If this expectation's test action is
  set to {@code null}, validation will proceed regardless of the test action passed to this method. Otherwise, if the current
  test action does not match the action for this expectation, validation is skipped.
  
  @param currentTestAction
  @param contentToValidate
  Some kind of object to validate against (typically some kind of HtmlUnit entity like a WebResponse)