code: @Override
      public boolean isWrapperFor(@SuppressWarnings("rawtypes") Class wrappedType) {
          if (!ServletRequest.class.isAssignableFrom(wrappedType)) {
              throw new IllegalArgumentException("Given class " +
                                                 wrappedType.getName() + " not a subinterface of " +
                                                 ServletRequest.class.getName());
          }
  
          final ServletRequest request = getHttpServletRequest();
          @SuppressWarnings("unchecked")
          final Class<? extends ServletRequest> wrappedServletType = wrappedType;
  
          if (wrappedServletType.isAssignableFrom(request.getClass())) {
              return true;
          } else if (request instanceof ServletRequestWrapper) {
              return ((ServletRequestWrapper) request).isWrapperFor(wrappedType);
          } else {
              return false;
          }
      }
docs: /*
  (non-Javadoc)
  
  @see javax.servlet.ServletRequestWrapper#isWrapperFor(java.lang.Class)