code: protected boolean checkIfHeaders(final HttpServletRequest request, final HttpServletResponse response,
  			final Attributes resourceAttributes) throws IOException {
  
  		return checkIfMatch(request, response, resourceAttributes)
  				&& checkIfModifiedSince(request, response, resourceAttributes)
  				&& checkIfNoneMatch(request, response, resourceAttributes)
  				&& checkIfUnmodifiedSince(request, response, resourceAttributes);
  	}
docs: Check if the conditions specified in the optional If headers are
  satisfied.
  
  @param request
  The servlet request we are processing
  @param response
  The servlet response we are creating
  @param resourceAttributes
  The resource information
  @return boolean true if the resource meets all the specified conditions,
  and false if any of the conditions is not satisfied, in which
  case request processing is stopped