class ImmutableHeadersPlaceholder implements HeadersPlaceholder {

    @Override
    public Optional<String> resolve(final Map<String, String> headers, final String headerKey) {
        ConditionChecker.argumentNotEmpty(headerKey, "headerKey");
        ConditionChecker.argumentNotNull(headers, "headers");
        return Optional.ofNullable(headers.get(headerKey));
    }

    private  ImmutableHeadersPlaceholder();

}