@Override
    public DateTime touch(AccessToken accessToken) throws ValidationException {
        try {
            return lastAccessCache.get(accessToken.getId());
        } catch (ExecutionException e) {
            LOG.debug("Ignoring error: " + e.getMessage());
            return null;
        }
    }
@Test
    @MongoDBFixtures("accessTokensSingleToken.json")
    public void testTouch() throws Exception {
        accessTokenService.setLastAccessCache(1, TimeUnit.NANOSECONDS);
        final AccessToken token = accessTokenService.load("foobar");
        final DateTime firstAccess = accessTokenService.touch(token);

        Thread.sleep(1,0);
        final DateTime secondAccess = accessTokenService.touch(token);
        assertThat(secondAccess).isGreaterThan(firstAccess);
    }