public abstract void filter(Metadata metadata) throws TikaException;
@Test
    public void testDateNormalizingFilter() throws Exception {
        //test that a Date lacking a timezone, if interpreted as Los Angeles, for example,
        //yields a UTC string that is properly +7 hours.
        Metadata m = new Metadata();
        m.set(TikaCoreProperties.CREATED, "2021-07-23T01:02:24");
        DateNormalizingMetadataFilter filter = new DateNormalizingMetadataFilter();
        filter.setDefaultTimeZone("America/Los_Angeles");
        filter.filter(m);
        assertEquals("2021-07-23T08:02:24Z", m.get(TikaCoreProperties.CREATED));
    }