@Override
    public String buildContext() {
        final String metaData = ((Collection<?>) getSource())
                .stream()
                .map(s -> ((MetaDataDO) s).getAppName())
                .collect(Collectors.joining(","));
        return String.format("the meta data [%s] is %s", metaData, StringUtils.lowerCase(getType().getType().toString()));
    }
@Test
    public void batchMetaDataDeletedContextTest() {
        BatchMetaDataDeletedEvent batchMetaDataChangedEvent =
                new BatchMetaDataDeletedEvent(Arrays.asList(one, two), "test-operator");

        String context = String.format("the meta data [%s] is %s",
                "testAppNameOne,testAppNameTwo", StringUtils.lowerCase(EventTypeEnum.META_DATA_DELETE.getType().toString()));

        assertEquals(context, batchMetaDataChangedEvent.buildContext());
    }